This post was originally published on this site

Original release date: August 16, 2022

Summary

Actions for ZCS administrators to take today to mitigate malicious cyber activity:
• Patch all systems and prioritize patching known exploited vulnerabilities.
• Deploy detection signatures and hunt for indicators of compromise (IOCs).
• If ZCS was compromised, remediate malicious activity.

The Cybersecurity and Infrastructure Security Agency (CISA) and the Multi-State Information Sharing & Analysis Center (MS-ISAC) are publishing this joint Cybersecurity Advisory (CSA) in response to active exploitation of multiple Common Vulnerabilities and Exposures (CVEs) against Zimbra Collaboration Suite (ZCS), an enterprise cloud-hosted collaboration software and email platform. CVEs currently being exploited against ZCS include: 

• CVE-2022-24682 
• CVE-2022-27924 
• CVE-2022-27925 chained with CVE-2022-37042 
• CVE-2022-30333

Cyber threat actors may be targeting unpatched ZCS instances in both government and private sector networks. CISA and the MS-ISAC strongly urge users and administrators to apply the guidance in the Recommendations section of this CSA to help secure their organization’s systems against malicious cyber activity. CISA and the MS-ISAC encourage organizations who did not immediately update their ZCS instances upon patch release, or whose ZCS instances were exposed to the internet, to assume compromise and hunt for malicious activity using the third-party detection signatures in the Detection Methods section of this CSA. Organizations that detect potential compromise should apply the steps in the Incident Response section of this CSA.

Download the PDF version of this report: pdf, 355 kb

Technical Details

CVE-2022-27924

CVE-2022-27924 is a high-severity vulnerability enabling an unauthenticated malicious actor to inject arbitrary memcache commands into a targeted ZCS instance and cause an overwrite of arbitrary cached entries. The actor can then steal ZCS email account credentials in cleartext form without any user interaction. With valid email account credentials in an organization not enforcing multifactor authentication (MFA), a malicious actor can use spear phishing, social engineering, and business email compromise (BEC) attacks against the compromised organization. Additionally, malicious actors could use the valid account credentials to open webshells and maintain persistent access.

On March 11, 2022, researchers from SonarSource announced the discovery of this ZCS vulnerability. Zimbra issued fixes for releases 8.8.15 and 9.0 on May 10, 2022. In June 2022, SonarSource publicly released proof-of-concept (POC) exploits for this vulnerability.[1][2] Based on evidence of active exploitation, CISA added this vulnerability to the Known Exploited Vulnerabilities Catalog on August 4, 2022. Due to the POC and ease of exploitation, CISA and the MS-ISAC expect to see widespread exploitation of unpatched ZCS instances in government and private networks.

CVE-2022-27925 and CVE-2022-37042

CVE-2022-27925 is a high severity vulnerability in ZCS releases 8.8.15 and 9.0 that have mboximport functionality to receive a ZIP archive and extract files from it. An authenticated user has the ability to upload arbitrary files to the system thereby leading to directory traversal.[3] On August 10, 2022, researchers from Volexity reported widespread exploitation—against over 1,000 ZCS instances—of CVE-2022-27925 in conjunction with CVE-2022-37042.[4] CISA added both CVEs to the Known Exploited Vulnerabilities Catalog on August 11, 2022. 

CVE-2022-37042 is an authentication bypass vulnerability that affects ZCS releases 8.8.15 and 9.0. CVE-2022-37042 could allow an unauthenticated malicious actor access to a vulnerable ZCS instance. According to Zimbra, CVE-2022-37042 is found in the MailboxImportServlet function.[5][6] Zimbra issued fixes in late July 2022.

CVE-2022-30333

CVE-2022-30333 is a high-severity directory traversal vulnerability in RARLAB UnRAR on Linux and UNIX allowing a malicious actor to write to files during an extract (unpack) operation. A malicious actor can exploit CVE-2022-30333 against a ZCS server by sending an email with a malicious RAR file. Upon email receipt, the ZCS server would automatically extract the RAR file to check for spam or malware.[7] Any ZCS instance with unrar installed is vulnerable to CVE-2022-30333.

Researchers from SonarSource shared details about this vulnerability in June 2022.[8] Zimbra made configuration changes to use the 7zip program instead of unrar.[9] CISA added CVE-2022-3033 to the Known Exploited Vulnerabilities Catalog on August 9, 2022. Based on industry reporting, a malicious cyber actor is selling a cross-site scripting (XSS) exploit kit for the ZCS vulnerability to CVE 2022 30333. A Metasploit module is also available that creates a RAR file that can be emailed to a ZCS server to exploit CVE-2022-30333.[10]

CVE-2022-24682

CVE-2022-24682 is a medium-severity vulnerability that impacts ZCS webmail clients running releases before 8.8.15 patch 30 (update 1), which contain a cross-site scripting (XSS) vulnerability allowing malicious actors to steal session cookie files. Researchers from Volexity shared this vulnerability on February 3, 2022[11], and Zimbra issued a fix on February 4, 2022.[12] CISA added this vulnerability to the Known Exploited Vulnerabilities Catalog on February 25, 2022. 

DETECTION METHODS

Note: CISA and the MS-ISAC will update this section with additional IOCs and signatures as further information becomes available. 
CISA recommends administrators, especially at organizations that did not immediately update their ZCS instances upon patch release, to hunt for malicious activity using the following third-party detection signatures:

• Hunt for IOCs including:
  • 207.148.76[.]235 – a Cobalt Strike command and control (C2) domain
• Deploy third-party YARA rules to detect malicious activity:
  • See Volexity’s Mass Exploitation of (Un)authenticated Zimbra RCE: CVE-2022-27925

Mitigations

CISA and the MS-ISAC recommend organizations upgrade to the latest ZCS releases as noted on Zimbra Security – News & Alerts and Zimbra Security Advisories.

See Volexity’s Mass Exploitation of (Un)authenticated Zimbra RCE: CVE-2022-27925 for mitigation steps.

Additionally, CISA and the MS-ISAC recommend organizations apply the following best practices to reduce risk of compromise:

• Maintain and test an incident response plan.
• Ensure your organization has a vulnerability management program in place and that it prioritizes patch management and vulnerability scanning of known exploited vulnerabilities. Note: CISA’s Cyber Hygiene Services (CyHy) are free to all state, local, tribal, and territorial (SLTT) organizations, as well as public and private sector critical infrastructure organizations: cisa.gov/cyber-hygiene-services. 
• Properly configure and secure internet-facing network devices.
  • Do not expose management interfaces to the internet.
  • Disable unused or unnecessary network ports and protocols.
  • Disable/remove unused network services and devices.
• Adopt zero-trust principles and architecture, including:
  • Micro-segmenting networks and functions to limit or block lateral movements.
  • Enforcing phishing-resistant multifactor authentication (MFA) for all users and VPN connections.
  • Restricting access to trusted devices and users on the networks.

INCIDENT RESPONSE

If an organization’s system has been compromised by active or recently active threat actors in their environment, CISA and the MS-ISAC recommend the following initial steps:

1. Collect and review artifacts, such as running processes/services, unusual authentications, and recent network connections.
2. Quarantine or take offline potentially affected hosts.
3. Reimage compromised hosts.
4. Provision new account credentials.
5. Report the compromise to CISA via CISA’s 24/7 Operations Center (report@cisa.gov or 888-282-0870). SLTT government entities can also report to the MS-ISAC (SOC@cisecurity.org or 866-787-4722).

See the joint CSA from the cybersecurity authorities of Australia, Canada, New Zealand, the United Kingdom, and the United States on Technical Approaches to Uncovering and Remediating Malicious Activity for additional guidance on hunting or investigating a network, and for common mistakes in incident handling. CISA and the MS-ISAC also encourage government network administrators to see CISA’s Federal Government Cybersecurity Incident and Vulnerability Response Playbooks. Although tailored to federal civilian branch agencies, these playbooks provide operational procedures for planning and conducting cybersecurity incident and vulnerability response activities and detail steps for both incident and vulnerability response. 

ACKNOWLEDGEMENTS

CISA and the MS-ISAC would like to thank Volexity and Secureworks for their contributions to this advisory.

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. CISA and the MS-ISAC do not provide any warranties of any kind regarding this information. CISA and the MS-ISAC do not endorse any commercial product or service, including any subjects of analysis. Any reference to specific commercial products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring.

References

• [1] Hackers are actively exploiting password-stealing flaw in Zimbra
• [2] CISA adds Zimbra email vulnerability to its exploited vulnerabilities catalog
• [3] CVE-2022-27925 detail
• [4] Mass exploitation of (un)authenticated Zimbra RCE: CVE-2022-27925
• [5] CVE-2022-37042 detail
• [6] Authentication bypass in MailboxImportServlet vulnerability
• [7] CVE-2022-30333 detail
• [8] UnRAR vulnerability exploited in the wild, likely against Zimbra servers
• [9] Zimbra Collaboration Kepler 9.0.0 patch 25 GA release
• [10] Zimbra UnRAR path traversal
• [11] Operation EmailThief: Active exploitation of zero-day XSS vulnerability in Zimbra
• [12] Hotfix available 5 Feb for zero-day exploit vulnerability in Zimbra 8.8.15

Revisions

• August 16, 2022: Initial Version

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This post was originally published on this site

Original release date: August 11, 2022

Summary

Actions to take today to mitigate cyber threats from ransomware:

• Prioritize remediating known exploited vulnerabilities.
• Train users to recognize and report phishing attempts.
• Enable and enforce multifactor authentication.

Note: this joint Cybersecurity Advisory (CSA) is part of an ongoing #StopRansomware effort to publish advisories for network defenders that detail various ransomware variants and ransomware threat actors. These #StopRansomware advisories include recently and historically observed tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) to help organizations protect against ransomware. Visit stopransomware.gov to see all #StopRansomware advisories and to learn more about other ransomware threats and no-cost resources.

The Federal Bureau of Investigation (FBI) and the Cybersecurity and Infrastructure Security Agency (CISA) are releasing this joint CSA to disseminate known Zeppelin ransomware IOCs and TTPs associated with ransomware variants identified through FBI investigations as recently as 21 June 2022.

The FBI and CISA encourage organizations to implement the recommendations in the Mitigations section of this CSA to reduce the likelihood and impact of ransomware incidents.

Download the PDF version of this report: pdf, 999 kb

Download the YARA signature for Zeppelin: YARA Signature, .yar 125 kb

Technical Details

Note: this advisory uses the MITRE ATT&CK® for Enterprise framework, version 11. See MITRE ATT&CK for Enterprise for all referenced tactics and techniques.

Zeppelin ransomware is a derivative of the Delphi-based Vega malware family and functions as a Ransomware as a Service (RaaS). From 2019 through at least June 2022, actors have used this malware to target a wide range of businesses and critical infrastructure organizations, including defense contractors, educational institutions, manufacturers, technology companies, and especially organizations in the healthcare and medical industries. Zeppelin actors have been known to request ransom payments in Bitcoin, with initial amounts ranging from several thousand dollars to over a million dollars.

Zeppelin actors gain access to victim networks via RDP exploitation [T1133], exploiting SonicWall firewall vulnerabilities [T1190], and phishing campaigns [T1566]. Prior to deploying Zeppelin ransomware, actors spend one to two weeks mapping or enumerating the victim network to identify data enclaves, including cloud storage and network backups [TA0007]. Zeppelin actors can deploy Zeppelin ransomware as a .dll or .exe file or contained within a PowerShell loader. [1] 

Prior to encryption, Zeppelin actors exfiltrate [TA0010] sensitive company data files to sell or publish in the event the victim refuses to pay the ransom. Once the ransomware is executed, a randomized nine-digit hexadecimal number is appended to each encrypted file as a file extension, e.g., file.txt.txt.C59-E0C-929 [T1486]. A note file with a ransom note is left on compromised systems, frequently on the desktop (see figure 1 below).

 

 

The FBI has observed instances where Zeppelin actors executed their malware multiple times within a victim’s network, resulting in the creation of different IDs or file extensions, for each instance of an attack; this results in the victim needing several unique decryption keys.

 

Indicators of Compromise (IOC)

See table 1 below for IOCs as of June 2022 obtained from FBI incident response investigations.

MD5	SHA1	SHA256
981526650af8d6f8f20177a26abb513a	4fee2cb5c98abbe556e9c7ccfebe9df4f8cde53f	001938ed01bfde6b100927ff8199c65d1bff30381b80b846f2e3fe5a0d2df21d
c25d45e9bbfea29cb6d9ee0d9bf2864d	eaeff8d315cca71e997063a2baec5cc73fad9453	a42185d506e08160cb96c81801fbe173fb071f4a2f284830580541e057f4423b
183b6b0c90c1e0276a2015752344a4cf	1cb5e8132302b420af9b1e5f333c507d8b2a2441	aa7e2d63fc991990958dfb795a0aed254149f185f403231eaebe35147f4b5ebe
9349e1cc3de7c7f6893a21bd6c3c4a6b	db398e38ee6221df7e4aa49d8f96799cca4d87e1	a2a9385cbbcfacc2d541f5bd92c38b0376b15002901b2fd1cc62859e161a8037
c8f75487d0d496a3746e6c81a5ecc6dc	4b91a91a98a2f0128c80f8ceeef0f5d293adf0cd	54d567812eca7fc5f2ff566e7fb8a93618b6d2357ce71776238e0b94d55172b1
477eedb422041385e59a4fff72cb97c1	9892cc90e6712d3548e45f34f14f362bccedf0be	fb59f163a2372d09cd0fc75341d3972fdd3087d2d507961303656b1d791b17c6
5841ef35aaff08bb03d25e5afe3856a2	ffd228b0d7afe7cab4e9734f7093e7ba01c5a06e	1e3c5a0aa079f8dfcc49cdca82891ab78d016a919d9810120b79c5deb332f388
d6c4b253ab1d169cf312fec12cc9a28f	0f47c279fea1423c7a0e7bc967d9ff3fae7a0de8	347f14497df4df73bc414f4e852c5490b12db991a4b3811712bac7476a3f1bc9
fba7180ad49d6a7f3c60c890e2784704	f561f9e3c949fe87f12dbfa166ffb2eb85712419	7d8c4c742689c097ac861fcbf7734709fd7dcab1f7ef2ceffb4b0b7dec109f55
bc6c991941d9afbd522fa0a2a248a97a	a243ce234fc8294e2e2e526418b4eaadc2d6c84f	37c320983ae4c1fd0897736a53e5b0481edb1d1d91b366f047aa024b0fc0a86e
f3490951ae51922cb360a3d76a670159	e2cb60be111716e32db7ca2365ad6e73c30f0e21	894b03ed203cfa712a28ec472efec0ca9a55d6058115970fe7d1697a3ddb0072
e4f1f05c2e6c3fc2f3336a8c8799ffb4	dbd9fcf2b05e703d34181c46f4c22392b9fcc1da	307877881957a297e41d75c84e9a965f1cd07ac9d026314dcaff55c4da23d03e
aa2048271f0aef3383480ce4a7c93b52	512b16ea74027fa4d0055831de5e51278812c8de	bafd3434f3ba5bb9685e239762281d4c7504de7e0cfd9d6394e4a85b4882ff5d
f66b738e1bfe1f8aab510abed850c424	571f50fee0acad1da39fe06c75116461800cc719	faa79c796c27b11c4f007023e50509662eac4bca99a71b26a9122c260abfb3c6
bb30f050546f5d6e61fafc59eaf097c3	ee44179f64918f72a8d2e88a5074d89efab3d81b	e48cf17caffc40815efb907e522475722f059990afc19ac516592231a783e878
78621f1e196497d440afb57f4609fcf9	eed7c3bb3fc5181b88abeed2204997f350324022	4a4be110d587421ad50d2b1a38b108fa05f314631066a2e96a1c85cc05814080
f4e0ee0200de397691748a2cdcd7e34a	bd3f6b878284a63c72e8354e877e3f48d6fca53c	9ef90ec912543cc24e18e73299296f14cb2c931a5d633d4c097efa372ae59846
cf5a358a22326f09fd55983bb812b7d8	1addcffae4fd4211ea24202783c2ffad6771aa34	dd89d939c941a53d6188232288a3bd73ba9baf0b4ca6bf6ccca697d9ee42533f
7afe492a38ca6f27e24028aab68406b5	5870a3adbce9737319f3c9461586d5f2afbc7adb	79d6e498e7789aaccd8caa610e8c15836267c6a668c322111708cf80bc38286c
1da1c0115caca5ebf064380eb7490041	5edb8b651c7013ebaba2eb81c87df76a1e0724d6	b22b3625bcce7b010c0ee621434878c5f8d7691c2a101ae248dd221a70668ac0
8c3c663ffcf363d087f4e114a79945ca	905726d178962dd1d7fe87504d051aca440740b8	961fbc7641f04f9fed8391c387f01d64435dda6af1164be58c4cb808b08cc910
17c5cae3bce5832dd42986fe612517d9	6f70e73c53d7622d8c4808ae7849133df1343484	d618c1ccd24d29e911cd3e899a4df2625155297e80f4c5c1354bc2e79f70768c
bfe7f54f1f0640936dd7a3384608b1f6	9436ccee41c01ca3cb4db55c10884615aba76d19	8170612574f914eec9e66902767b834432a75b1d6ae510f77546af2a291a48a2
f28af04ef0370addfebfdd31f1ec25ed	cfcfa995c15d9f33de21d0dd88d3b95d0f91d6bc	5326f52bd9a7a52759fe2fde3407dc28e8c2caa33abf1c09c47b192a1c004c12
f3bcad5358f89df1eb0294ef53f54437	eb036759beb28f86ee981bdca4fad24152b82d8c	6bafc7e2c7edc2167db187f50106e57b49d4a0e1b9269f1d8a40f824f2ccb42b
b1f6370582fbaf5c51e826fecef53cd7	4b2d0127699f708a8116bff8f25c9d6140033197	f7af51f1b2b98b482885b702508bd65d310108a506e6d8cef3986e69f972c67d
de785ed922d4e737dc0fa0bb30a4de8b	4d280105e724db851f03de8fc76409ef4057ff2c	bc214c74bdf6f6781f0de994750ba3c50c0e10d9db3483183bd47f5cef154509
7a296f7c1ac4aeee18d4c23476735be7	c13542310f7a4e50a78247fc7334096ca09c5d7f	ed1548744db512a5502474116828f75737aec8bb11133d5e4ad44be16aa3666b
37f18b38e1af6533d93bbb3f2ddb86dc	d3929331d9bc278dea5607aec1574012a08de861	cf9b6dda84cbf2dbfc6edd7a740f50bddc128842565c590d8126e5d93c024ff2
291de974e5cbe5e3d47e3d17487e027f	def93f18aaf146fe8f3c4f9a257364f181197608	21807d9fcaa91a0945e80d92778760e7856268883d36139a1ad29ab91f9d983d
99d59c862a082b207a868e409ce2d97c	908a9026d61717b5fa29959478a9bd939da9206f	0d22d3d637930e7c26a0f16513ec438243a8a01ea9c9d856acbcda61fcb7b499
d27125d534e398f1873b7f4835a79f09	1862f063c30cd02cfea6070d3dba41ac5eee2a35	6fbfc8319ed7996761b613c18c8cb6b92a1eaed1555dae6c6b8e2594ac5fa2b9
4534f2afe5f7df1d998f37ad4e35afeb	e2cc94e471509f9fa58620b8bb56d77f2cfe74b0	e8596675fef4ad8378e4220c22f4358fdb4a20531b59d7df5382c421867520a9
7ab0676262c681b8ec15bdada17d7476	2f1803d444891abb604864d476a8feac0d614f77	353e59e96cbf6ea6c16d06da5579d3815aaaeeefacabd7b35ba31f7b17207c5b
d7d3d23a5e796be844af443bda5cd67e	a9771c591f6ccc2f3419d571c64ab93228785771	85f9bf4d07bc2ac1891e367f077dd513d6ca07705bffd1b648d32a7b2dc396f5
0a1cd4efda7543cec406a6822418daf6	af4f8d889d6a2049e7a379ea197f8cd361feb074	614cb70659ef5bb2f641f09785adc4ab5873e0564a5303252d3c141a899253b2
23eda650479fc4908d0ddff713508025	b1e6527c10f68586f7f1a279ed439d46c3f12a06	fb3e0f1e6f53ffe680d66d2143f06eb6363897d374dc5dc63eb2f28188b8ad83
6607d8c1a28d7538e2a6565cf40d1260	f618879c011cde344066072949f025827feea663	594df9c402abfdc3c838d871c3395ac047f256b2ac2fd6ff66b371252978348d
caa7a669da39ffd8a3a4f3419018b363	44538b7f8f065e3cef0049089a8522a76a7fccc6	2dffe3ba5c70af51ddf0ff5a322eba0746f3bf3ae0751beb3dc0059ed3faaf3d
48b844494a746ca96c7b96d6bd90f45f	7bf83b98f798f3a8f4ce85b6d29554a435e516e3	45fba1ef399f41227ae4d14228253237b5eb464f56cab92c91a6a964dc790622
9c13ab7b79aec8dc02869999773cd4b2	4b4d865132329e0dd1d129e85fc4fa9ad0c1d206	774ef04333c3fb2a6a4407654e28c2900c62bd202ad6e5909336eb9bc180d279
450e5bf4b42691924d09267ac1a570cb	665a563157f4aa0033a15c88f55ac4fa28397b49	677035259ba8342f1a624fd09168c42017bdca9ebc0b39bf6c37852899331460
51104215a618a5f56ad9c884d6832f79	801580a46f9759ceeeebbce419d879e2ed6943fe	26ec12b63c0e4e60d839aea592c4b5dcff853589b53626e1dbf8c656f4ee6c64
73627cbe2ba139e2ec26889a4e8d6284	1116dc35993fce8118e1e5421000a70b6777433f	37efe10b04090995e2f3d9f932c3653b27a65fc76811fa583934a725d41a6b08
935f54b6609c5339001579e96dc34244	a809327d39fab61bfcfac0c97b1d4b3bfb9a2cfe	a5847867730e7849117c31cdae8bb0a25004635d49f366fbfaebce034d865d7d
ba681db97f283c2e784d9bb4969b1f5a	5d28acf52f399793e82ec7e79da47d372d9175d7	e61edbddf9aed8a52e9be1165a0440f1b6e9943ae634148df0d0517a0cf2db13
c1ab7b68262b5ab31c45327e7138fd25	b8c74327831e460d2b2a8eb7e68ee68938779d8d	746f0c02c832b079aec221c04d2a4eb790287f6d10d39b95595a7df4086f457f
f818938b987236cdd41195796b4c1fb5	bfed40f050175935277c802cbbbce132f44c06ec	b191a004b6d8a706aba82a2d1052bcb7bed0c286a0a6e4e0c4723f073af52e7c
0a1cd4efda7543cec406a6822418daf6	af4f8d889d6a2049e7a379ea197f8cd361feb074	614cb70659ef5bb2f641f09785adc4ab5873e0564a5303252d3c141a899253b2
d7d3d23a5e796be844af443bda5cd67e	a9771c591f6ccc2f3419d571c64ab93228785771	85f9bf4d07bc2ac1891e367f077dd513d6ca07705bffd1b648d32a7b2dc396f5
7ab0676262c681b8ec15bdada17d7476	2f1803d444891abb604864d476a8feac0d614f77	353e59e96cbf6ea6c16d06da5579d3815aaaeeefacabd7b35ba31f7b17207c5b
4534f2afe5f7df1d998f37ad4e35afeb	e2cc94e471509f9fa58620b8bb56d77f2cfe74b0	e8596675fef4ad8378e4220c22f4358fdb4a20531b59d7df5382c421867520a9
d27125d534e398f1873b7f4835a79f09	1862f063c30cd02cfea6070d3dba41ac5eee2a35	6fbfc8319ed7996761b613c18c8cb6b92a1eaed1555dae6c6b8e2594ac5fa2b9
99d59c862a082b207a868e409ce2d97c	908a9026d61717b5fa29959478a9bd939da9206f	0d22d3d637930e7c26a0f16513ec438243a8a01ea9c9d856acbcda61fcb7b499

 

MITRE ATT&CK TECHNIQUES

 Zeppelin actors use the ATT&CK techniques listed in Table 2.

Table 2: Zeppelin Actors Att&ck Techniques for Enterprise

Initial Access
Technique Title	ID	Use
Exploit External Remote Services	T1133	Zeppelin actors exploit RDP to gain access to victim networks.
Exploit Public-Facing Application	T1190	Zeppelin actors exploit vulnerabilities in internet-facing systems to gain access to systems
Phishing	T1566	Zeppelin actors have used phishing and spear phishing to gain access to victims’ networks.
Execution
Technique Title	ID	Use
Malicious Link	T1204.001	Zeppelin actors trick users to click a malicious link to execute malicious macros.
Malicious File Attachment	T1204.002	Zeppelin actors trick users to click a malicious attachment disguised as advertisements to execute malicious macros.
Persistence
Technique Title	ID	Use
Modify System Process	T1543.003	Zeppelin actors encrypt Windows Operating functions to preserve compromised system functions.
Impact
Technique Title	ID	Use
Data Encrypted for Impact	T1486	Zeppelin actors have encrypted data on target systems or on large numbers of systems in a network to interrupt availability to system and network resources.

 

DETECTION

Download the YARA signature for Zeppelin: YARA Signature, .yar 125 kb

Mitigations

The FBI and CISA recommend network defenders apply the following mitigations to limit potential adversarial use of common system and network discovery techniques and to reduce the risk of compromise by Zeppelin ransomware:

• Implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers in a physically separate, segmented, and secure location (i.e., hard drive, storage device, the cloud).
• Require all accounts with password logins (e.g., service account, admin accounts, and domain admin accounts) to comply with National Institute for Standards and Technology (NIST) standards for developing and managing password policies.
  • Use longer passwords consisting of at least 8 characters and no more than 64 characters in length;
  • Store passwords in hashed format using industry-recognized password managers;
  • Add password user “salts” to shared login credentials;
  • Avoid reusing passwords;
  • Implement multiple failed login attempt account lockouts;
  • Disable password “hints”;
  • Refrain from requiring password changes more frequently than once per year. Note: NIST guidance suggests favoring longer passwords instead of requiring regular and frequent password resets. Frequent password resets are more likely to result in users developing password “patterns” cyber criminals can easily decipher.
  • Require administrator credentials to install software.

• Require multifactor authentication for all services to the extent possible, particularly for webmail, virtual private networks, and accounts that access critical systems. 
• Keep all operating systems, software, and firmware up to date. Timely patching is one of the most efficient and cost-effective steps an organization can take to minimize its exposure to cybersecurity threats. Prioritize patching SonicWall firewall vulnerabilities and known exploited vulnerabilities in internet-facing systems. Note: SonicWall maintains a vulnerability list that includes Advisory ID, CVE, and mitigation. Their list can be found at psirt.global.sonicwall.com/vuln-list. 
• Segment networks to prevent the spread of ransomware. Network segmentation can help prevent the spread of ransomware by controlling traffic flows between—and access to—various subnetworks and by restricting adversary lateral movement. 
• Identify, detect, and investigate abnormal activity and potential traversal of the indicated ransomware with a networking monitoring tool. To aid in detecting the ransomware, implement a tool that logs and reports all network traffic, including lateral movement activity on a network. Endpoint detection and response (EDR) tools are particularly useful for detecting lateral connections as they have insight into common and uncommon network connections for each host. 
• Install, regularly update, and enable real time detection for antivirus software on all hosts.
• Review domain controllers, servers, workstations, and active directories for new and/or unrecognized accounts.
• Audit user accounts with administrative privileges and configure access controls according to the principle of least privilege. 
• Disable unused ports.
• Consider adding an email banner to emails received from outside your organization.
• Disable hyperlinks in received emails.
• Implement time-based access for accounts set at the admin level and higher. For example, the Just-in-Time (JIT) access method provisions privileged access when needed and can support enforcement of the principle of least privilege (as well as the Zero Trust model). This is a process where a network-wide policy is set in place to automatically disable admin accounts at the Active Directory level when the account is not in direct need. Individual users may submit their requests through an automated process that grants them access to a specified system for a set timeframe when they need to support the completion of a certain task. 
• Disable command-line and scripting activities and permissions. Privilege escalation and lateral movement often depend on software utilities running from the command line. If threat actors are not able to run these tools, they will have difficulty escalating privileges and/or moving laterally. 
• Maintain offline backups of data, and regularly maintain backup and restoration.  By instituting this practice, the organization ensures they will not be severely interrupted, and/or only have irretrievable data. 
• Ensure all backup data is encrypted, immutable (i.e., cannot be altered or deleted), and covers the entire organization’s data infrastructure.

RESOURCES

• Stopransomware.gov is a whole-of-government approach that gives one central location for ransomware resources and alerts.
• Resource to mitigate a ransomware attack: CISA-Multi-State Information Sharing and Analysis Center (MS-ISAC) Joint Ransomware Guide.
• No-cost cyber hygiene services: Cyber Hygiene Services and Ransomware Readiness Assessment.

REPORTING

The FBI is seeking any information that can be shared, to include boundary logs showing communication to and from foreign IP addresses, a sample ransom note, communications with Zeppelin actors, Bitcoin wallet information, decryptor files, and/or a benign sample of an encrypted file. The FBI and CISA do not encourage paying ransom as payment does not guarantee victim files will be recovered. Furthermore, payment may also embolden adversaries to target additional organizations, encourage other criminal actors to engage in the distribution of ransomware, and/or fund illicit activities. Regardless of whether you or your organization have decided to pay the ransom, the FBI and CISA urge you to promptly report ransomware incidents to a local FBI Field Office, CISA at us-cert.cisa.gov/report, or the U.S. Secret Service (USSS) at a USSS Field Office.

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. CISA and the FBI do not endorse any commercial product or service, including any subjects of analysis. Any reference to specific commercial products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by CISA or the FBI.

References

• [1] What is Zeppelin Ransomware? Steps to Prepare, Respond, and Prevent Infection (coresecurity.com)

Revisions

• August 11, 2022: Initial Version

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This post was originally published on this site

Original release date: August 4, 2022

Summary

Immediate Actions You Can Take Now to Protect Against Malware:

• Patch all systems and prioritize patching known exploited vulnerabilities.
• Enforce multifactor authentication (MFA).
• Secure Remote Desktop Protocol (RDP) and other risky services.
• Make offline backups of your data.
• Provide end-user awareness and training about social engineering and phishing.

This joint Cybersecurity Advisory (CSA) was coauthored by the Cybersecurity and Infrastructure Security Agency (CISA) and the Australian Cyber Security Centre (ACSC). This advisory provides details on the top malware strains observed in 2021. Malware, short for “malicious software,” can compromise a system by performing an unauthorized function or process. Malicious cyber actors often use malware to covertly compromise and then gain access to a computer or mobile device. Some examples of malware include viruses, worms, Trojans, ransomware, spyware, and rootkits.[1]

In 2021, the top malware strains included remote access Trojans (RATs), banking Trojans, information stealers, and ransomware. Most of the top malware strains have been in use for more than five years with their respective code bases evolving into multiple variations. The most prolific malware users are cyber criminals, who use malware to deliver ransomware or facilitate theft of personal and financial information.

CISA and ACSC encourage organizations to apply the recommendations in the Mitigations sections of this joint CSA. These mitigations include applying timely patches to systems, implementing user training, securing Remote Desktop Protocol (RDP), patching all systems especially for known exploited vulnerabilities, making offline backups of data, and enforcing multifactor authentication (MFA).

Download the PDF version of this report: pdf, 489 kb

Technical Details

Key Findings

The top malware strains of 2021 are: Agent Tesla, AZORult, Formbook, Ursnif, LokiBot, MOUSEISLAND, NanoCore, Qakbot, Remcos, TrickBot and GootLoader.

• Malicious cyber actors have used Agent Tesla, AZORult, Formbook, LokiBot, NanoCore, Remcos, and TrickBot for at least five years.
• Malicious cyber actors have used Qakbot and Ursnif for more than a decade.

Updates made by malware developers, and reuse of code from these malware strains, contribute to the malware’s longevity and evolution into multiple variations. Malicious actors’ use of known malware strains offers organizations opportunities to better prepare, identify, and mitigate attacks from these known malware strains.
The most prolific malware users of the top malware strains are cyber criminals, who use malware to deliver ransomware or facilitate theft of personal and financial information.

• Qakbot and TrickBot are used to form botnets and are developed and operated by Eurasian cyber criminals known for using or brokering botnet-enabled access to facilitate highly lucrative ransomware attacks. Eurasian cyber criminals enjoy permissive operating environments in Russia and other former Soviet republics.
• According to U.S. government reporting, TrickBot malware often enables initial access for Conti ransomware, which was used in nearly 450 global ransomware attacks in the first half of 2021. As of 2020, malicious cyber actors have purchased access to systems compromised by TrickBot malware on multiple occasions to conduct cybercrime operations.
• In 2021, cyber criminals conducted mass phishing campaigns with Formbook, Agent Tesla, and Remcos malware that incorporated COVID-19 pandemic themes to steal personal data and credentials from businesses and individuals.

In the criminal malware industry, including malware as a service (MaaS), developers create malware that malware distributors often broker to malware end-users.[2] Developers of these top 2021 malware strains continue to support, improve, and distribute their malware over several years. Malware developers benefit from lucrative cyber operations with low risk of negative consequences. Many malware developers often operate from locations with few legal prohibitions against malware development and deployment. Some developers even market their malware products as legitimate cyber security tools. For example, the developers of Remcos and Agent Tesla have marketed the software as legitimate tools for remote management and penetration testing. Malicious cyber actors can purchase Remcos and Agent Tesla online for low cost and have been observed using both tools for malicious purposes.

Top Malware

Agent Tesla

• Overview: Agent Tesla is capable of stealing data from mail clients, web browsers, and File Transfer Protocol (FTP) servers. This malware can also capture screenshots, videos, and Windows clipboard data. Agent Tesla is available online for purchase under the guise of being a legitimate tool for managing your personal computer. Its developers continue to add new functionality, including obfuscation capabilities and targeting additional applications for credential stealing.[3][4]
• Active Since: 2014
• Malware Type: RAT
• Delivery Method: Often delivered as a malicious attachment in phishing emails.
• Resources: See the MITRE ATT&CK page on Agent Tesla.

AZORult

• Overview: AZORult is used to steal information from compromised systems. It has been sold on underground hacker forums for stealing browser data, user credentials, and cryptocurrency information. AZORult’s developers are constantly updating its capabilities.[5][6]
• Active Since: 2016
• Malware Type: Trojan
• Delivery Method: Phishing, infected websites, exploit kits (automated toolkits exploiting known software vulnerabilities), or via dropper malware that downloads and installs AZORult.
• Resources: See the MITRE ATT&CK page on AZORult and the Department of Health and Human Services (HHS)’s AZORult brief.

FormBook

• Overview: FormBook is an information stealer advertised in hacking forums. ForrmBook is capable of key logging and capturing browser or email client passwords, but its developers continue to update the malware to exploit the latest Common Vulnerabilities and Exposures (CVS)[7], such as CVE-2021-40444 Microsoft MSHTML Remote Code Execution Vulnerability.[8][9]
• Active Since: At least 2016
• Malware Type: Trojan
• Delivery Method: Usually delivered as an attachment in phishing emails.
• Resources: See Department of Health and Human Services (HHS)’s Sector Note on Formbook Malware Phishing Campaigns.

Ursnif

• Overview: Ursnif is a banking Trojan that steals financial information. Also known as Gozi, Ursnif has evolved over the years to include a persistence mechanism, methods to avoid sandboxes and virtual machines, and search capability for disk encryption software to attempt key extraction for unencrypting files.[10][11][12] Based on information from trusted third parties, Ursnif infrastructure is still active as of July 2022.
• Active Since: 2007
• Malware Type: Trojan
• Delivery Method: Usually delivered as a malicious attachment to phishing emails.
• Resources: See the MITRE ATT&CK page on Ursnif.

LokiBot

• Overview: LokiBot is a Trojan malware for stealing sensitive information, including user credentials, cryptocurrency wallets, and other credentials. A 2020 LokiBot variant was disguised as a launcher for the Fortnite multiplayer video game.[13][14]
• Active Since: 2015
• Malware Type: Trojan
• Delivery Method: Usually delivered as a malicious email attachment.
• Resources: See CISA’s LokiBot Malware alert and the MITRE ATT&CK page on LokiBot.

MOUSEISLAND

• Overview: MOUSEISLAND is usually found within the embedded macros of a Microsoft Word document and can download other payloads. MOUSEISLAND may be the initial phase of a ransomware attack.[15]
• Active Since: At least 2019
• Malware Type: Macro downloader
• Delivery Method: Usually distributed as an email attachment.
• Resources: See Mandiant’s blog discussing MOUSEISLAND.

NanoCore

• Overview: NanoCore is used for stealing victims’ information, including passwords and emails. NanoCore could also allow malicious users to activate computers’ webcams to spy on victims. Malware developers continue to develop additional capabilities as plug-ins available for purchase or as a malware kit or shared amongst malicious cyber actors.[16][17][18]
• Active Since: 2013
• Malware Type: RAT
• Delivery Method: Has been delivered in an email as an ISO disk image within malicious ZIP files; also found in malicious PDF documents hosted on cloud storage services.
• Resources: See the MITRE ATT&CK page on NanoCore and the HHS Sector Note: Remote Access Trojan Nanocore Poses Risk to HPH Sector.

Qakbot

• Overview: originally observed as a banking Trojan, Qakbot has evolved in its capabilities to include performing reconnaissance, moving laterally, gathering and exfiltrating data, and delivering payloads. Also known as QBot or Pinksliplot, Qakbot is modular in nature enabling malicious cyber actors to configure it to their needs. Qakbot can also be used to form botnets.[19][20]
• Active Since: 2007
• Malware Type: Trojan
• Delivery Method: May be delivered via email as malicious attachments, hyperlinks, or embedded images.
• Resources: See the MITRE ATT&CK page on Qakbot and the Department of Health and Human Services (HHS) Qbot/Qakbot Malware brief.

Remcos

• Overview: Remcos is marketed as a legitimate software tool for remote management and penetration testing. Remcos, short for Remote Control and Surveillance, was leveraged by malicious cyber actors conducting mass phishing campaigns during the COVID-19 pandemic to steal personal data and credentials. Remcos installs a backdoor onto a target system. Malicious cyber actors then use the Remcos backdoor to issue commands and gain administrator privileges while bypassing antivirus products, maintaining persistence, and running as legitimate processes by injecting itself into Windows processes.[21][22]
• Active Since: 2016
• Malware Type: RAT
• Delivery Method: Usually delivered in phishing emails as a malicious attachment.
• Resources: See the MITRE ATT&CK page on Remcos.

TrickBot

• Overview: TrickBot malware is often used to form botnets or enabling initial access for the Conti ransomware or Ryuk banking trojan. TrickBot is developed and operated by a sophisticated group of malicious cyber actors and has evolved into a highly modular, multi-stage malware. In 2020, cyber criminals used TrickBot to target the Healthcare and Public Health (HPH) Sector and then launch ransomware attacks, exfiltrate data, or disrupt healthcare services. Based on information from trusted third parties, TrickBot’s infrastructure is still active in July 2022.[23][24][25][26]
• Active Since: 2016
• Malware Type: Trojan
• Delivery Method: Usually delivered via email as a hyperlink.
• Resources: See the MITRE ATT&CK page on Trickbot and the Joint CSA on TrickBot Malware.

GootLoader

• Overview: GootLoader is a malware loader historically associated with the GootKit malware. As its developers updated its capabilities, GootLoader has evolved from a loader downloading a malicious payload into a multi-payload malware platform. As a loader malware, GootLoader is usually the first-stage of a system compromise. By leveraging search engine poisoning, GootLoader’s developers may compromise or create websites that rank highly in search engine results, such as Google search results.[27]
• Active Since: At least 2020
• Malware Type: Loader
• Delivery Method: Malicious files available for download on compromised websites that rank high as search engine results
• Resources: See New Jersey’s Cybersecurity & Communications Integration Cell (NJCCIC) page on GootLooader and BlackBerry’s Blog on GootLoader.

Mitigations

Below are the steps that CISA and ACSC recommend organizations take to improve their cybersecurity posture based on known adversary tactics, techniques, and procedures (TTPs). CISA and ACSC urge critical infrastructure organizations to prepare for and mitigate potential cyber threats immediately by (1) updating software, (2) enforcing MFA, (3) securing and monitoring RDP and other potentially risky services, (4) making offline backups of your data, and (5) providing end-user awareness and training.

• Update software, including operating systems, applications, and firmware, on IT network assets. Prioritize patching known exploited vulnerabilities and critical and high vulnerabilities that allow for remote code execution or denial-of-service on internet-facing equipment.
  • Consider using a centralized patch management system.
  • Consider signing up for CISA’s cyber hygiene services, including vulnerability scanning, to help reduce exposure to threats. CISA’s vulnerability scanning service evaluates external network presence by executing continuous scans of public, static IP addresses for accessible services and vulnerabilities.

• Enforce MFA to the greatest extent possible and require accounts with password logins, including service accounts, to have strong passwords. Do not allow passwords to be used across multiple accounts or stored on a system to which an adversary may have access. Additionally, ACSC has issued guidance on implementing multifactor authentication for hardening authentication systems.
• If you use RDP and/or other potentially risky services, secure and monitor them closely. RDP exploitation is one of the top initial infection vectors for ransomware, and risky services, including RDP, can allow unauthorized access to your session using an on-path attacker.
  • Limit access to resources over internal networks, especially by restricting RDP and using virtual desktop infrastructure. After assessing risks, if RDP is deemed operationally necessary, restrict the originating sources, and require MFA to mitigate credential theft and reuse. If RDP must be available externally, use a virtual private network (VPN) or other means to authenticate and secure the connection before allowing RDP to connect to internal devices. Monitor remote access/RDP logs, enforce account lockouts after a specified number of attempts to block brute force attempts, log RDP login attempts, and disable unused remote access/RDP ports.
  • Ensure devices are properly configured and that security features are enabled. Disable ports and protocols that are not being used for a business purpose (e.g., RDP Transmission Control Protocol Port 3389). 

• Maintain offline (i.e., physically disconnected) backups of data. Backup procedures should be conducted on a frequent, regular basis (at a minimum every 90 days). Regularly test backup procedures and ensure that backups are isolated from network connections that could enable the spread of malware.
  • Ensure the backup keys are kept offline as well, to prevent them being encrypted in a ransomware incident.
  • Ensure all backup data is encrypted, immutable (i.e., cannot be altered or deleted), and covers the entire organization’s data infrastructure with a particular focus on key data assets.

• Provide end-user awareness and training to help prevent successful targeted social engineering and spearphishing campaigns. Phishing is one of the top infection vectors for ransomware.
  • Ensure that employees are aware of potential cyber threats and delivery methods.
  • Ensure that employees are aware of what to do and whom to contact when they receive a suspected phishing email or suspect a cyber incident.

As part of a longer-term effort, implement network segmentation to separate network segments based on role and functionality. Network segmentation can help prevent the spread of ransomware and threat actor lateral movement by controlling traffic flows between—and access to—various subnetworks. The ACSC has observed ransomware and data theft incidents in which Australian divisions of multinational companies were impacted by ransomware incidents affecting assets maintained and hosted by offshore divisions outside their control.

RESOURCES

• For alerts on malicious and criminal cyber activity, see the FBI Internet Crime Complaint Center webpage.
• For more information and resources on protecting against and responding to ransomware, refer to StopRansomware.gov, a centralized, U.S. Government webpage providing ransomware resources and alerts.
• The ACSC recommends organizations implement eight essential mitigation strategies from the ACSC’s Strategies to Mitigate Cyber Security Incidents as a cybersecurity baseline. These strategies, known as the “Essential Eight,” make it much harder for adversaries to compromise systems.
• Refer to the ACSC’s practical guides on how to protect yourself against ransomware attacks and what to do if you are held at ransom at cyber.gov.au.

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. CISA and ACSC do not endorse any commercial product or service, including any subjects of analysis. Any reference to specific commercial products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring.

APPENDIX: SNORT SIGNATURES FOR THE TOP 2021 MALWARE

Malware	Snort Detection Signature
Agent Tesla	alert any any -> any any (msg:”HTTP GET request /aw/aw.exe”; flow:established,to_server; sid:1; rev:1; content:”GET”; http_method; content:”/aw/aw.exe”; http_uri; reference:url, https://www.datto.com/blog/what-is-agent-tesla-spyware-and-how-does-it-work; metadata:service http;)
AZORult	alert tcp any any -> any any (msg:”HTTP Server Content Data contains ‘llehS|2e|tpircSW'”; sid:1; rev:1; flow:established,from_server; file_data; content:”llehS|2e|tpircSW”; nocase; fast_pattern:only; pcre:”/GCM(?:x20|%20)*W-O*/i”; reference:url,maxkersten.nl/binary-analysis-course/malware-analysis/azorult-loader-stages/; metadata:service http;)
AZORult	alert tcp any any -> any any (msg:”HTTP POST Client Body contains ‘J/|fb|’ and ‘/|fb|'”; sid:1; rev:1; flow:established,to_server; content:”POST”; http_method; content:”.php”; http_uri; content:”J/|fb|”; http_client_body; fast_pattern; content:”/|fb|”; http_client_body; depth:11; content:!”Referer|3a 20|”; http_header; metadata:service http;)
FormBook	alert tcp any any -> any any (msg:”HTTP URI POST contains ‘&sql=1’ at the end”; sid:1; rev:1; flow:established,to_server; content:”&sql=1″; http_uri; fast_pattern:only; content:”POST”; http_method; pcre:”/(?(DEFINE)(?’b64std'[a-zA-Z0-9+/=]+?))(?(DEFINE)(?’b64url'[a-zA-Z0-9_-]+?))^/[a-z0-9]{3,4}/?(?P>b64url){3,8}=(?P>b64std){40,90}&(?P>b64url){2,6}=(?P>b64url){4,11}&sql=1$/iU”; reference:url,www.malware-traffic-analysis.net/2018/02/16/index.html; metadata:service http;)
	alert tcp any any -> any any (msg:”HTTP URI GET/POST contains ‘/list/hx28/config.php?id='”; sid:1; rev:1; flow:established,to_server; content:”/list/hx28/config.php?id=”; http_uri; fast_pattern:only; content:”Connection|3a 20|close|0d 0a|”; http_header; reference:url,www.fireeye.com/blog/threat-research/2017/10/formbook-malware-distribution-campaigns.html; metadata:service http;)
Ursnif	alert tcp any any -> any any (msg:”HTTP POST Data contains .bin filename, long URI contains ‘/images/'”; sid:1; rev:1; flow:established,to_server;  urilen:>60,norm; content:”/images/”; http_uri; depth:8; content:”POST”; nocase; http_method; content:”Content-Disposition|3a 20|form-data|3b 20|name=|22|upload_file|22 3b 20|filename=|22|”; http_client_body; content:”|2e|bin|22 0d 0a|”; http_client_body; distance:1; within:32; fast_pattern;  reference:url,www.broadanalysis.com/2016/03/23/angler-ek-sends-data-stealing-payload/; metadata:service http;)
	alert tcp any any -> any any (msg:”HTTP URI GET/POST contains ‘/images/’ plus random sub directories and an Image File (Ursnif)”; sid:1; rev:1; flow:established,to_server;  content:”/images/”; http_uri; fast_pattern:only; content:!”Host: www.urlquery.net”; http_header; pcre:”//images(/(?=[a-z0-9_]{0,22}[A-Z][a-z0-9_]{0,22}[A-Z])(?=[A-Z0-9_]{0,22}[a-z])[A-Za-z0-9_]{1,24}){5,20}/[a-zA-Z0-9_]+.(?:gif|jpeg|jpg|bmp)$/U”; metadata:service http)
LokiBot	alert tcp any any -> any any (msg:”HTTP Client Header contains ‘User-Agent|3a 20|Mozilla/4.08 (Charon|3b| Inferno)'”; sid:1; rev:1; flow:established,to_server; content:”User-Agent|3a 20|Mozilla/4.08 (Charon|3b| Inferno)|0d 0a|”; http_header; fast_pattern:only; metadata:service http; )
LokiBot	alert tcp any any -> any any (msg:”HTTP URI POST contains ‘/*/fre.php’ post-infection”; sid:1; rev:1; flow:established,to_server; content:”/fre.php”; http_uri; fast_pattern:only; urilen:<50,norm; content:”POST”; nocase; http_method; pcre:”//(?:alien|lokyd|donep|jemp|lokey|new2|loki|Charles|sev7n|dbwork|scroll/NW|wrk|job|fived?|donemy|animationdkc|love|Masky|vd|lifetn|Ben)/fre.php$/iU”; metadata:service http;)
LokiBot	alert tcp any any -> any any (msg:”HTTP URI POST contains ‘/w.php/'”; sid:1; rev:1; flow:established,to_server; content:”/w.php/”; http_uri; fast_pattern:only; content:”POST”; nocase; http_method; pcre:”//w+/w.php/[a-z]{13}$/iU”;  metadata:service http;)
MOUSEISLAND	alert tcp any any -> any any (msg:”HTTP URI GET contains ‘/assets/<8-80 hex>/<4-16 alnum>?<3-6 alnum>='”; sid:9206287; rev:1; flow:established,to_server; content:”/assets/”; http_uri; fast_pattern:only; content:”HTTP/1.1|0d 0a|”; depth:256; content:!”|0d 0a|Cookie:”; content:!”|0d 0a|Referer:”; pcre:”//assets/[a-fA-F0-9/]{8,80}/[a-zA-Z0-9]{4,16}?[a-z0-9]{3,6}=/U”;  metadata:service http;)
NanoCore	alert tcp any any -> any 25 (msg:”SMTP Attachment Filename ‘Packinglist-Invoice101.pps'”; sid:1; rev:1; flow:established,to_server,only_stream; content:”Content-Disposition|3a 20|attachment|3b|”; content:”Packinglist-Invoice101.pps”; nocase; distance:0; fast_pattern; pcre:”/Content-Dispositionx3ax20attachmentx3b[x20trn]+?(?:file)*?name=x22*?Packinglist-Invoice101.ppsx22*?/im”; reference:cve,2014-4114; reference:msb,MS14-060; reference:url,researchcenter.paloaltonetworks.com/2015/06/keybase-keylogger-malware-family-exposed/; reference:url,www.fidelissecurity.com/sites/default/files/FTA_1017_Phishing_in_Plain_Sight-Body-FINAL.pdf; reference:url,www.fidelissecurity.com/sites/default/files/FTA_1017_Phishing_in_Plain_Sight-Appendix-FINAL.pdf;)
NanoCore	alert tcp any any -> any any (msg:”HTTP Client Header contains ‘Host|3a 20|frankief hopto me’ (GenericKD/Kazy/NanoCore/Recam)”; sid:1; rev:1; flow:established,to_server; content:”Host|3a 20|frankief|2e|hopto|2e|me|0d 0a|”; http_header; fast_pattern:only;  metadata:service http;)
NanoCore	alert tcp any any -> any any (msg:”HTTP GET URI contains ‘FAD00979338′”; sid:1; rev:1; flow:established,to_server; content:”GET”; http_method; content:”getPluginName.php?PluginID=FAD00979338″; fast_pattern; http_uri; metadata:service http;)
Qakbot	alert tcp any any -> any any (msg:”HTTP URI GET /t?v=2&c= (Qakbot)”; sid:1; rev:1; flow:established,to_server; content:”/t?v=2&c=”; http_uri; depth:9; fast_pattern; reference:url,www.symantec.com/content/en/us/enterprise/media/security_response/whitepapers/w32_qakbot_in_detail.pdf;)
Qakbot	alert tcp any any -> any 21 (msg:”Possible FTP data exfiltration”; sid:1; rev:1; flow:to_server,established; content:”STOR si_”; content:”.cb”; within:50; reference:url,attack.mitre.org/techniques/T1020; reference:url,www.virustotal.com/en/file/3104ff71bf880bc40d096eca7d1ccc3f762ea6cc89743c6fef744fd76d441d1b/analysis/; metadata:service ftp-ctrlchan;)
Qakbot	alert tcp any any -> any any (msg:”Malicious executable download attempt”; sid:1; rev:1; flow:to_client,established; file_type:MSEXE; file_data; content:”|52 DB 91 CB FE 67 30 9A 8E 72 28 4F 1C A9 81 A1 AA BE AC 8D D9 AB E4 15 EF EA C6 73 89 9F CF 2E|”; fast_pattern:only; reference:url,virustotal.com/#/file/ad815edc045c779628db3a3397c559ca08f012216dfac4873f11044b2aa1537b/detection; metadata:service http;)
Qakbot	alert tcp any any -> any any (msg:”HTTP POST URI contains ‘odin/si.php?get&'”; sid:1; rev:1; flow:to_server,established; content:”/odin/si.php?get&”; fast_pattern:only; http_uri; content:”news_slist”; http_uri; content:”comp=”; http_uri;  reference:url,www.virustotal.com/en/file/478132b5c80bd41b8c11e5ed591fdf05d52e316d40f7c4abf4bfd25db2463dff/analysis/1464186685/; metadata:service http;)
Qakbot	alert tcp any any -> any any (msg:”HTTP URI contains ‘/random750x750.jpg?x='”; sid:1; rev:1; flow:to_server,established; content:”/random750x750.jpg?x=”; fast_pattern:only; http_uri; content:”&y=”; http_uri; content:”Accept|3a 20|application/x-shockwave-flash, image/gif, image/jpeg, image/pjpeg, */*|0d 0a|”; http_header; content:”Cache-Control|3a 20|no-cache|0d 0a|”; http_header; content:!”Accept-“; http_header; content:!”Referer”; http_header;  reference:url,www.virustotal.com/en/file/1826dba769dad9898acd95d6bd026a0b55d0a093a267b481695494f3ab547088/analysis/1461598351/; metadata:service http;)
Qakbot	alert tcp any any -> any any (msg:”HTTP URI contains ‘/datacollectionservice.php3′”; sid:1; rev:1; flow:to_server,established; content:”/datacollectionservice.php3″; fast_pattern:only; http_uri; metadata:service http;)
Qakbot	alert tcp any any -> any any (msg:”HTTP header contains ‘Accept|3a 20|application/x-shockwave-flash, image/gif, image/jpeg, image/pjpeg, */*|0d 0a|'”; sid:1; rev:1; flow:to_server,established; urilen:30<>35,norm; content:”btst=”; http_header; content:”snkz=”; http_header; content:”Accept|3a 20|application/x-shockwave-flash, image/gif, image/jpeg, image/pjpeg, */*|0d 0a|”; fast_pattern:only; http_header; content:”Cache-Control|3a 20|no-cache|0d 0a|”; http_header; content:!”Connection”; http_header; content:!”Referer”; http_header;  reference:url,www.virustotal.com/en/file/1826dba769dad9898acd95d6bd026a0b55d0a093a267b481695494f3ab547088/analysis/1461598351/; metadata:service http;)
Qakbot	alert tcp any any -> any 21 (msg:”Possible ps_dump FTP exfil”; sid:1; rev:1; flow:to_server,established; content:”ps_dump”; fast_pattern:only; pcre:”/ps_dump_[^_]+_[a-z]{5}d{4}x2Ekcb/smi”;  reference:url,www.threatexpert.com/report.aspx?md5=8171d3223f89a495f98c4e3a65537b8f; metadata:service ftp;)
Qakbot	alert tcp any any -> any 21 (msg:”Possible seclog FTP exfil”; sid:1; rev:1; flow:to_server,established; content:”seclog”; fast_pattern:only; pcre:”/seclog_[a-z]{5}d{4}_d{10}x2Ekcb/smi”;  reference:url,www.threatexpert.com/report.aspx?md5=8171d3223f89a495f98c4e3a65537b8f; metadata:service ftp;)
Qakbot	alert tcp any any -> any any (msg:”HTTP URI contains ‘/cgi-bin/jl/jloader.pl'”; sid:1; rev:1; flow:to_server,established; content:”/cgi-bin/jl/jloader.pl”; fast_pattern:only; http_uri;  reference:url,www.threatexpert.com/report.aspx?md5=8171d3223f89a495f98c4e3a65537b8f; metadata:service http;)
Qakbot	alert tcp any any -> any any (msg:”HTTP URI contains ‘/cgi-bin/clientinfo3.pl'”; sid:1; rev:1; flow:to_server,established; content:”/cgi-bin/clientinfo3.pl”; fast_pattern:only; http_uri;  reference:url,www.threatexpert.com/report.aspx?md5=8171d3223f89a495f98c4e3a65537b8f; metadata:service http;)
Qakbot	alert tcp any any -> any any (msg:”HTTP URI contains ‘/u/updates.cb'”; sid:1; rev:1; flow:to_server,established; content:”/u/updates.cb”; fast_pattern:only; http_uri; pcre:”/^Hostx3A[^rn]+((upd+)|(adserv))/Hmi”; reference:url,www.threatexpert.com/report.aspx?md5=8171d3223f89a495f98c4e3a65537b8f; metadata:service http;)
Qakbot	alert tcp any any -> any any (msg:”HTTP response content contains ‘|47 65 74 46 69 6C 65 46 72 6F 6D 52 65 73 6F 75 72 63 65 73 28 29 3A 20 4C 6F 61 64 52 65 73 6F 75 72 63 65 28 29 20 66 61 69 6C 65 64|'”; sid:1; rev:1; flow:to_client,established; file_data; content:”|47 65 74 46 69 6C 65 46 72 6F 6D 52 65 73 6F 75 72 63 65 73 28 29 3A 20 4C 6F 61 64 52 65 73 6F 75 72 63 65 28 29 20 66 61 69 6C 65 64|”; fast_pattern:only; content:”|47 65 74 46 69 6C 65 46 72 6F 6D 52 65 73 6F 75 72 63 65 73 28 29 3A 20 43 72 65 61 74 65 46 69 6C 65 28 29 20 66 61 69 6C 65 64|”; content:”|52 75 6E 45 78 65 46 72 6F 6D 52 65 73 28 29 20 73 74 61 72 74 65 64|”; content:”|73 7A 46 69 6C 65 50 61 74 68 3D|”; content:”|5C 25 75 2E 65 78 65|”; reference:url,www.virustotal.com/en/file/23e72e8b5e7856e811a326d1841bd2ac27ac02fa909d0a951b0b8c9d1d6aa61c/analysis; metadata:service ftp-data,service http;)
Qakbot	alert tcp any any -> any any (msg:”HTTP POST URI contains ‘v=3&c='”; sid:1; rev:1; flow:to_server,established; content:”/t”; http_uri; content:”POST”; http_method; content:”v=3&c=”; depth:6; http_client_body; content:”==”; within:2; distance:66; http_client_body;  reference:url,www.virustotal.com/en/file/3104ff71bf880bc40d096eca7d1ccc3f762ea6cc89743c6fef744fd76d441d1b/analysis/; metadata:service http;)
Qakbot	alert tcp any any -> any any (msg:”HTTP URI GET contains ‘/<alpha>/595265.jpg'”; sid:1; rev:1; flow:established,to_server; content:”/595265.jpg”; http_uri; fast_pattern:only; content:”GET”; nocase; http_method; pcre:”/^/[a-z]{5,15}/595265.jpg$/U”;  reference:url,www.virustotal.com/gui/file/3104ff71bf880bc40d096eca7d1ccc3f762ea6cc89743c6fef744fd76d441d1b/detection; metadata:service http;)
Remcos	alert tcp any any -> any any (msg:”Non-Std TCP Client Traffic contains ‘|1b 84 d5 b0 5d f4 c4 93 c5 30 c2|’ (Checkin #23)”; sid:1; rev:1; flow:established,to_server; dsize:<700; content:”|1b 84 d5 b0 5d f4 c4 93 c5 30 c2|”; depth:11; fast_pattern; content:”|da b1|”; distance:2; within:2;  reference:url,blog.trendmicro.com/trendlabs-security-intelligence/analysis-new-remcos-rat-arrives-via-phishing-email/; reference:url,isc.sans.edu/forums/diary/Malspam+using+passwordprotected+Word+docs+to+push+Remcos+RAT/25292/; reference:url,www.malware-traffic-analysis.net/2019/09/03/index.html; reference:url,www.malware-traffic-analysis.net/2017/10/27/index.html;)
TrickBot	alert tcp any any -> any any (msg:”HTTP Client Header contains ‘host|3a 20|tpsci.com'”; sid:1; rev:1; flow:established,to_server; content:”host|3a 20|tpsci.com”; http_header; fast_pattern:only; metadata:service http;)
TrickBot	alert tcp any any -> any any (msg:”HTTP Client Header contains ‘User-Agent|3a 20|*Loader'”; sid:1; rev:1; flow:established,to_server; content:”User-Agent|3a 20|”; http_header; content:”Loader|0d 0a|”; nocase; http_header; distance:0; within:24; fast_pattern; metadata:service http;)
TrickBot	alert udp any any <> any 53 (msg:”DNS Query/Response onixcellent com (UDP)”; sid:1; rev:1; content:”|0B|onixcellent|03|com|00|”; fast_pattern:only; reference:url,medium.com/stage-2-security/anchor-dns-malware-family-goes-cross-platform-d807ba13ca30; priority:1; metadata:service dns;)
TrickBot	alert tcp any any -> any any (msg:”SSL/TLS Server X.509 Cert Field contains ‘C=XX, L=Default City, O=Default Company Ltd'”; sid:1; rev:2; flow:established,from_server; ssl_state:server_hello; content:”|31 0b 30 09 06 03 55 04 06 13 02|XX”; nocase; content:”|31 15 30 13 06 03 55 04 07 13 0c|Default City”; nocase; content:”|31 1c 30 1a 06 03 55 04 0a 13 13|Default Company Ltd”; nocase; content:!”|31 0c 30 0a 06 03 55 04 03|”;  reference:url,www.virustotal.com/gui/file/e9600404ecc42cf86d38deedef94068db39b7a0fd06b3b8fb2d8a3c7002b650e/detection; metadata:service ssl;)
TrickBot	alert tcp any any -> any any (msg:”SSL/TLS Server X.509 Cert Field contains ‘C=AU, ST=Some-State, O=Internet Widgits Pty Ltd'”; sid:1; rev:1; flow:established,from_server; ssl_state:server_hello; content:”|31 0b 30 09 06 03 55 04 06 13 02|AU”; content:”|31 13 30 11 06 03 55 04 08 13 0a|Some-State”; distance:0; content:”|31 21 30 1f 06 03 55 04 0a 13 18|Internet Widgits Pty Ltd”; distance:0; fast_pattern; content:”|06 03 55 1d 13 01 01 ff 04 05 30 03 01 01 ff|”;  reference:url,www.virustotal.com/gui/file/e9600404ecc42cf86d38deedef94068db39b7a0fd06b3b8fb2d8a3c7002b650e/detection; metadata:service ssl;)
TrickBot	alert tcp any any -> any any (msg:”HTTP Client Header contains ‘boundary=Arasfjasu7′”; sid:1; rev:1; flow:established,to_server; content:”boundary=Arasfjasu7|0d 0a|”; http_header; content:”name=|22|proclist|22|”; http_header; content:!”Referer”; content:!”Accept”; content:”POST”; http_method; metadata:service http;)
TrickBot	alert tcp any any -> any any (msg:”HTTP Client Header contains ‘User-Agent|3a 20|WinHTTP loader/1.'”; sid:1; rev:1; flow:established,to_server; content:”User-Agent|3a 20|WinHTTP loader/1.”; http_header; fast_pattern:only; content:”.png|20|HTTP/1.”; pcre:”/^Hostx3ax20(?:d{1,3}.){3}d{1,3}(?:x3ad{2,5})?$/mH”; content:!”Accept”; http_header; content:!”Referer|3a 20|”; http_header; metadata:service http;)
TrickBot	alert tcp any any -> any any (msg:”HTTP Server Header contains ‘Server|3a 20|Cowboy'”; sid:1; rev:1; flow:established,from_server; content:”200″; http_stat_code; content:”Server|3a 20|Cowboy|0d 0a|”; http_header; fast_pattern; content:”content-length|3a 20|3|0d 0a|”; http_header; file_data; content:”/1/”; depth:3; isdataat:!1,relative; metadata:service http;)
TrickBot	alert tcp any any -> any any (msg:”HTTP URI POST contains C2 Exfil”; sid:1; rev:1; flow:established,to_server; content:”Content-Type|3a 20|multipart/form-data|3b 20|boundary=——Boundary”; http_header; fast_pattern; content:”User-Agent|3a 20|”; http_header; distance:0; content:”Content-Length|3a 20|”; http_header; distance:0; content:”POST”; http_method; pcre:”/^/[a-z]{3}d{3}/.+?.[A-F0-9]{32}/d{1,3}//U”; pcre:”/^Hostx3ax20(?:d{1,3}.){3}d{1,3}$/mH”; content:!”Referer|3a|”; http_header; metadata:service http;)
TrickBot	alert tcp any any -> any any (msg:”HTTP URI GET/POST contains ‘/56evcxv'”; sid:1; rev:1; flow:established,to_server; content:”/56evcxv”; http_uri; fast_pattern:only;  metadata:service http;)
TrickBot	alert icmp any any -> any any (msg:”ICMP traffic conatins ‘hanc'”; sid:1; rev:1; itype:8; icode:0; dsize:22; content:”hanc”; depth:4; fast_pattern; pcre:”/hanc[0-9a-f]{16}../i”;  reference:url,labs.sentinelone.com/anchor-project-for-trickbot-adds-icmp/;)
TrickBot	alert tcp any any -> any any (msg:”HTTP Client Header contains POST with ‘host|3a 20|*.onion.link’ and ‘data='”; sid:1; rev:1; flow:established,to_server; content:”POST”; nocase; http_method; content:”host|3a 20|”; http_header; content:”.onion.link”; nocase; http_header; distance:0; within:47; fast_pattern; file_data; content:”data=”; distance:0; within:5; metadata:service http;)
TrickBot	alert tcp any 80 -> any any (msg:”Non-Std TCP Client Traffic contains PowerView Script Download String”; sid:1; rev:1; flow:established,from_server; content:”PowerView.ps1″; content:”PSReflect/master/PSReflect.psm1″; fast_pattern:only; content:”function New-InMemoryModule”; metadata:service else-ports;)
TrickBot	alert tcp any any -> any 445 (msg:”Non-Std TCP Client SMB Traffic contains ‘44783m8uh77g818_nkubyhu5vfxxbh878xo6hlttkppzf28tsdu5kwppk_11c1jl'”; sid:1; rev:1; flow:established,to_server; content:”44783m8uh77g818_nkubyhu5vfxxbh878xo6hlttkppzf28tsdu5kwppk_11c1jl”; fast_pattern:only; metadata:service netbios-ssn,service and-ports;)
TrickBot	alert tcp any any -> any [80,443,8082] (msg:”Non-Std TCP Client Traffic contains ‘–aksgja8s8d8a8s97′”; sid:1; rev:1; flow:established,to_server; content:”–aksgja8s8d8a8s97″; fast_pattern:only; content:”name=|22|proclist|22|”;  metadata:service else-ports;)
TrickBot	alert tcp any any -> any any (msg:”HTTP Client Header contains ‘User-Agent|3a 20|WinHTTP loader/1.0′”; sid:1; rev:1; flow:established,to_server; content:”User-Agent|3a 20|WinHTTP loader/1.0|0d 0a|”; http_header; fast_pattern:only; pcre:”//t(?:oler|able).png/U”; metadata:service http;)
TrickBot	alert tcp any any -> any [443,8082] (msg:”Non-Std TCP Client Traffic contains ‘_W<digits>.'”; sid:1; rev:1; flow:established,to_server; content:”_W”; fast_pattern:only; pcre:”/_Wd{6,8}./”; metadata:service else-ports;)
TrickBot	alert tcp any [443,447] -> any any (msg:”SSL/TLS Server X.509 Cert Field contains ‘example.com’ (Hex)”; sid:1; rev:1; flow:established,from_server; ssl_state:server_hello; content:”|0b|example.com”; fast_pattern:only; content:”Global Security”; content:”IT Department”; pcre:”/(?:x09x00xc0xb9x3bx93x72xa3xf6xd2|x00xe2x08xffxfbx7bx53x76x3d)/”;  metadata:service ssl,service and-ports;)
TrickBot	alert tcp any any -> any any+F57 (msg:”HTTP URI GET contains ‘/anchor'”; sid:1; rev:1; flow:established,to_server; content:”/anchor”; http_uri; fast_pattern:only; content:”GET”; nocase; http_method; pcre:”/^/anchor_?.{3}/[w_-]+.[A-F0-9]+/?$/U”; metadata:service http;)
TrickBot	alert udp any any <> any 53 (msg:”DNS Query/Response kostunivo com (UDP)”; sid:1; rev:1; content:”|09|kostunivo|03|com|00|”; fast_pattern:only;  reference:url,medium.com/stage-2-security/anchor-dns-malware-family-goes-cross-platform-d807ba13ca30;  metadata:service dns;)
TrickBot	alert udp any any <> any 53 (msg:”DNS Query/Response chishir com (UDP)”; sid:1; rev:1; content:”|07|chishir|03|com|00|”; fast_pattern:only; reference:url,medium.com/stage-2-security/anchor-dns-malware-family-goes-cross-platform-d807ba13ca30; metadata:service dns;)
TrickBot	alert udp any any <> any 53 (msg:”DNS Query/Response mangoclone com (UDP)”; sid:1; rev:1; content:”|0A|mangoclone|03|com|00|”; fast_pattern:only; reference:url,medium.com/stage-2-security/anchor-dns-malware-family-goes-cross-platform-d807ba13ca30; metadata:service dns;)
GootLoader	No signature available.

References

• [1] Malware Tip Card
• [2] Malware Trends
• [3] Agent Telsa
• [4] Agent Tesla Trojan ‘Kneecaps’ Microsoft’s Anti-Malware Interface
• [6] AZORULT Malware Information
• [7] HHS AZORult Malware
• [8] Significant FormBook Distribution Campaigns Impacting the U.S. and South Korea
• [9] FormBook Adds Latest Office 365 0-Day Vulnerability (CVE-2021-40444) to Its Arsenal
• [10] Ursnif Trojan has targeted over 100 Italian banks
• [11] New Variant of Ursnif Continuously Targeting Italy
• [12] URSNIF
• [13] LokiBot trojan malware campaign comes disguised as a popular game launcher
• [14] CISA and MS-ISAC LokiBot Malware
• [15] So Unchill: Melting UNC2198 ICEDID to Ransomware Operations
• [16] Nanocore, Netwire, and AsyncRAT spreading campaign uses public cloud infrastructure
• [18] U.S. Department of Justice: Arkansas Man Sentenced to Prison for Developing and Distributing Prolific Malware
• [19] A closer look at Qakbot’s latest building blocks (and how to knock them down)
• [20] The rise of QakBot
• [21] Remcos Malware Information
• [22] The Latest Remcos RAT Driven By Phishing Campaign
• [23] HHS The Evolution of Ryuk
• [24] CISA Fact Sheet: TrickBot Malware
• [25] Joint CSA Conti Ransomware
• [26] Joint CSA Ransomware Activity Targeting the Healthcare and Public Health Sector
• [27] New Jersey’s Cybersecurity & Communications Integration Cell (NJCCIC) page on GootLooader

Revisions

• August 4, 2022: Initial Version

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