Category: alerts

Original release date: February 14, 2023

 

 

 

 

Original release date: February 9, 2023

Summary

Note: This Cybersecurity Advisory (CSA) is part of an ongoing #StopRansomware effort to publish advisories for network defenders that detail various ransomware variants and various ransomware threat actors. These #StopRansomware advisories detail historically and recently 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 about other ransomware threats and no-cost resources.

The United States National Security Agency (NSA), the U.S. Federal Bureau of Investigation (FBI), the U.S. Cybersecurity and Infrastructure Security Agency (CISA), the U.S. Department of Health and Human Services (HHS), the Republic of Korea (ROK) National Intelligence Service (NIS), and the ROK Defense Security Agency (DSA) (hereafter referred to as the “authoring agencies”) are issuing this joint Cybersecurity Advisory (CSA) to highlight ongoing ransomware activity against Healthcare and Public Health Sector organizations and other critical infrastructure sector entities.

This CSA provides an overview of Democratic People’s Republic of Korea (DPRK) state-sponsored ransomware and updates the July 6, 2022, joint CSA North Korean State-Sponsored Cyber Actors Use Maui Ransomware to Target the Healthcare and Public Health Sector. This advisory highlights TTPs and IOCs DPRK cyber actors used to gain access to and conduct ransomware attacks against Healthcare and Public Health (HPH) Sector organizations and other critical infrastructure sector entities, as well as DPRK cyber actors’ use of cryptocurrency to demand ransoms.

The authoring agencies assess that an unspecified amount of revenue from these cryptocurrency operations supports DPRK national-level priorities and objectives, including cyber operations targeting the United States and South Korea governments—specific targets include Department of Defense Information Networks and Defense Industrial Base member networks. The IOCs in this product should be useful to sectors previously targeted by DPRK cyber operations (e.g., U.S. government, Department of Defense, and Defense Industrial Base). The authoring agencies highly discourage paying ransoms as doing so does not guarantee files and records will be recovered and may pose sanctions risks.

For additional information on state-sponsored DPRK malicious cyber activity, see CISA’s North Korea Cyber Threat Overview and Advisories webpage.

Download the PDF version of this report: pdf, 661 kb.

Technical Details

Note: This advisory uses the MITRE ATT&CK for Enterprise framework, version 12. See MITRE ATT&CK for Enterprise for all referenced tactics and techniques.

This CSA is supplementary to previous reports on malicious cyber actor activities involving DPRK ransomware campaigns—namely Maui and H0lyGh0st ransomware. The authoring agencies are issuing this advisory to highlight additional observed TTPs DPRK cyber actors are using to conduct ransomware attacks targeting South Korean and U.S. healthcare systems.

Observable TTPs

The TTPs associated with DPRK ransomware attacks include those traditionally observed in ransomware operations. Additionally, these TTPs span phases from acquiring and purchasing infrastructure to concealing DPRK affiliation:

• Acquire Infrastructure [T1583]. DPRK actors generate domains, personas, and accounts; and identify cryptocurrency services to conduct their ransomware operations. Actors procure infrastructure, IP addresses, and domains with cryptocurrency generated through illicit cybercrime, such as ransomware and cryptocurrency theft.
• Obfuscate Identity. DPRK actors purposely obfuscate their involvement by operating with or under third-party foreign affiliate identities and use third-party foreign intermediaries to receive ransom payments.
• Purchase VPNs and VPSs [T1583.003]. DPRK cyber actors will also use virtual private networks (VPNs) and virtual private servers (VPSs) or third-country IP addresses to appear to be from innocuous locations instead of from DPRK.
• Gain Access [TA0001]. Actors use various exploits of common vulnerabilities and exposures (CVE) to gain access and escalate privileges on networks. Recently observed CVEs that actors used to gain access include remote code execution in the Apache Log4j software library (known as Log4Shell) and remote code execution in various SonicWall appliances [T1190 and T1133]. Observed CVEs used include:
  • CVE 2021-44228
  • CVE-2021-20038
  • CVE-2022-24990

Actors also likely spread malicious code through Trojanized files for “X-Popup,” an open source messenger commonly used by employees of small and medium hospitals in South Korea [T1195].

The actors spread malware by leveraging two domains: xpopup.pe[.]kr and xpopup.com. xpopup.pe[.]kr is registered to IP address 115.68.95[.]128 and xpopup[.]com is registered to IP address 119.205.197[.]111. Related file names and hashes are listed in table 1.

Table 1: Malicious file names and hashes spread by xpopup domains

File Name	MD5 Hash
xpopup.rar	1f239db751ce9a374eb9f908c74a31c9
X-PopUp.exe	6fb13b1b4b42bac05a2ba629f04e3d03
X-PopUp.exe	cf8ba073db7f4023af2b13dd75565f3d
xpopup.exe	4e71d52fc39f89204a734b19db1330d3
x-PopUp.exe	43d4994635f72852f719abb604c4a8a1
xpopup.exe	5ae71e8440bf33b46554ce7a7f3de666

 

• Move Laterally and Discovery [TA0007, TA0008]. After initial access, DPRK cyber actors use staged payloads with customized malware to perform reconnaissance activities, upload and download additional files and executables, and execute shell commands [T1083, T1021]. The staged malware is also responsible for collecting victim information and sending it to the remote host controlled by the actors [TA0010].
• Employ Various Ransomware Tools [TA0040]. Actors have used privately developed ransomware, such as Maui and H0lyGh0st [T1486]. Actors have also been observed using or possessing publically available tools for encryption, such as BitLocker, Deadbolt, ech0raix, GonnaCry, Hidden Tear, Jigsaw, LockBit 2.0, My Little Ransomware, NxRansomware, Ryuk, and YourRansom [T1486]. In some cases, DPRK actors have portrayed themselves as other ransomware groups, such as the REvil ransomware group. For IOCs associated with Maui and H0lyGh0st ransomware usage, please see Appendix B.
• Demand Ransom in Cryptocurrency. DPRK cyber actors have been observed setting ransoms in bitcoin [T1486]. Actors are known to communicate with victims via Proton Mail email accounts. For private companies in the healthcare sector, actors may threaten to expose a company’s proprietary data to competitors if ransoms are not paid. Bitcoin wallet addresses possibly used by DPRK cyber actors include:
  • 1MTHBCrBKYEthfa16zo9kabt4f9jMJz8Rm
  • bc1q80vc4yjgg6umedkut3e9mhehxl4q4dcjjyzh59
  • 1J8spy62o7z2AjQxoUpiCGnBh5cRWKVWJC
  • 16ENLdHbnmDcEV8iqN4vuyZHa7sSdYRh76
  • bc1q3wzxvu8yhs8h7mlkmf7277wyklkah9k4sm9anu
  • bc1q8xyt4jxhw7mgqpwd6qfdjyxgvjeuz57jxrvgk9
  • 1NqihEqYaQaWiZkPVdSMiTbt7dTy1LMxgX
  • bc1qxrpevck3pq1yzrx2pq2rkvkvy0jnm56nzjv6pw
  • 14hVKm7Ft2rxDBFTNkkRC3kGstMGp2A4hk
  • 1KCwfCUgnSy3pzNX7U1i5NwFzRtth4bRBc
  • 16sYqXancDDiijcuruZecCkdBDwDf4vSEC
  • 1N6JphHFaYmYaokS5xH31Z67bvk4ykd9CP
  • LZ1VNJfn6mWjPzkCyoBvqWaBZYXAwn135
  • 1KmWW6LgdgykBBrSXrFu9kdoHz95Fe9kQF
  • 1FX4W9rrG4F3Uc7gJ18GCwGab8XuW8Ajy2
  • bc1qlqgu2l2kms5338zuc95kxavctzyy0v705tpvyc
  • bc1qy6su7vrh7ts5ng2628escmhr98msmzg62ez2sp
  • bc1q8t69gpxsezdcr8w6tfzp3jeptq4tcp2g9d0mwy
  • bc1q9h7yj79sqm4t536q0fdn7n4y2atsvvl22m28ep
  • bc1qj6y72rk039mqpgtcy7mwjd3eum6cx6027ndgmd
  • bc1qcp557vltuu3qc6pk3ld0ayagrxuf2thp3pjzpe
  • bc1ql8wsflrjf9zlusauynzjm83mupq6c9jz9vnqxg
  • bc1qx60ec3nfd5yhsyyxkzkpts54w970yxj84zrdck
  • bc1qunqnjdlvqkjuhtclfp8kzkjpvdz9qnk898xczp
  • bc1q6024d73h48fnhwswhwt3hqz2lzw6x99q0nulm4
  • bc1qwdvexlyvg3mqvqw7g6l09qup0qew80wjj9jh7x
  • bc1qavrtge4p7dmcrnvhlvuhaarx8rek76wxyk7dgg
  • bc1qagaayd57vr25dlqgk7f00nhz9qepqgnlnt4upu
  • bc1quvnaxnpqlzq3mdhfddh35j7e7ufxh3gpc56hca
  • bc1qu0pvfmtxawm8s99lcjvxapungtsmkvwyvak6cs
  • bc1qg3zlxxhhcvt6hkuhmqml8y9pas76cajcu9ltdl
  • bc1qn7a3g23nzpuytchyyteyhkcse84cnylznl3j32
  • bc1qhfmqstxp3yp9muvuz29wk77vjtdyrkff4nrxpu
  • bc1qnh8scrvuqvlzmzgw7eesyrmtes9c5m78duetf3
  • bc1q7qry3lsrphmnw3exs7tkwzpvzjcxs942aq8n0y
  • bc1qcmlcxfsy0zlqhh72jvvc4rh7hvwhx6scp27na0
  • bc1q498fn0gauj2kkjsg35mlwk2cnxhaqlj7hkh8xy
  • bc1qnz4udqkumjghnm2a3zt0w3ep8fwdcyv3krr3jq
  • bc1qk0saaw7p0wrwla6u7tfjlxrutlgrwnudzx9tyw
  • bc1qyue2pgjk09ps7qvfs559k8kee3jkcw4p4vdp57
  • bc1q6qfkt06xmrpclht3acmq00p7zyy0ejydu89zwv
  • bc1qmge6a7sp659exnx78zhm9zgrw88n6un0rl9trs
  • bc1qcywkd7zqlwmjy36c46dpf8cq6ts6wgkjx0u7cn

Mitigations

Note: These mitigations align with the Cross-Sector Cybersecurity Performance Goals (CPGs) developed by CISA and the U.S. National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats, tactics, techniques, and procedures. For more information on the CPGs, including additional recommended baseline protections, see cisa.gov/cpg.

The authoring agencies urge HPH organizations to:

• Limit access to data by authenticating and encrypting connections (e.g., using public key infrastructure certificates in virtual private network (VPN) and transport layer security (TLS) connections) with network services, Internet of Things (IoT) medical devices, and the electronic health record system [CPG 3.3].
• Implement the principle of least privilege by using standard user accounts on internal systems instead of administrative accounts [CPG 1.5], which grant excessive system administration privileges.
• Turn off weak or unnecessary network device management interfaces, such as Telnet, SSH, Winbox, and HTTP for wide area networks (WANs) and secure with strong passwords and encryption when enabled.
• Protect stored data by masking the permanent account number (PAN) when displayed and rendering it unreadable when stored—through cryptography, for example.
• Secure the collection, storage, and processing practices for personally identifiable information (PII)/protected health information (PHI), per regulations such as the Health Insurance Portability and Accountability Act of 1996 (HIPAA). Implementing HIPAA security measures could prevent the introduction of malware to the system [CPG 3.4].
  • Secure PII/ PHI at collection points and encrypt the data at rest and in transit using technologies, such as TLS. Only store personal patient data on internal systems that are protected by firewalls, and ensure extensive backups are available.
  • Create and regularly review internal policies that regulate the collection, storage, access, and monitoring of PII/PHI.
• Implement and enforce multi-layer network segmentation with the most critical communications and data resting on the most secure and reliable layer [CPG 8.1].
• Use monitoring tools to observe whether IoT devices are behaving erratically due to a compromise [CPG 3.1].

In addition, the authoring agencies urge all organizations, including HPH Sector organizations, to apply the following recommendations to prepare for and mitigate ransomware incidents:

• Maintain isolated backups of data, and regularly test backup and restoration [CPG 7.3]. These practices safeguard an organization’s continuity of operations or at least minimize potential downtime from a ransomware incident and protect against data losses.
  • Ensure all backup data is encrypted, immutable (i.e., cannot be altered or deleted), and covers the entire organization’s data infrastructure.
• Create, maintain, and exercise a basic cyber incident response plan and associated communications plan that includes response procedures for a ransomware incident [CPG 7.1, 7.2].
  • Organizations should also ensure their incident response and communications plans include data breach incidents response and notification procedures. Ensure the notification procedures adhere to applicable laws.
  • See the CISA-Multi-State Information Sharing and Analysis Center (MS-ISAC) Joint Ransomware Guide and CISA Fact Sheet Protecting Sensitive and Personal Information from Ransomware-Caused Data Breaches for information on creating a ransomware response checklist and planning and responding to ransomware-caused data breaches.
• Install updates for operating systems, software, and firmware as soon as they are released [CPG 5.1]. Timely patching is one of the most efficient and cost-effective steps an organization can take to minimize its exposure to cybersecurity threats. Regularly check for software updates and end-of-life notifications and prioritize patching known exploited vulnerabilities. Consider leveraging a centralized patch management system to automate and expedite the process.
• If you use Remote Desktop Protocol (RDP), or other potentially risky services, secure and monitor them closely [CPG 5.4].
  • 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 phishing-resistant multifactor authentication (MFA) to mitigate credential theft and reuse [CPG 1.3]. If RDP must be available externally, use a VPN, virtual desktop infrastructure, 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 campaigns, log RDP login attempts, and disable unused remote access/RDP ports [CPG 1.1, 3.1].
  • Ensure devices are properly configured and that security features are enabled. Disable ports and protocols not in use for a business purpose (e.g., RDP Transmission Control Protocol port 3389).
  • Restrict the Server Message Block (SMB) protocol within the network to only access necessary servers and remove or disable outdated versions of SMB (i.e., SMB version 1). Threat actors use SMB to propagate malware across organizations.
  • Review the security posture of third-party vendors and those interconnected with your organization. Ensure all connections between third-party vendors and outside software or hardware are monitored and reviewed for suspicious activity [CPG 5.6, 6.2].
  • Implement application control policies that only allow systems to execute known and permitted programs [CPG 2.1].
  • Open document readers in protected viewing modes to help prevent active content from running.
• Implement a user training program and phishing exercises [CPG 4.3] to raise awareness among users about the risks of visiting websites, clicking on links, and opening attachments. Reinforce the appropriate user response to phishing and spearphishing emails.
• Require phishing-resistant MFA for as many services as possible [CPG 1.3]—particularly for webmail, VPNs, accounts that access critical systems, and privileged accounts that manage backups.
• Use strong passwords [CPG 1.4] and avoid reusing passwords for multiple accounts. See CISA Tip Choosing and Protecting Passwords and National Institute of Standards and Technology (NIST) Special Publication 800-63B: Digital Identity Guidelines for more information.
• Require administrator credentials to install software [CPG 1.5].
• Audit user accounts with administrative or elevated privileges [CPG 1.5] and configure access controls with least privilege in mind.
• Install and regularly update antivirus and antimalware software on all hosts.
• Only use secure networks. Consider installing and using a VPN.
• Consider adding an email banner to messages coming from outside your organizations [CPG 8.3] indicating that they are higher risk messages.
• Consider participating in CISA’s no-cost Automated Indicator Sharing (AIS) program to receive real-time exchange of machine-readable cyber threat indicators and defensive measures.

If a ransomware incident occurs at your organization:

• Follow your organization’s ransomware response checklist.
• Scan backups. If possible, scan backup data with an antivirus program to check that it is free of malware. This should be performed using an isolated, trusted system to avoid exposing backups to potential compromise.
• U.S. organizations: Follow the notification requirements as outlined in your cyber incident response plan. Report incidents to appropriate authorities; in the U.S., this would include the FBI at a local FBI Field Office, CISA at cisa.gov/report, or the U.S. Secret Service (USSS) at a USSS Field Office.
• South Korean organizations: Please report incidents to NIS, KISA (Korea Internet & Security Agency), and KNPA (Korean National Police Agency).
  • NIS (National Intelligence Service)
    • Telephone : 111
    • https://www.nis.go.kr
  • KISA (Korea Internet & Security Agency)
    • Telephone : 118 (Consult Service)
    • https://www.boho.or.kr/consult/ransomware.do
  • KNPA (Korean National Police Agency)
    • Electronic Cybercrime Report & Management System: https://ecrm.police.go.kr/minwon/main
• Apply incident response best practices found in the joint Cybersecurity Advisory, Technical Approaches to Uncovering and Remediating Malicious Activity, developed by CISA and the cybersecurity authorities of Australia, Canada, New Zealand, and the United Kingdom.

Resources

Stairwell provided a YARA rule to identify Maui ransomware, and a Proof of Concept public RSA key extractor at the following link:
https://www.stairwell.com/news/threat-research-report-maui-ransomware/

Request For Information

The FBI is seeking any information that can be shared, to include boundary logs showing communication to and from foreign IP addresses, bitcoin wallet information, the decryptor file, and/or benign samples of encrypted files. As stated above, the authoring agencies discourage paying ransoms. Payment does not guarantee files will be recovered and may embolden adversaries to target additional organizations, encourage other criminal actors to engage in the distribution of ransomware, and/or fund illicit activities. However, the agencies understand that when victims are faced with an inability to function, all options are evaluated to protect shareholders, employees, and customers.

Regardless of whether you or your organization decide to pay a ransom, the authoring agencies urge you to promptly report ransomware incidents using the contact information above.

Acknowledgements

NSA, FBI, CISA, and HHS would like to thank ROK NIS and DSA for their contributions to this CSA.

Disclaimer of endorsement

The information and opinions contained in this document are provided “as is” and without any warranties or guarantees. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favoring by the United States Government, and this guidance shall not be used for advertising or product endorsement purposes.

Trademark recognition

Microsoft Threat Intelligence Center is a registered trademark of Microsoft Corporation. Apache®, Sonicwall, and Apache Log4j are trademarks of Apache Software Foundation. TerraMaster Operating System is a registered trademark of Octagon Systems.

Purpose

This document was developed in furtherance of the authors’ cybersecurity missions, including their responsibilities to identify and disseminate threats, and to develop and issue cybersecurity specifications and mitigations. This information may be shared broadly to reach all appropriate stakeholders.

Appendix A: CVE Details

CVE-2021-44228     CVSS 3.0: 10 (Critical)
Vulnerability Description Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.
Recommended Mitigations Apply patches provided by vendor and perform required system updates.
Detection Methods See vendors’ Guidance For Preventing, Detecting, and Hunting for Exploitation of the Log4j 2 Vulnerability.
Vulnerable Technologies and Versions There are numerous vulnerable technologies and versions associated with CVE-2021-44228. For a full list, please check https://nvd.nist.gov/vuln/detail/CVE-2021-44228.
See https://nvd.nist.gov/vuln/detail/CVE-2021-44228 for more information.

 

CVE-2021-20038     CVSS 3.0: 9.8 (Critical)
Vulnerability Description A Stack-based buffer overflow vulnerability in SMA100 Apache httpd server’s mod_cgi module environment variables allows a remote unauthenticated attacker to potentially execute code as a ‘nobody’ user in the appliance. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances firmware 10.2.0.8-37sv, 10.2.1.1-19sv, 10.2.1.2-24sv and earlier versions.
Recommended Mitigations Apply all appropriate vendor updates Upgrade to: SMA 100 Series – (SMA 200, 210, 400, 410, 500v (ESX, Hyper-V, KVM, AWS, Azure): SonicWall SMA100 build versions 10.2.0.9-41sv or later SonicWall SMA100 build versions 10.2.1.3-27sv or later System administrators should refer to the SonicWall Security Advisories in the reference section to determine affected applications/systems and appropriate fix actions. Support for 9.0.0 firmware ended on 10/31/2021. Customers still using that firmware are requested to upgrade to the latest 10.2.x versions.
Vulnerable Technologies and Versions Sonicwall Sma 200 Firmware 10.2.0.8-37Sv Sonicwall Sma 200 Firmware 10.2.1.1-19Sv Sonicwall Sma 200 Firmware 10.2.1.2-24Sv Sonicwall Sma 210 Firmware 10.2.0.8-37Sv Sonicwall Sma 210 Firmware 10.2.1.1-19Sv Sonicwall Sma 210 Firmware 10.2.1.2-24Sv Sonicwall Sma 410 Firmware 10.2.0.8-37Sv Sonicwall Sma 410 Firmware 10.2.1.1-19Sv Sonicwall Sma 410 Firmware 10.2.1.2-24Sv Sonicwall Sma 400 Firmware 10.2.0.8-37Sv Sonicwall Sma 400 Firmware 10.2.1.1-19Sv Sonicwall Sma 400 Firmware 10.2.1.2-24Sv Sonicwall Sma 500V Firmware 10.2.0.8-37Sv Sonicwall Sma 500V Firmware 10.2.1.1-19Sv Sonicwall Sma 500V Firmware 10.2.1.2-24Sv
See https://nvd.nist.gov/vuln/detail/CVE-2021-20038 for more information.

 

CVE-2022-24990    CVSS 3.x: N/A
Vulnerability Description The TerraMaster OS Unauthenticated Remote Command Execution via PHP Object Instantiation Vulnerability is characterized by scanning activity targeting a flaw in the script enabling a remote adversary to execute commands on the target endpoint. The vulnerability is created by improper input validation of the webNasIPS component in the api.php script and resides on the TNAS device appliances’ operating system where users manage storage, backup data, and configure applications. By exploiting the script flaw a remote unauthenticated attacker can pass specially crafted data to the application and execute arbitrary commands on the target system. This may result in complete compromise of the target system, including the exfiltration of information. TNAS devices can be chained to acquire unauthenticated remote code execution with highest privileges.
Recommended Mitigations Install relevant vendor patches. This vulnerability was patched in TOS version 4.2.30
Vulnerable Technologies and Versions TOS v 4.2.29
See https://octagon.net/blog/2022/03/07/cve-2022-24990-terrmaster-tos-unauthenticated-remote-command-execution-via-php-object-instantiation/ and https://forum.terra-master.com/en/viewtopic.php?t=3030 for more information.

Appendix B: Indicators of Compromise (IOCs)

The IOC section includes hashes and IP addresses for the Maui and H0lyGh0st ransomware variants—as well as custom malware implants assumedly developed by DPRK cyber actors, such as remote access trojans (RATs), loaders, and other tools—that enable subsequent deployment of ransomware. For additional Maui IOCs, see joint CSA North Korean State-Sponsored Cyber Actors Use Maui Ransomware to Target the Healthcare and Public Health Sector.

Table 2 lists MD5 and SHA256 hashes associated with malware implants, RATs, and other tools used by DPRK cyber actors, including tools that drop Maui ransomware files.

Table 2: File names and hashes of malicious implants, RATs, and tools

MD5Hash	SHA256Hash
079b4588eaa99a1e802adf5e0b26d8aa	f67ee77d6129bd1bcd5d856c0fc5314169 b946d32b8abaa4e680bb98130b38e7
0e9e256d8173854a7bc26982b1dde783	—
12c15a477e1a96120c09a860c9d479b3	6263e421e397db821669420489d2d3084 f408671524fd4e1e23165a16dda2225
131fc4375971af391b459de33f81c253	—
17c46ed7b80c2e4dbea6d0e88ea0827c	b9af4660da00c7fa975910d0a19fda0720 31c15fad1eef935a609842c51b7f7d
1875f6a68f70bee316c8a6eda9ebf8de	672ec8899b8ee513dbfc4590440a61023 846ddc2ca94c88ae637144305c497e7
1a74c8d8b74ca2411c1d3d22373a6769	ba8f9e7afe5f78494c111971c39a89111ef 9262bf23e8a764c6f65c818837a44
1f6d9f8fbdbbd4e6ed8cd73b9e95a928	4f089afa51fd0c1b2a39cc11cedb3a4a32 6111837a5408379384be6fe846e016
2d02f5499d35a8dffb4c8bc0b7fec5c2	830207029d83fd46a4a89cd623103ba23 21b866428aa04360376e6a390063570
2e18350194e59bc6a2a3f6d59da11bd8	655aa64860f1655081489cf85b77f72a49 de846a99dd122093db4018434b83ae
3bd22e0ac965ebb6a18bb71ba39e96dc	6b7f566889b80d1dba4f92d5e2fb2f5ef24 f57fcfd56bb594978dffe9edbb9eb
40f21743f9cb927b2c84ecdb7dfb14a6	5081f54761947bc9ce4aa2a259a0bd60b 4ec03d32605f8e3635c4d4edaf48894
4118d9adce7350c3eedeb056a3335346	5b7ecf7e9d0715f1122baf4ce745c5fcd76 9dee48150616753fec4d6da16e99e
43e756d80225bdf1200bc34eef5adca8	afb2d4d88f59e528f0e388705113ae54b7 b97db4f03a35ae43cc386a48f263a0
47791bf9e017e3001ddc68a7351ca2d6	863b707873f7d653911e46885e261380b 410bb3bf6b158daefb47562e93cb657
505262547f8879249794fc31eea41fc6	f32f6b229913d68daad937cc72a57aa452 91a9d623109ed48938815aa7b6005c
5130888a0ad3d64ad33c65de696d3fa2	c92c1f3e77a1876086ce530e87aa9c1f9c bc5e93c5e755b29cad10a2f3991435
58ad3103295afcc22bde8d81e77c282f	18b75949e03f8dcad513426f1f9f3ca209d 779c24cd4e941d935633b1bec00cb
5be1e382cd9730fbe386b69bd8045ee7	5ad106e333de056eac78403b033b89c58 b4c4bdda12e2f774625d47ccfd3d3ae
5c6f9c83426c6d33ff2d4e72c039b747	a3b7e88d998078cfd8cdf37fa5454c45f6c bd65f4595fb94b2e9c85fe767ad47
640e70b0230dc026eff922fb1e44c2ea	6319102bac226dfc117c3c9e620cd99c7e afbf3874832f2ce085850aa042f19c
67f4dad1a94ed8a47283c2c0c05a7594	3fe624c33790b409421f4fa2bb8abfd701d f2231a959493c33187ed34bec0ae7
70652edadedbacfd30d33a826853467d	196fb1b6eff4e7a049cea323459cfd6c0e3 900d8d69e1d80bffbaabd24c06eba
739812e2ae1327a94e441719b885bd19	6122c94cbfa11311bea7129ecd5aea6fae 6c51d23228f7378b5f6b2398728f67
76c3d2092737d964dfd627f1ced0af80	bffe910904efd1f69544daa9b72f2a70fb29 f73c51070bde4ea563de862ce4b1
802e7d6e80d7a60e17f9ffbd62fcbbeb	87bdb1de1dd6b0b75879d8b8aef80b562 ec4fad365d7abbc629bcfc1d386afa6
827103a6b6185191fd5618b7e82da292	—
830bc975a04ab0f62bfedf27f7aca673	—
85995257ac07ae5a6b4a86758a2283d7	—
85f6e3e3f0bdd0c1b3084fc86ee59d19	f1576627e8130e6d5fde0dbe3dffcc8bc9e ef1203d15fcf09cd877ced1ccc72a
87a6bda486554ab16c82bdfb12452e8b	980bb08ef3e8afcb8c0c1a879ec11c41b2 9fd30ac65436495e69de79c555b2be
891db50188a90ddacfaf7567d2d0355d	0837dd54268c373069fc5c1628c6e3d75e b99c3b3efc94c45b73e2cf9a6f3207
894de380a249e677be2acb8fbdfba2ef	—
8b395cc6ecdec0900facf6e93ec48fbb	—
92a6c017830cda80133bf97eb77d3292	d1aba3f95f11fc6e5fec7694d188919555b 7ff097500e811ff4a5319f8f230be
9b0e7c460a80f740d455a7521f0eada1	45d8ac1ac692d6bb0fe776620371fca02b 60cac8db23c4cc7ab5df262da42b78
9b9d4cb1f681f19417e541178d8c75d7	f5f6e538001803b0aa008422caf2c3c2a7 9b2eeee9ddc7feda710e4aba96fea4
a1f9e9f5061313325a275d448d4ddd59	dfdd72c9ce1212f9d9455e2bca5a327c88 d2d424ea5c086725897c83afc3d42d
a452a5f693036320b580d28ee55ae2a3	99b0056b7cc2e305d4ccb0ac0a8a270d3f ceb21ef6fc2eb13521a930cea8bd9f
a6e1efd70a077be032f052bb75544358	3b9fe1713f638f85f20ea56fd09d20a96cd 6d288732b04b073248b56cdaef878
ad4eababfe125110299e5a24be84472e	a557a0c67b5baa7cf64bd4d42103d3b285 2f67acf96b4c5f14992c1289b55eaa
b1c1d28dc7da1d58abab73fa98f60a83	38491f48d0cbaab7305b5ddca64ba41a2b eb89d81d5fb920e67d0c7334c89131
b6f91a965b8404d1a276e43e61319931	—
bdece9758bf34fcad9cba1394519019b	9d6de05f9a3e62044ad9ae66111308ccb9 ed2ee46a3ea37d85afa92e314e7127
c3850f4cc12717c2b54753f8ca5d5e0e	99b448e91669b92c2cc3417a4d9711209 509274dab5d7582baacfab5028a818c
c50b839f2fc3ce5a385b9ae1c05def3a	458d258005f39d72ce47c111a7d17e8c52 fe5fc7dd98575771640d9009385456
cf236bf5b41d26967b1ce04ebbdb4041	60425a4d5ee04c8ae09bfe28ca33bf9e76 a43f69548b2704956d0875a0f25145
d0e203e8845bf282475a8f816340f2e8	f6375c5276d1178a2a0fe1a16c5668ce52 3e2f846c073bf75bb2558fdec06531
ddb1f970371fa32faae61fc5b8423d4b	dda53eee2c5cb0abdbf5242f5e82f4de83 898b6a9dd8aa935c2be29bafc9a469
f2f787868a3064407d79173ac5fc0864	92adc5ea29491d9245876ba0b29573936 33c9998eb47b3ae1344c13a44cd59ae
fda3a19afa85912f6dc8452675245d6b	56925a1f7d853d814f80e98a1c4890b0a6 a84c83a8eded34c585c98b2df6ab19
—	0054147db54544d77a9efd9baf5ec96a80 b430e170d6e7c22fcf75261e9a3a71
—	151ab3e05a23e9ccd03a6c49830dabb9e 9281faf279c31ae40b13e6971dd2fb8
—	1c926fb3bd99f4a586ed476e4683163892 f3958581bf8c24235cd2a415513b7f
—	1f8dcfaebbcd7e71c2872e0ba2fc6db81d6 51cf654a21d33c78eae6662e62392
—	f226086b5959eb96bd30dec0ffcbf0f0918 6cd11721507f416f1c39901addafb
—	23eff00dde0ee27dabad28c1f4ffb8b09e8 76f1e1a77c1e6fb735ab517d79b76
—	586f30907c3849c363145bfdcdabe3e2e4 688cbd5688ff968e984b201b474730
—	8ce219552e235dcaf1c694be122d6339e d4ff8df70bf358cd165e6eb487ccfc5
—	90fb0cd574155fd8667d20f97ac464eca67 bdb6a8ee64184159362d45d79b6a4
—	c2904dc8bbb569536c742fca0c51a766e8 36d0da8fac1c1abd99744e9b50164f
—	ca932ccaa30955f2fffb1122234fb1524f7d e3a8e0044de1ed4fe05cab8702a5
—	f6827dc5af661fbb4bf64bc625c78283ef8 36c6985bb2bfb836bd0c8d5397332
—	f78cabf7a0e7ed3ef2d1c976c1486281f56 a6503354b87219b466f2f7a0b65c4

 

Table 3 lists MD5 and SHA256 hashes are associated with Maui Ransomware files.

Table 3: File names and hashes of Maui ransomware files

MD5 Hash	SHA256 Hash
4118d9adce7350c3eedeb056a3335346	5b7ecf7e9d0715f1122baf4ce745c5fcd76 9dee48150616753fec4d6da16e99e
9b0e7c460a80f740d455a7521f0eada1	45d8ac1ac692d6bb0fe776620371fca02b 60cac8db23c4cc7ab5df262da42b78
fda3a19afa85912f6dc8452675245d6b	56925a1f7d853d814f80e98a1c4890b0a6 a84c83a8eded34c585c98b2df6ab19
2d02f5499d35a8dffb4c8bc0b7fec5c2	830207029d83fd46a4a89cd623103ba232 1b866428aa04360376e6a390063570
c50b839f2fc3ce5a385b9ae1c05def3a	458d258005f39d72ce47c111a7d17e8c52 fe5fc7dd98575771640d9009385456
a452a5f693036320b580d28ee55ae2a3	99b0056b7cc2e305d4ccb0ac0a8a270d3f ceb21ef6fc2eb13521a930cea8bd9f
a6e1efd70a077be032f052bb75544358	3b9fe1713f638f85f20ea56fd09d20a96cd6 d288732b04b073248b56cdaef878
802e7d6e80d7a60e17f9ffbd62fcbbeb	87bdb1de1dd6b0b75879d8b8aef80b562e c4fad365d7abbc629bcfc1d386afa6
—	0054147db54544d77a9efd9baf5ec96a80b 430e170d6e7c22fcf75261e9a3a71

 

Table 4 lists MD5 and SHA256 hashes associated with H0lyGh0st Ransomware files.

Table 4: File names and hashes of H0lyGh0st ransomware files

SHA256 Hash
99fc54786a72f32fd44c7391c2171ca31e72ca52725c68e2dde94d04c286fccd*
F8fc2445a9814ca8cf48a979bff7f182d6538f4d1ff438cf259268e8b4b76f86*
Bea866b327a2dc2aa104b7ad7307008919c06620771ec3715a059e675d9f40af*
6e20b73a6057f8ff75c49e1b7aef08abfcfe4e418e2c1307791036f081335c2d
f4d10b08d7dacd8fe33a6b54a0416eecdaed92c69c933c4a5d3700b8f5100fad
541825cb652606c2ea12fd25a842a8b3456d025841c3a7f563655ef77bb67219
2d978df8df0cf33830aba16c6322198e5889c67d49b40b1cb1eb236bd366826d
414ed95d14964477bebf86dced0306714c497cde14dede67b0c1425ce451d3d7
Df0c7bb88e3c67d849d78d13cee30671b39b300e0cda5550280350775d5762d8

 

MD5 Hash
a2c2099d503fcc29478205f5aef0283b
9c516e5b95a7e4169ecbd133ed4d205f
d6a7b5db62bf7815a10a17cdf7ddbd4b
c6949a99c60ef29d20ac8a9a3fb58ce5
4b20641c759ed563757cdd95c651ee53
25ee4001eb4e91f7ea0bc5d07f2a9744
29b6b54e10a96e6c40e1f0236b01b2e8
18126be163eb7df2194bb902c359ba8e
eaf6896b361121b2c315a35be837576d
e4ee611533a28648a350f2dab85bb72a
e268cb7ab778564e88d757db4152b9fa

* from Microsoft blog post on h0lygh0st

Contact Information

NSA Client Requirements / General Cybersecurity Inquiries: CybersecurityReports@nsa.gov
Defense Industrial Base Inquiries and Cybersecurity Services: DIB_Defense@cyber.nsa.gov
To report incidents and anomalous activity related to information found in this Joint Cybersecurity Advisory, contact CISA’s 24/7 Operations Center at Report@cisa.gov or (888) 282-0870 or your local FBI field office at www.fbi.gov/contact-us/field. When available, please include the following information regarding the incident: date, time, and location of the incident; type of activity; number of people affected; type of equipment used for the activity; the name of the submitting company or organization; and a designated point of contact.

Media Inquiries / Press Desk:

• NSA Media Relations, 443-634-0721, MediaRelations@nsa.gov
• CISA Media Relations, 703-235-2010, CISAMedia@cisa.dhs.gov

Revisions

• February 9, 2023: Initial Version

---

Original release date: February 9, 2023

CISA, the National Security Agency (NSA), the Federal Bureau of Investigation (FBI), the Department of Health and Human Services (HHS), and Republic of Korea’s Defense Security Agency and National Intelligence Service have released a joint Cybersecurity Advisory (CSA), Ransomware Attacks on Critical Infrastructure Fund DPRK Espionage Activities, to provide information on ransomware activity used by North Korean state-sponsored cyber to target various critical infrastructure sectors, especially Healthcare and Public Health (HPH) Sector organizations.

The authoring agencies urge network defenders to examine their current cybersecurity posture and apply the recommended mitigations in this joint CSA, which include:

• Train users to recognize and report phishing attempts.
• Enable and enforce phishing-resistant multifactor authentication. 
• Install and regularly update antivirus and antimalware software on all hosts. 

See Ransomware Attacks on Critical Infrastructure Fund DPRK Espionage Activities for ransomware actor’s tactics, techniques, and procedures, indicators of compromise, and recommended mitigations. Additionally, review StopRansomware.gov for more guidance on ransomware protection, detection, and response.

For more information on state-sponsored North Korean malicious cyber activity, see CISA’s North Korea Cyber Threat Overview and Advisories webpage.

Original release date: February 9, 2023

OpenSSL has released a security advisory to address multiple vulnerabilities affecting OpenSSL versions 3.0.0, 2.2.2, and 1.0.2. An attacker could exploit some of these vulnerabilities to obtain sensitive information.

CISA encourages users and administrators to review the OpenSSL advisory and make the necessary updates.

Original release date: February 8, 2023

Today, CISA and the Federal Bureau of Investigation (FBI) released a joint Cybersecurity Advisory, ESXiArgs Ransomware Virtual Machine Recovery Guidance. This advisory describes the ongoing ransomware campaign known as “ESXiArgs.” Malicious cyber actors may be exploiting known vulnerabilities in unpatched and out-of-service or out-of-date versions of VMware ESXi software to gain access to ESXi servers and deploy ESXiArgs ransomware. The ransomware encrypts configuration files on ESXi servers, potentially rendering virtual machines unusable.

As detailed in the advisory, CISA has created and released an ESXiArgs recovery script at https://github.com/cisagov/ESXiArgs-Recover. CISA and FBI encourage organizations that have fallen victim to ESXiArgs ransomware to consider using the script to attempt to recover their files.

Additionally, CISA and FBI encourage all organizations to review the advisory and incorporate the recommendations for protecting against ESXiArgs ransomware.

Original release date: February 8, 2023

Summary

The Cybersecurity and Infrastructure Security Agency (CISA) and the Federal Bureau of Investigation (FBI) are releasing this joint Cybersecurity Advisory (CSA) in response to the ongoing ransomware campaign, known as “ESXiArgs.” Malicious actors may be exploiting known vulnerabilities in VMware ESXi servers that are likely running unpatched and out-of-service or out-of-date versions of VMware ESXi software to gain access and deploy ransomware. The ESXiArgs ransomware encrypts configuration files on ESXi servers, potentially rendering virtual machines (VMs) unusable. 

CISA has released an ESXiArgs recovery script at github.com/cisagov/ESXiArgs-Recover. Organizations that have fallen victim to ESXiArgs ransomware can use this script to attempt to recover their files. This CSA provides guidance on how to use the script.
ESXiArgs actors have compromised over 3,800 servers globally. CISA and FBI encourage all organizations managing VMware ESXi servers to: 

• Update servers to the latest version of VMware ESXi software, 
• Harden ESXi hypervisors by disabling the Service Location Protocol (SLP) service, and 
• Ensure the ESXi hypervisor is not exposed to the public internet. 

If malicious actors have compromised your organization with ESXiArgs ransomware, CISA and FBI recommend following the script and guidance provided in this CSA to attempt to recover access to your files.  

Download the PDF version of this report: pdf, 712 kb.

Note: CISA and FBI will update this CSA as more information becomes available.
 

Technical Details

Open-source reporting indicates that malicious actors are exploiting known vulnerabilities in VMware ESXi software to gain access to servers and deploy ESXiArgs ransomware. The actors are likely targeting end-of-life ESXi servers or ESXi servers that do not have the available ESXi software patches applied.[1] 

ESXiArgs ransomware encrypts certain configuration files on ESXi servers, potentially rendering VMs unusable. Specifically, the ransomware encrypts configuration files associated with the VMs; it does not encrypt flat files. As a result, it is possible, in some cases, for victims to reconstruct the encrypted configuration files based on the unencrypted flat file. The recovery script documented below automates the process of recreating configuration files. The full list of file extensions encrypted by the malware is: vmdk, vmx, vmxf, vmsd, vmsn, vswp, vmss, nvram, vmem.

RECOVERY GUIDANCE

CISA and FBI do not encourage paying the 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, CISA and FBI urge you to promptly report ransomware incidents to a local FBI Field Office, or to CISA at cisa.gov/report. 

CISA is providing these steps to enable organizations to attempt recovery of their VMs. CISA’s GitHub ESXiArgs recovery script, which also outlines these steps, is available at github.com/cisagov/ESXiArgs-Recover. CISA is aware that some organizations have reported success in recovering files without paying ransoms. CISA’s script is based on findings published by third-party researchers.[2] 

Any organization seeking to use CISA’s ESXiArgs recovery script should carefully review the script to determine if it is appropriate for their environment before deploying it. This script does not seek to delete the encrypted configuration files, but instead seeks to create new configuration files that enable access to the VMs. While CISA works to ensure that scripts like this one are safe and effective, this script is delivered without warranty, either implicit or explicit. Do not use this script without understanding how it may affect your system. CISA does not assume liability for damage caused by this script. Note: Organizations that run into problems with the script can create a GitHub issue at https://github.com/cisagov/ESXiArgs-Recover/issues; CISA will do our best to resolve concerns.

1. Quarantine or take affected hosts offline to ensure that repeat infection does not occur.

2. Download CISA’s recovery script and save it as /tmp/recover.sh.
For example, with wget: wget -O /tmp/recover.sh https://raw.githubusercontent.com/cisagov/ESXiArgs-Recover/main/recover.sh.

3. Give the script execute permissions: chmod +x /tmp/recover.sh

4. Navigate to the folder of a VM you would like to recover and run ls to view the files.
Note: You may browse these folders by running ls /vmfs/volumes/datastore1. For instance, if the folder is called example, run cd /vmfs/volumes/datastore1/example.

5. View files by running ls. Note the name of the VM (via naming convention: [name].vmdk).

6. Run the recovery script with /tmp/recover.sh [name], where [name] is the name of the VM determined previously. 

a. If the VM is a thin format, run /tmp/recover.sh [name] thin.

b. If successful, the recovery script will output that it has successfully run. If unsuccessful, it may not be possible for the recovery script to recover your VMs; consider engaging external incident response help.

7. If the script succeeded, re-register the VM.

a. If the ESXi web interface is inaccessible, remove the ransom note and restore access via the following steps. (Note: Taking the steps below moves the ransom note to the file ransom.html. Consider archiving this file for future incident review.)

• Run cd /usr/lib/vmware/hostd/docroot/ui/ && mv index.html ransom.html && mv index1.html index.html.
• Run cd /usr/lib/vmware/hostd/docroot && mv index.html ransom.html && rm index.html && mv index1.html index.html.
• Reboot the ESXi server (e.g., with the reboot command). After a few minutes, you should be able to navigate to the web interface.

b.    In the ESXi web interface, navigate to the Virtual Machines page.

• If the VM you restored already exists, right click on the VM and select Unregister (see figure 1).

Figure 1: Unregistering the virtual machine.

• Select Create / Register VM (see figure 2).
• Select Register an existing virtual machine (see figure 2).

Figure 2: Registering the virtual machine, selecting machine to register.

• Click Select one or more virtual machines, a datastore or a directory to navigate to the folder of the VM you restored. Select the vmx file in the folder (see figure 3).

Figure 3: Registering the virtual machine, finalizing registration.

• Select Next and Finish. You should now be able to use the VM as normal.

8.    Update servers to the latest software version, disable the Service Location Protocol (SLP) service, and ensure the ESXi hypervisor is not configured to be exposed to the public internet before putting systems back online. 

Additional Incident Response

The above script only serves as a method to recover essential services. Although CISA and FBI have not seen any evidence that the actors have established persistence, we recommend organizations take the following additional incident response actions after applying the script:

1. Review network logging to and from ESXi hosts and the guest VMs for unusual scanning activity.
2. Review traffic from network segments occupied by the ESXi hosts and guests. Consider restricting non-essential traffic to and from these segments.

If you detect activity from the above, implement your incident response plan. CISA and FBI urge you to promptly report ransomware incidents to a local FBI Field Office, or to CISA at cisa.gov/report.

Organizations should also collect and review artifacts, such as running processes/services, unusual authentications, and recent network connections.

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 also encourages 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.  

Additional resources for recovering .vmdk files can be found on a third-party researcher’s website.[2]
 

Mitigations

Note: These mitigations align with the cross-sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats, tactics, techniques, and procedures. For more information on the CPGs, including additional recommended baseline protections, see cisa.gov/cpg.

CISA and FBI recommend all organizations: 

• Temporarily remove connectivity for the associated ESXi server(s).
  • Upgrade your ESXi servers to the latest version of VMware ESXi software [CPG 5.1]. ESXi releases are cumulative, and the latest builds are documented in VMware’s article, Build numbers and versions of VMware ESXi/ESX.
  • Harden ESXi hypervisors by disabling the Service Location Protocol (SLP) service, which ESXiArgs may leverage. For more information on executing workarounds, see VMware’s guidance How to Disable/Enable the SLP Service on VMware ESXi. 
  • Ensure your ESXi hypervisor is not configured to be exposed to the public internet.

In addition, CISA and FBI recommend organizations apply the following recommendations to prepare for, mitigate/prevent, and respond to ransomware incidents.

Preparing for Ransomware

• Maintain offline backups of data, and regularly test backup and restoration [CPG 7.3]. These practices safeguard an organization’s continuity of operations or at least minimize potential downtime from a ransomware incident and protect against data losses.
• Ensure all backup data is encrypted, immutable (i.e., cannot be altered or deleted), and covers the entire organization’s data infrastructure.
• Create, maintain, and exercise a basic cyber incident response plan and associated communications plan that includes response procedures for a ransomware incident [CPG 7.1, 7.2].

 Mitigating and Preventing Ransomware

• Restrict Server Message Block (SMB) Protocol within the network to only access servers that are necessary and remove or disable outdated versions of SMB (i.e., SMB version 1). Threat actors use SMB to propagate malware across organizations.
• Require phishing-resistant MFA for as many services as possible [CPG 1.3]—particularly for webmail, VPNs, accounts that access critical systems, and privileged accounts that manage backups.
• Review the security posture of third-party vendors and those interconnected with your organization. Ensure all connections between third-party vendors and outside software or hardware are monitored and reviewed for suspicious activity.
• Implement allow-listing policies for applications and remote access that only allow systems to execute known and permitted programs.
• Open document readers in protected viewing modes to help prevent active content from running.
• Implement user training program and phishing exercises to raise awareness among users about the risks of visiting suspicious websites, clicking on suspicious links, and opening suspicious attachments. Reinforce the appropriate user response to phishing and spearphishing emails.
• Use strong passwords [CPG 1.4] and avoid reusing passwords for multiple accounts. See CISA Tip Choosing and Protecting Passwords and the NIST’s Special Publication 800-63B: Digital Identity Guidelines for more information.
• Require administrator credentials to install software [CPG 1.5].
• Audit user accounts with administrative or elevated privileges and configure access controls with least privilege in mind [CPG 1.5].
• Install and regularly update antivirus and antimalware software on all hosts.
• Consider adding an email banner to messages coming from outside your organizations.
• Disable hyperlinks in received emails.
• Consider participating in CISA’s no-cost Automated Indicator Sharing (AIS) program to receive real-time exchange of machine-readable cyber threat indicators and defensive measures. 

Responding to Ransomware Incidents

If a ransomware incident occurs at your organization:

• Follow your organization’s Ransomware Response Checklist (see Preparing for Ransomware section).
• Scan backups. If possible, scan backup data with an antivirus program to check that it is free of malware. This should be performed using an isolated, trusted system to avoid exposing backups to potential compromise.
• Follow the notification requirements as outlined in your cyber incident response plan.
• Report incidents to CISA at cisa.gov/report, FBI at a local FBI Field Office, or the U.S. Secret Service (USSS) at a USSS Field Office.
• Apply incident response best practices found in the joint Cybersecurity Advisory, Technical Approaches to Uncovering and Remediating Malicious Activity, developed by CISA and the cybersecurity authorities of Australia, Canada, New Zealand, and the United Kingdom.

Note: CISA and FBI strongly discourage paying ransoms as doing so does not guarantee files and records 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.

Resources 

See Stopransomware.gov, a whole-of-government approach, for ransomware resources and alerts.

ACKNOWLEDGEMENTS

CISA and FBI would like to thank VMware for their contributions to this CSA.
 

References

• VMware Security Response Center (vSRC) Response to ‘ESXiArgs’ Ransomware Attacks – VMware Security Blog
• Enes Sonmez and Ahmet Aykac, YoreGroup Tech Team: decrypt your crypted files in ESXi servers affected by CVE-2020-3992 / CryptoLocker attack

Revisions

• February, 2023: Initial Version

---

Original release date: February 7, 2023

CISA has released a recovery script for organizations that have fallen victim to ESXiArgs ransomware. The ESXiArgs ransomware encrypts configuration files on vulnerable ESXi servers, potentially rendering virtual machines (VMs) unusable.

CISA recommends organizations impacted by ESXiArgs evaluate the script and guidance provided in the accompanying README file to determine if it is fit for attempting to recover access to files in their environment.

Organizations can access the recovery script here: https://github.com/cisagov/ESXiArgs-Recover

Original release date: February 7, 2023