BlackCat, also known as ALPHV, is a Ransomware as a Service - RaaS that has been gaining notoriety since November 2021, has been in the spotlight and has caused major damage to several companies around the world. This ransomware is written in the Rust language and can infect Linux and Windows systems. 

The group stands out for being effective in marketing to its affiliates and for them receiving a generous share of ransom payments, as well as for using double and triple extortion tactics, charging a ransom to decrypt files, threatening to leak them or carrying out attacks DDoS attacks if the ransom is not paid.

MITRE ATT&CK

Some of MITRE's tactics have already been mapped and have identified the most recurrent forms of attack by this group. They are: 

T1027.002	Obfuscated Files or Information: Software Packing
T1027	Obfuscated Files or Information
T1007	System Service Discovery
T1040	Network Sniffing
T1059	Command and Scripting Interpreter
TA0010	Exfiltration
T1082	System Information Discovery
T1133	External Remote Services
T1490	Inhibit System Recovery
T1485	Data Destruction
T1078	Valid Accounts
T1586	Compromise Accounts
T1486	Data Encrypted For Impact
T1590	Gather Victim Network Information
T1592	Gather Victim Host Information
T1140	Encode/Decode Files or Information
T1202	Indirect Command Execution
T1543.003	Create or Modify System Process: Windows Service
T1550.002	Use Alternate Authentication Material: Pass the Hash

IoCs

In addition to hashes and URLs, commands and processes used by the group have also been identified that can help detect this variant of ransomware. Although they are legitimate commands and processes, they are also considered suspicious: 

Commands executed in Linux/VMware ESXi:

• esxcli -formatter=csv -format-param=fields=="WorldID,DisplayName" vm process list | awk -F "\"*,\"*" '{system("esxcli vm process kill -type=force -world-id="$1)}' 
• for i in `vim-cmd vmsvc/getallvms| awk ‘{print$1}’`;do vim-cmd vmsvc/snapshot.removeall $i & done 

Windows commands and processes:

• arp -a  
• %SYSTEM32%\DllHost.exe /Processid:{3E5FC7F9-9A51-4367-9063-A120244FBEC7}  
• for /F \"tokens=*\" %1 in ('wevtutil.exe el') DO wevtutil.exe cl \"%1\""  
• fsutil behavior set SymlinkEvaluation R2L:1  
• fsutil behavior set SymlinkEvaluation R2R:1 
• psexec.exe -accepteula \\<TARGET_HOST> -u <USERNAME> -p <PASSWORD> -s -d -f -c <ALPHV_EXECUTABLE> [FLAGS] [OPTIONS] –access-token <ACCESS_TOKEN> [SUBCOMMAND]
• reg add HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters /v MaxMpxCt /d 65535 /t REG_DWORD /f  
• wmic csproduct get UUID 

URLs - Onion Websites

id7seexjn4bojn5rvo4lwcjgufjz7gkisaidckaux3uvjc7l7xrsiqad[.onion] sty5r4hhb5oihbq2mwevrofdiqbgesi66rvxr5sr573xgvtuvr4cs5yd[.onion] htnpafzbvddr2llstwbjouupddflqm7y7cr7tcchbeo6rmxpqoxcbqqd[.onion] aoczppoxmfqqthtwlwi4fmzlrv6aor3isn6ffaiic55wrfumxslx3vyd[.onion] alphvmmm27o3abo3r2mlmjrpdmzle3rykajqc5xsj7ejksbpsa36ad[.onion] 2cuqgeerjdba2rhdiviezodpu3lc4qz2sjf4qin6f7std2evleqlzjid[.onion] zujgzbu5y64xbmvc42addp4lxkoosb4tslf5mehnh7pvqjpwxn5gokyd[.onion] mu75ltv3lxd24dbyu6gtvmnwybecigs5auki7fces437xvvflzva2nqd[.onion]

HASHES

MD5

b9acf6efedadae53cf015d0aa9f32653 701b4b004eecb69046c210237846d46d fe16fa500584cb241532dc7cb75c1f53 173c4085c23080d9fb19280cc507d28d 5178bd507c07bc2d5274e0947834e48e 9502d64e8f8c0f50127e2a7263596891 cf2264987cc01dc8d3f72027347a968b 07e71cd54f3ac00b2a34c7955e5c41a8 87f9dd02e0c6346e6d1ca3957a83709a 0646491738c76fd6a9eefaed43eabf43

SHA1

087497940a41d96e4e907b6dc92f75f4a38d861a 11203786b17bb3873d46acae32a898c8dac09850 2a53525eeb7b76b3d1bfe40ac349446f2add8784 45212fa4501ede5af428563f8043c4ae40faec76 57a6dfd2b021e5a4d4fe34a61bf3242ecee841b3 5869820f261f76eafa1ba00af582a9225d005c89 5c6ca5581a04955d8e4d1fa452621fbc922ecb7b 655c2567650d2c109fab443de4b737294994f1fd 783b2b053ef0345710cd2487e5184f29116e367c 89060eff6db13e7455fee151205e972260e9522a 9146a448463935b47e29155da74c68d16e0d7031 94f025f3be089252692d58e54e3e926e09634e40 a186c08d3d10885ebb129b1a0d8ea0da056fc362 c1187fe0eaddee995773d6c66bcb558536e9b62c ce5540c0d2c54489737f3fefdbf72c889ac533a9 d65a131fb2bd6d80d69fe7415dc1d1fd89290394 da1e4a09a59565c5d62887e0e9a9f6f04a18b5f4 e17dc8062742878b0b5ced2145311929f6f77abd e22436386688b5abe6780a462fd07cd12c3f3321 f466b4d686d1fa9fed064507639b9306b0d80bbf

SHA256

0c6f444c6940a3688ffc6f8b9d5774c032e3551ebbccb64e4280ae7fc1fac479 13828b390d5f58b002e808c2c4f02fdd920e236cc8015480fa33b6c1a9300e31 15b57c1b68cd6ce3c161042e0f3be9f32d78151fe95461eedc59a79fc222c7ed 1af1ca666e48afc933e2eda0ae1d6e88ebd23d27c54fd1d882161fd8c70b678e 28d7e6fe31dc00f82cb032ba29aad6429837ba5efb83c2ce4d31d565896e1169 2cf54942e8cf0ef6296deaa7975618dadff0c32535295d3f0d5f577552229ffc 38834b796ed025563774167716a477e9217d45e47def20facb027325f2a790d1 3d7cf20ca6476e14e0a026f9bdd8ff1f26995cdc5854c3adb41a6135ef11ba83 4e18f9293a6a72d5d42dad179b532407f45663098f959ea552ae43dbb9725cbf 59868f4b346bd401e067380cac69080709c86e06fae219bfb5bc17605a71ab3f 731adcf2d7fb61a8335e23dbee2436249e5d5753977ec465754c6b699e9bf161 74464797c5d2df81db2e06f86497b2127fda6766956f1b67b0dcea9570d8b683 7b2449bb8be1b37a9d580c2592a67a759a3116fe640041d0f36dc93ca3db4487 7e363b5f1ba373782261713fa99e8bbc35ddda97e48799c4eb28f17989da8d8e bd337d4e83ab1c2cacb43e4569f977d188f1bb7c7a077026304bf186d49d4117 c3e5d4e62ae4eca2bfca22f8f3c8cbec12757f78107e91e85404611548e06e40 c8b3b67ea4d7625f8b37ba59eed5c9406b3ef04b7a19b97e5dd5dab1bd59f283 cefea76dfdbb48cfe1a3db2c8df34e898e29bec9b2c13e79ef40655c637833ae f815f5d6c85bcbc1ec071dd39532a20f5ce910989552d980d1d4346f57b75f89 f8c08d00ff6e8c6adb1a93cd133b19302d0b651afd73ccb54e3b6ac6c60d99c6

Conclusion

Being prepared to face the challenges posed by the various types of cyber threats means being one step ahead. Understanding how certain groups operate is a way of mapping and analyzing the points for improvement that need to be worked on in each company's infrastructure.  

The following recommendations are fundamental to this protection process and are suggested as a starting point for a more secure infrastructure. 

Recommendations

1. keep data backups encrypted and offline and test them frequently.

Backup procedures should be carried out regularly. It is important that they are kept offline, as many ransomware variants try to locate and delete or encrypt accessible backups. 

2. Create, maintain and execute a basic cyber incident response plan, a recovery plan and an associated communications plan. 

• The cyber incident response plan should include response and notification procedures for ransomware incidents. We recommend the CISA and Multi-State Information and Sharing Center (MS-ISAC) Joint Ransomware Guide for more details on creating a cyber incident response plan. 
• The recovery plan should address how to operate if you lose access or control of critical functions. CISA offers no-cost, non-technical cyber resilience assessments to help organizations evaluate their operational resilience and cyber security practices. 

3. Mitigate vulnerabilities and misconfigurations of Internet-facing services to reduce the risk of actors exploiting this attack surface: 

a. Employ best practices for the use of Remote Desktop Protocol (RDP) and other remote desktop services. Threat actors usually gain initial access to a network via exposed and poorly protected remote services and subsequently propagate the ransomware. 

Audit the network for systems using RDP, unused closed RDP ports, apply account locks after a specified number of attempts, apply multi-factor authentication (MFA) and record RDP login attempts. 

 b. Perform regular vulnerability scans to identify and resolve vulnerabilities, especially those in Internet-facing devices. CISA offers a range of free cyber hygiene services, including vulnerability scanning, to help critical infrastructure organizations assess, identify and reduce their exposure to cyber threats such as ransomware. By taking advantage of these services, organizations of any size will receive recommendations on ways to reduce their risks and mitigate attack vectors. 

c. Update software, including operating systems, applications and firmware, in a timely manner. Prioritize timely patching of critical vulnerabilities and vulnerabilities in Internet-facing servers - as well as Internet data processing software, web browsers, browser plug-ins and document readers. If rapid remediation is not feasible, implement mitigations made available by the vendor. 

d. Make sure that the devices are configured correctly and the security features activated; for example, disabling ports and protocols that are not being used for a business purpose. 

e. Disable or block the incoming and outgoing SMB(Server Message Block) protocol and remove or disable outdated versions of SMB. 

4. Reduce the risk of phishing reaching end users: 

a. Enabling spam filters. 

b. Implementing a cybersecurity user awareness and training program that includes guidance on how to identify and report suspicious activity (e.g. phishing) or incidents.  

5. Use the best cybersecurity practices available: 

a. Ensure that all anti-virus, anti-malware and signature software is up to date. 

b. Implementapplication allowlisting. 

c. Ensure that user accounts and privileges are limited through account usage policies, user account control and privileged account management. 

d. Employ MFA for as many services as possible, especially for webmail, virtual private networks (VPNs) and accounts that access critical systems. 

References

1. Mitre Att&ck 
2. The Record 
3. Cisco Talos 
4. Polyswarm 
5. Varonis