AvosLocker was first detected in 2021, and it usually appears as ransomware targeting Windows systems. After a variant targeting Linux environments emerged, striking attacks began to occur. The group, which operates as a ransomware-as-a-service (RaaS), claims to offer the “fastest service on the market.”
AvosLocker Targets Critical Infrastructure
AvosLocker has a wide range of victims, from retail companies in Asia to educational institutes in the Middle East. In the FBI’sadvisory dated March 17, 2022, it is stated that the group targets victims explicitly from the USA’s Financial Services, Manufacturing, and Government Facilities sectors.
AvosLocker’s Tactics, Techniques, and Procedures
The group steals the victim’s files, encrypting them and demanding a ransom. It uses email campaigns to deliver malicious files. After obtaining RDP access, it replaces the files on the victim’s server with the extensions “.avos,” “.avos2,” or “.avoslinux.” Then leaves the ransom note “GET_YOUR_FILES_BACK.txt” linked to the “.onion” payment site.
The ransomware gang threatens the victims to leak and sell their data in its own leak site if they do not agree to pay the ransom. They get offers by showing previews of stolen data to those who want it.
AvosLocker Malware IoCs
The FBI includes a list of IoCs of AvosLocker in its latest report. In the report, modifying Windows Registry ‘Run’ keys and scheduled tasks are counted among IoCs.
Other tools used in ransomware attacks are as follows:
- Cobalt Strike
- Encoded PowerShell scripts
- PuTTY Secure Copy client tool “pscp.exe.”
- Advanced IP Scanner
Vulnerabilities Exploited by AvosLocker
According to the FBI report, many victims report Microsoft Exchange Server vulnerabilities as an intrusion vector. In addition, specific vulnerabilities are also observed to be exploited by the group. CVE-2021-31207, CVE-2021-34523, and CVE-2021-34473 Proxy Shell vulnerabilities and CVE-2021-26855 are some of them.
How Can SOCRadar Help Avoiding Ransomware?
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