Sandworm (UAC-0165), a Russian hacking group, has been linked to an attack on Ukrainian state networks that involved wiping data from government devices using WinRAR, according to an advisory from the Ukrainian Government Computer Emergency Response Team (CERT-UA).
The attackers accessed critical systems by exploiting VPN accounts lacking multi-factor authentication (MFA). Then, they deleted files from Windows and Linux devices using scripts with the WinRAR archiving program.
How Did the Sandworm Attackers Wipe the Data?
Sandworm attackers used a BAT script while targeting Windows operating systems. The script, called “RoarBAT,” can search disks and specific directories for numerous file types and archive them using WinRAR. The RoarBAT can search for the following file types: .doc, .docx, .rtf, .txt, .xls, .xlsx, .ppt, .pptx, .vsd, .vsdx, .pdf, .png, .jpeg, .jpg, .zip, .rar, .7z, .mp4, .sql, .php, .vbk, .vib, .vrb, .p7s, .sys, .dll, .exe, .bin, and .dat.
The Sandworm attackers utilized the “-df” command-line option while running WinRAR, which led to deleting files as they were archived. Data on the devices were wiped following the deletion of the archives by using the del command combined with the name of the archive file.
According to CERT-UA, the RoarBAT script was distributed to devices on the Windows domain using Group Policy through a scheduled task.
The threat actors used a Bash script on Linux systems, which employed the “dd” utility to overwrite target files with zero bytes, making file recovery unlikely or impossible.
The attackers likely used legitimate programs such as ‘dd’ and WinRAR to avoid detection by security software.
CERT-UA has stated that this incident is similar to a previous destructive attack that targeted the Ukrainian state news agency called “Ukrinform” in January 2023. This attack was also attributed to Sandworm.
The organization notes that the method used to carry out the attack, the IP addresses of the attackers, and the fact that a modified version of RoarBat was used all provide evidence of the similarity between the two incidents.
To protect against cyber attacks, CERT-UA recommends that all critical organizations in the country:
1. Reducing their attack surface
- Patching vulnerabilities
- Disabling unnecessary services
- Restricting access to management interfaces
2. Monitoring their network traffic and logs
3. Protecting VPN accounts with multi-factor authentication
Indicators of Compromise (IoC)
- update1.bat (RoarBat):
- WinRAR.exe (Command line RAR):
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