New RURansom Wiper Targets Russia
We analyze RURansom, a malware variant discovered to be targeting Russia. Originally suspected to be a ransomware because of its name, analysis reveals RURansom to be a wiper.
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A conflict in cyberspace is unfolding parallel to the conflict between Russia and Ukraine on the ground. Cyberattacks are being lobbed against both Russian and Ukrainian sides, with a new wiper directed against Russia joining the fray.
On March 1, a tweet from MalwareHunterTeam about a possible ransomware variant caught our attention and set our immediate analysis into motion. We found several additional samples of this malware, which has been dubbed as “RURansom” by its developer. Despite its name, analysis has revealed it to be a wiper and not a ransomware variant because of its irreversible destruction of encrypted files.
Based on our telemetry, we have not yet observed active targets for this malware family. One possible reason for this is that the wiper has only targeted a few entries in Russia so far.
RURansom’s code, however, makes its author’s motives clear. Figure 1 shows the code variable responsible for the malware’s ransom note.
The note reads in English as follows:
On February 24, President Vladimir Putin declared war on Ukraine.", "To counter this, I, the creator of RU_Ransom, created this malware to harm Russia. You bought this for yourself, Mr. President.", "There is no way to decrypt your files. No payment, only damage. And yes, this is \"peacekeeping\" like Vladi Papa does, killing innocent civilians", "And yes, it was translated from Bangla into Russian using Google Translate... (This is a direct translation.)
We detected different versions of the malware between February 26 and March 2, 2022. Upon further analysis, we have learned more details about its capabilities.
RURansom: A new wiper
The malware is written in .NET programming language and spreads as a worm by copying itself under the file name "Россия-Украина_Война-Обновление.doc.exe" to all removable disks and mapped network shares. Translated into English, the file name reads as “Russia-Ukraine_War-Update.doc.exe.”
After successfully spreading, the malware then begins encryption. If the assigned disk letter is “C:\,” for example, the files in the folder “C:\\Users\\<UserName>" are encrypted. For other removable and mapped network drives, all files that recursively branch from the root directory are encrypted.
Encryption is applied to all file extensions except for “.bak” files, which are deleted. The files are encrypted with a randomly generated key with length equal to base64 ("FullScaleCyberInvasion + " + MachineName).
The encryption algorithm is AES-CBC using a hard-coded salt. The keys are unique for each encrypted file and are not stored anywhere, making the encryption irreversible and marking the malware as a wiper rather than a ransomware variant.
The “ransom” note, which is the file “Полномасштабное_кибервторжение.txt” (translated as “Full-blown_cyber-invasion.txt”), is then dropped into each directory. However, it is more accurate to say that this is a wiper note.
As seen in the code in Figure 1, the note states its developer’s sentiments and also reveals that the author used Google Translate to convey their message in Russian from the original Bangla.
Still in development
We have discovered several versions of RURansom. Some of these versions check if the IP address where the software is launched is in Russia. In cases where the software is launched outside of Russia, these versions will stop execution, showing a conscious effort to target only Russian-based computers. While most samples were unobfuscated, we found one version using ConfuserEx for obfuscation.
Other versions also attempt to start the process with elevated privileges. These different versions and modifications might indicate that the malware was still undergoing development at the time of writing.
Other activities from the same author
Aside from RURansom, the developer appears to have been working on another “wiper” dubbed as “dnWipe.” Its payload is executed every Tuesday.
We analyzed dnWipe and found that it simply encodes content in base64 for the following file extensions: .doc, .docx, .png, .gif, .jpeg, .jpg, .mp4, .txt, .flv, .mp3, .ppt, .pptx, .xls, and .xlsx. Therefore, just as RURansom is not really a ransomware variant, dnWipe also cannot be classified as an example of a wiper malware because its encoding can be decoded easily.
Other binaries that we can attribute with high confidence to the same developer indicate their other interests. For one, they have also compiled a downloader for an XMRig binary, showing an inclination for cryptocurrency mining.
No one can be indifferent to the conflict between Ukraine and Russia. People all over the world are actively taking sides, and malware developers are no exception.
As this blog entry shows, the exchange of attacks in cyberspace is reflective of this conflict: Leaks have exposed Russian-based cybercriminal groups behind Conti and TrickBot, while a destructive wiper has attacked organizations in Ukraine. Now, the RURansom wiper is seeking out Russian targets.
We see RURansom as just one attempt among a growing list of attacks that aim to support a position espoused strongly by an individual or a group. While we have not yet found any victims of this malware, seeing the evolution in its code leads us believe that its developer will keep updating their malware in an effort to deal some form of damage on Russia.
In general, the tense geopolitical situation has added an edge to cyberattacks. Ultimately, keeping defenses up, staying vigilant against misinformation, and monitoring the situation is essential in order to navigate this uncertain state of affairs.
For more guidance on managing today’s cyber risks, please see our earlier blog post here.
Indicators of Compromise (IOCs)