Rurktar Malware: An Espionage Tool in Development

A newly discovered spyware family that appears designed for cyber-espionage is still under development, G DATA security researchers say.

Dubbed Rurktar, the tool hasn’t had all of its functionality implemented yet, but G DATA says “it is relatively safe to say [it] is intended for use in targeted spying operations.” The malicious program could be used for reconnaissance operations, as well as to spy on infected computers users, and steal or upload files.

The spyware, researchers say, appears to originate from Russia. Some of its internal error messages are written in Russian and the IP addresses used to remotely control the tool are located in the country, which the security firm considers strong indicators of its origin.

At the moment, Rurktar packs functions that allow it to perform reconnaissance of a network infrastructure and check whether a particular machine is reachable or not, as well as to take screenshots of an infected machine’s desktop, and also download specific files from a target system. Furthermore, the program can delete files from the target machine and can also upload files to it.

“All of this points to industrial espionage – the functions that have been described so far do not have any practical application for large-scale operations, such as ransomware schemes,” G DATA explains.

The malware can also be used to enumerate usernames, computer name, and OS version; get the current preferences the malware is actively using; enumerate the UUID; list hard disks and information about them; execute a command via the command prompt; list current running processes on the computer; and terminate running processes.      

Implemented functions in the configuration file include Debug (writes logfile RCS.log to the disk), Port (the port the malware connects to), IP (the IP the malware connects to), FriendlyID (a default return value being used if no UUID was enumerated), NetworkImageQ (sets the quality of the image to be delivered), CaptureDirectory (checks whether a directory exists or not), and ScreenshotEx (sets the extension type for all screenshots).

A great deal of other functions haven’t been implemented yet: CaptureMode, CaptureStart, CaptureStopProcess1, VideoCap, SkipFrames, DetectionPreBuffer, DefPass, DetectPorog, MaxCaptureFrames, WatchFiles, SendOriginPreviews, ControlExt, WatchProc, ScreenshotAutoCapture, ScreenshotPause, ProxyEnabled, and several others more.

The malware uses a wrapper called Snow.exe, which checks whether admin privileges are available or not and executes Rurktar. It can also execute a new process of itself to ask the user for admin privileges if needed. To gain persistency, the spyware installs a new service called RCSU, which is started upon reboot.

What the security researchers haven’t established yet, however, is whether the espionage tool is the work of a single individual or that of a team. Its author apparently uses a Dropbox folder as a working directory, which could suggest that there are multiple individuals cooperating on building it and are consolidating their work through a Dropbox.

“What Dropbox can also be used for by a single individual is a crude and very basic versioning system – some Dropbox accounts offer the possibility of restoring earlier versions of a file. Therefore, it can be used to track changes, but it is not ideal from a developer’s stand point. Using Dropbox as a backup is, of course, also a possibility to be considered here,” G DATA notes.

Being work-in-progress, the cyber-espionage tool hasn’t spread very widely yet, but that is expected to change as soon as operational status is reached.

The few IP addresses linked to it so far are believed to have been used for testing purposes only. Additionally, the IP addresses used for remote control are expected to see increased diversity and to expand beyond the Russian space, mainly because the actors will start using or repurposing the malware for various operations.

“The Rurktar malware is yet not been found that often, but has the potential to be more popular in the coming months because of the amount of options an attacker has with this malware,” G DATA’s Nathan Stern, who performed a detailed analysis of the malware, notes (PDF).

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