Gootkit returned in parallel with REvil ransomware
A year later, Gootkit came back to life with REvil Ransomware, a new campaign targeting Germany.
Last year, the creators of Gootkit leaked data when they left a MongoDB database exposed on the Internet. Following this incident, security investigators believed that the creators of Gootkit had ceased operations until they suddenly appeared in November.
Gootkit comes to life with ransomware collaboration
In this new malicious campaign, hackers hack into WordPress sites and use infected SEO to display fake forum posts. These posts pretend to be a question, with a link to fake forms or downloads.
When the user clicks on the link, they will download a ZIP file containing an obscure JS file that will install either the Gootkit malware or the REvil ransomware.
This same distribution method was previously used by REvil in September 2019, around the same time that Gootkit disappeared.
Gootkit and REvil were installed in anonymous attacks
In Malwarebytes' analysis, this payload is usually Gootkit, although in some cases it was REvil ransomware.
These payloads will be stored as Base64 encoded or hexadecimal strings in either a text file or split into multiple Windows registry values, as shown below.
The loader will eventually read the Registry or the payloads of the text file, decode it and start the process directly in memory.
Using obscure payloads and splits stored in the Registry makes it more difficult for security software to detect malicious payloads.
"The hackers behind this campaign are using a very clever loader that performs certain steps to avoid detection. "Because the payload is stored in the registry with a random key name, many security products will not be able to detect it and remove it," explains Malwarebytes.
An interesting finding the analyst made while testing this malicious campaign was that the Revil infection showed ransom notes used in previous attacks.
- TheAnalyst (@ffforward) November 24
This error was most likely caused by the distribution campaign, which uses an older version of REvil ransomware and forgot to update it to a newer version.