A researcher has uncovered one of many extra uncommon finds within the annals of malware: booby-trapped recordsdata that rat out downloaders and attempt to forestall unauthorized downloading sooner or later. The recordsdata can be found on websites frequented by software program pirates.
Vigilante, as SophosLabs Principal Researcher Andrew Brandt is looking the malware, will get put in when victims obtain and execute what they suppose is pirated software program or video games. Behind the scenes, the malware reviews the file title that was executed to an attacker-controlled server, together with the IP handle of the victims’ computer systems. As a completion, Vigilante tries to change the victims’ computer systems to allow them to not entry thepiratebay.com and as many as 1,000 different pirate websites.
Not your typical malware
“It’s actually uncommon to see one thing like this as a result of there’s usually only one motive behind most malware: stealing stuff,” Brandt wrote on Twitter. “Whether or not that’s passwords, or keystrokes, or cookies, or mental property, or entry, and even CPU cycles to mine cryptocurrency, theft is the motive. However not on this case. These samples actually solely did a number of issues, none of which match the standard motive for malware criminals.”
However not on this case. These samples actually solely did a number of issues, none of which match the standard motive for malware criminals.
For one factor, they modify the HOSTS file on the PC so as to add entries. Lots of entries.
That they had a typical theme. pic.twitter.com/O1Z2fSXZ1n
— Accountability Brandt (@threatresearch) June 17, 2021
As soon as victims have executed the trojanized file, the file title and IP handle are despatched within the type of an HTTP GET request to the attacker-controlled 1flchier[.]com, which may simply be confused with the cloud-storage supplier 1fichier (the previous is spelled with an L because the third character within the title as an alternative of an I). The malware within the recordsdata is basically an identical apart from the file names it generates within the internet requests.
Vigilante goes on to replace a file on the contaminated laptop that forestalls it from connecting to The Pirate Bay and different Web locations recognized for use by folks buying and selling pirated software program. Particularly, the malware updates Hosts.txt, a file that pairs a number of area addresses to distinct IP addresses. Because the picture beneath reveals, the malware pairs thepiratebay.com to 127.0.0.1, a special-purpose IP handle, usually referred to as the localhost or loopback handle, that computer systems use to determine their actual IP handle to different programs.
By mapping the domains to the native host, the malware ensures that the pc can not entry the websites. The one approach to reverse the blocking is to edit the Hosts file to take away the entries.
Brandt discovered a number of the trojans lurking in software program packages accessible on a Discord-hosted chat service. He discovered others masquerading as well-liked video games, productiveness instruments, and safety merchandise accessible via BitTorrent.
There are different oddities. Lots of the trojanized executables are digitally signed utilizing a faux code signing instrument. The signatures include a string of randomly generated 18-character uppercase and lowercase letters. The certificates validity started on the day the recordsdata turned accessible and is about to run out in 2039. Moreover, the properties sheets of the executables don’t align with the file title.
When considered via a hex editor, the executables additionally include a racial epithet that’s repeated greater than 1,000 instances adopted by a big, randomly sized block of alphabetical characters.
“Padding out the archive with purposeless recordsdata of random size might merely be carried out to change the archive’s hash worth,” Brandt wrote. “Padding it out with racist slurs informed me all I wanted to find out about its creator.”
Vigilante has no persistence methodology, which means it has no approach to stay put in. Which means individuals who have been contaminated want solely to edit their Hosts file to be disinfected. SophosLabs offers indicators of compromise right here.