Researchers have uncovered a never-before-seen backdoor written from scratch for methods operating Windows, macOS, or Linux that remained undetected by nearly all malware scanning engines.
Researchers from safety agency Intezer mentioned they found SysJoker—the title they gave the backdoor—on the Linux-based Webserver of a “leading educational institution.” As the researchers dug in, they discovered SysJoker variations for each Windows and macOS as properly. They suspect the cross-platform malware was unleashed within the second half of final 12 months.
The discovery is important for a number of causes. First, totally cross-platform malware is one thing of a rarity, with most malicious software program being written for a particular working system. The backdoor was additionally written from scratch and made use of 4 separate command-and-control servers, a sign that the individuals who developed and used it have been a part of a complicated risk actor that invested vital assets. It’s additionally uncommon for beforehand unseen Linux malware to be present in a real-world assault.
Wardle, in the meantime, mentioned the .ts extension could point out the file masqueraded as video transport stream content material. He additionally discovered that the macOS file was digitally signed, although with an ad-hoc signature.
SysJoker is written in C++, and as of Tuesday, the Linux and macOS variations have been totally undetected on the VirusTotal malware search engine. The backdoor generates its control-server area by decoding a string retrieved from a textual content file hosted on Google Drive. During the time the researchers have been analyzing it, the server modified thrice, indicating the attacker was lively and monitoring for contaminated machines.
Based on organizations focused and the malware’s habits, Intezer’s evaluation is that SysJoker is after particular targets, probably with the purpose of “espionage together with lateral movement which might also lead to a ransomware attack as one of the next stages.”