Researchers have uncovered a never-before-seen backdoor written from scratch for methods operating Home windows, macOS, or Linux that remained undetected by nearly all malware scanning engines.
Researchers from safety agency Intezer stated they found SysJoker—the identify they gave the backdoor—on the Linux-based Webserver of a “main instructional establishment.” Because the researchers dug in, they discovered SysJoker variations for each Home windows and macOS as nicely. They believe the cross-platform malware was unleashed within the second half of final yr.
The invention is important for a number of causes. First, absolutely cross-platform malware is one thing of a rarity, with most malicious software program being written for a selected 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 had been a part of a sophisticated risk actor that invested important assets. It’s additionally uncommon for beforehand unseen Linux malware to be present in a real-world assault.
Wardle, in the meantime, stated the .ts extension might 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 had been absolutely 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. Throughout the time the researchers had been analyzing it, the server modified thrice, indicating the attacker was lively and monitoring for contaminated machines.
Based mostly on organizations focused and the malware’s habits, Intezer’s evaluation is that SysJoker is after particular targets, most certainly with the purpose of “espionage along with lateral motion which could additionally result in a ransomware assault as one of many subsequent phases.”