The North Korean risk actors behind the Contagious Interview marketing campaign have as soon as once more tweaked their ways by utilizing JSON storage companies to stage malicious payloads.
“The risk actors have not too long ago resorted to using JSON storage companies like JSON Keeper, JSONsilo, and npoint.io to host and ship malware from trojanized code tasks, with the lure,” NVISO researchers Bart Parys, Stef Collart, and Efstratios Lontzetidis stated in a Thursday report.
The marketing campaign basically entails approaching potential targets on skilled networking websites like LinkedIn, both underneath the pretext of conducting a job evaluation or collaborating on a mission, as a part of which they’re instructed to obtain a demo mission hosted on platforms like GitHub, GitLab, or Bitbucket.
In a single such mission noticed by NVISO, it has been discovered {that a} file named “server/config/.config.env” incorporates a Base64-encoded worth that masquerades as an API key, however, in actuality, is a URL to a JSON storage service like JSON Keeper the place the next-stage payload is saved in obfuscated format.
The payload is a JavaScript malware often called BeaverTail, which is able to harvesting delicate information and dropping a Python backdoor referred to as InvisibleFerret. Whereas the performance of the backdoor has remained largely unchanged from when it was first documented by Palo Alto Networks in late 2023, one notable change entails fetching a further payload dubbed TsunamiKit from Pastebin.
It is value noting that use of TsunamiKit as a part of the Contagious Interview marketing campaign was highlighted by ESET again in September 2025, with the assaults additionally dropping Tropidoor and AkdoorTea. The toolkit is able to system fingerprinting, information assortment, and fetching extra payloads from a hard-coded .onion deal with that is at the moment offline.
“It is clear that the actors behind Contagious Interview aren’t lagging behind and try to solid a really huge internet to compromise any (software program) developer which may appear fascinating to them, leading to exfiltration of delicate information and crypto pockets data,” the researchers concluded.
“Using authentic web sites similar to JSON Keeper, JSON Silo and npoint.io, together with code repositories similar to GitLab and GitHub, underlines the actor’s motivation and sustained makes an attempt to function stealthily and mix in with regular site visitors.”
