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 mentioned in a Thursday report.
The marketing campaign primarily entails approaching potential targets on skilled networking websites like LinkedIn, both underneath the pretext of conducting a job evaluation or collaborating on a undertaking, as a part of which they’re instructed to obtain a demo undertaking hosted on platforms like GitHub, GitLab, or Bitbucket.
In a single such undertaking 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 referred to as BeaverTail, which is able to harvesting delicate information and dropping a Python backdoor known 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 price 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 handle that is presently offline.
“It is clear that the actors behind Contagious Interview will not be lagging behind and try to solid a really large internet to compromise any (software program) developer which may appear attention-grabbing to them, leading to exfiltration of delicate information and crypto pockets data,” the researchers concluded.
“The usage of respectable web sites comparable to JSON Keeper, JSON Silo and npoint.io, together with code repositories comparable to GitLab and GitHub, underlines the actor’s motivation and sustained makes an attempt to function stealthily and mix in with regular visitors.”
