The Varonis Threat Labs team found a critical one-click exploit named SearchLeak that turns Microsoft Copilot into a silent data-stealing weapon. The three-stage attack combines older and newer techniques that, chained together, steal sensitive information.
As debate continues over Fable and Mythos restrictions, SearchLeak shows how AI can create and expose novel on-ramps into enterprise systems and quietly leak critical information.
SearchLeak follows our discovery of a dangerous Microsoft Copilot Personal vulnerability, Reprompt, in January.
The Varonis Threat Labs team have worked hand in hand with Microsoft to responsibly disclose SearchLeak. They gave it a max severity level of “critical” and assigned it CVE-2026-42824. We have just been cleared by Microsoft to publish.
Watch an expert walk through the attack in this short video: https://varonis.wistia.com/s/z5q0yct8vxwi7gt and read the full report here: https://www.varonis.com/blog/searchleak
StealC is back with a RAT
Posted in Commentary with tags Varonis on October 22, 2026 by itnerdRemember StealC, the infostealer Europol took down in June during Operation Endgame? Its seller just came back: They’ve just started selling Stadia, a RAT that reuses StealC’s code byte for byte.
The Varonis Threat Labs team bought the build the day it listed. Stadia can control a hidden desktop and run commands, and StealC’s stealer is still in there as one of six modules. The seller is even offering returning customers a free month to come back.
Varonis just published this blog post: https://www.varonis.com/blog/stealc-returns
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