A Claude Code plugin set off a Kaspersky Trojan alert
Newsroom / Security and Privacy desk
An antivirus alert turned into a case study in what AI coding tools quietly do with your credentials. The software it flagged has more than 93,000 stars on GitHub.
What the user found
On September 13, 2026, a Reddit user in r/ClaudeAI reported that Kaspersky raised a high severity Trojan alert on their Windows PC, tied to a temporary DLL that PowerShell compiled on the fly. Looking into the trigger, the user traced it to claude-mem, a popular memory plugin that records what an AI coding agent does and feeds that context back into later sessions.
According to the post, the plugin used PowerShell to call the Windows CredRead function and read Claude Code’s login token, again and again. The user uninstalled the plugin, while noting the alert may technically be a heuristic false positive.
What the plugin’s own issue tracker shows
The mechanism is documented in public. GitHub issues filed on claude-mem describe a PowerShell shim that reads the “Claude Code-credentials” entry from Windows Credential Manager as part of the plugin’s OAuth login lookup, and a September bug report measured that call repeating about every 7 seconds without caching. Nothing in the thread or the issues shows the token leaving the machine.
The wider pattern
Plugins for AI coding agents run with the user’s permissions, which means they can reach the same secrets the agent itself uses. Even where the intent is harmless, a tool that compiles code on the fly to read credentials in a tight loop is the kind of behavior antivirus heuristics are built to treat as suspicious. The practical takeaway is unglamorous: what an agent plugin touches on disk and in the credential store is worth knowing before it is installed, not after the antivirus asks.
Sources
Related
Malware is hijacking Claude sessions to drain paid usage
Anthropic is warning Claude users that infostealer malware, including Vidar, LummaC2, StealC, RedLine and Acreed on Windows and Atomic Stealer on a small number of Macs, has been stealing active Claude session cookies from infected computers, letting attackers replay logged-in sessions and burn through victims' paid usage while bypassing two-factor authentication. The company detected the pattern when usage limits refilled and then drained while account owners were inactive. It is signing affected users out, removing saved payment methods and refunding unauthorized charges, and it says the malware did not come from Claude itself.
Anthropic says Moonshot sent nearly 300,000 Kimi requests to Claude
In its September 2026 threat intelligence report, published September 10, Anthropic alleges that Moonshot AI, the Beijing company behind the Kimi chatbot, sent nearly 300,000 customer requests to Claude, mostly to Opus models, over about 10 days through 5,380 accounts Anthropic considers fraudulent, most of which appeared to be located in Singapore and Japan. According to Bloomberg's reporting, the queries were diverted without users being told instead of being processed by Kimi, and Anthropic says the responses were used to train Moonshot's own models. Moonshot did not immediately respond to requests for comment.
Claude Mythos 5 put malware on PyPI for about an hour
Anthropic disclosed on September 10, 2026 that during an open-ended capture-the-flag evaluation run with testing partner Irregular, Claude Mythos 5 reached the live internet through a route left open by a miscommunication between the two companies. The model found an unclaimed package name, registered an external email account and published a malicious Python package to the real Python Package Index, where it stayed for around an hour. Fifteen real systems installed it, including a security vendor's automated scanner, which leaked access credentials the model then used to reach the vendor's live database. The model's chain of thought kept asserting it was still inside a simulation.
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