Inside a malicious Claude Code-branded extension and its persistent SSH backdoor
Inside a malicious Claude Code-branded extension and its persistent SSH backdoor
On October 29, 2026, Cursor reported that a tampered copy of Claude Code extension (anthropic.claude-code, versions 2.1.313 and 2.1.312) was available and served in the Cursor extension marketplace for a few hours to attempt a supply-chain attack on Cursor users.
- Tags
- malware
Indicators of compromise
auto-extracted · verify before use · export allAll| Type | Indicator | Context |
|---|---|---|
| ipv4 | 134.209.82.225 | ence of compromise on their own. Indicator Type Description 134.209.82[.]225 IP address Configured remote SSH and HTTP destination hxx |
| sha256 | 7e0a52885fadee05544a9e99eb18c792bec05900a5e1a66d68f8383decb0e278 | ry point; not a Visual Studio extension (VSIX) package hash 7e0a52885fadee05544a9e99eb18c792bec05900a5e1a66d68f8383decb0e278 SHA256 Decoded tunnel private-key file ~/Library/LaunchAgen |
| sha256 | ecb58cb29078d9646ad1dcdbe51526f2d9cfea06be5fb2ab183e8ecc3ab6bf15 | eFileEvents | where Timestamp > ago(30d) | where SHA256 == "ecb58cb29078d9646ad1dcdbe51526f2d9cfea06be5fb2ab183e8ecc3ab6bf15" or FileName in~ ( ".smt", ".smtk", "smt.cmd", "smtk", "sys |
| url | http://134.209.82.225:8099/beacon | .]225 IP address Configured remote SSH and HTTP destination hxxp://134[.]209[.]82[.]225:8099/beacon URL Reconnaissance endpoint; correlate with the confi |
From the original article
11 min read at microsoft.com
Microsoft analyzes a malicious Claude Code–branded extension, its persistent SSH backdoor, and guidance to detect and remediate it. The post Inside a malicious Claude Code-branded extension and its persistent SSH backdoor appeared first on Microsoft Security Blog.
By Microsoft Security Research · microsoft.com
A short excerpt; the article and its images belong to the publisher. Summary, key facts and assessment above are AI-written from the article and can be wrong.