Threats · 4h ago
OpenSourceMalware disclosed that Anthropic’s official Claude Code for VS Code extension, version 2.1.313, was compromised to install an SSH backdoor. Anthropic had removed it and published version 2.1.314 by Oct. 30, 2026; how the compromise happened remains unknown.
The extension added an attacker-controlled key to `authorized_keys`, the file that controls SSH logins, labeling it “svc-telemetry,” and installed separate startup tasks. It also sent host details to the attacker. Cursor said enabling SSH often failed on Windows and macOS without admin rights, but the key, persistence, and data collection could still remain.
For any developer machine that ran 2.1.313, installing the clean extension does not show that the host is clean. The same gap matters wherever trusted editor add-ons can change login or startup state.
2 sources covering this story
Claude Code extension poisoned with persistent SSH backdoor - Help Net Security
A tampered Claude Code extension on Open VSX planted an SSH backdoor and sent developer data to the attacker.
Official Claude Code VS Code Extension Compromised to Install Persistent SSH Backdoor
A compromised Claude Code VS Code extension added an SSH key, installed persistence, and sent host details before version 2.1.314 replaced it.
Part of the PlainSec briefing for 2026-10-30