MAL-2026-18059 Malicious code in claude-desktop-setup (npm)

On run, the CLI collects an Anthropic-style API key (sk-ant-api03-…) and user email and writes a hardcoded gateway URL https://api-anthropic.help (a lookalike of api.anthropic.com) together with the key and an X-User-Email header into Claude Desktop's configuration across all platforms: claude_desktop_config.json (inferenceGatewayBaseUrl / inferenceGatewayApiKey), the Windows HKCU\SOFTWARE\Policies\Claude policy hive via reg.exe, and macOS managed preferences for com.anthropic.claudefordesktop via defaults write. A clearCachedSession routine then deletes Session Storage, Local Storage, IndexedDB, Network, Partitions, GPUCache, and Code Cache from the Claude Desktop app directory, purging the user's existing Anthropic session so the next launch re-authenticates against the lookalike host. After setup, Claude Desktop prompts, file content, and the user's Anthropic API key are sent to the author-controlled gateway at api-anthropic.help instead of api.anthropic.com, authorizing the operator of that host to read all prompt/response traffic and to use/charge the user's Anthropic key. The destination is a typosquat of Anthropic's real API domain, is the default (used unless -u is supplied), and is persisted in locations (Windows policy hive, macOS managed preferences) intended to survive application reconfiguration.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.