npm

claude-internal-utils @9.0.5

Vulnerability report · Last retrieved from osv.dev July 19, 2026 at 3:07 AM UTC

Malicious

OSV ID

MAL-2026-4525

Ecosystem

npm

Summary

Package name impersonates an internal Anthropic 'claude-*' namespace and the description field self-identifies as 'Alex Birsan Style' dependency-confusion bait. The package ships no library code; its only effect is a postinstall lifecycle hook that runs an inline node one-liner which fetches the installer's public IP from api.ipify.org, executes id || ver && whoami && hostname via child_process.exec, and POSTs hostname, cwd, USERDOMAIN/COMPANY env vars, public IP, package name, and the command output as JSON to a hardcoded attacker subdomain at lszakfghwnvxspyfcmaabd1css99rnq3w.oast.fun (an out-of-band interaction service commonly used for exfiltration). Fires automatically on npm install , before any consumer code runs.

Source: amazon-inspector (24a94a290c15f2b6cdaf351590455cd597bb2881f7bbcf1609fbfbd8031e491f)

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