claude-internal-utils
This report shows the evidence for claude-internal-utils@9.0.5, the only known version.
OpenSSF/OSV Malicious Advisory
imported 4mo ago · by OpenSSF/OSVOpenSSF/OSV advisory MAL-2026-4525 confirms this npm version as malicious.
Advisory
MAL-2026-4525
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in claude-internal-utils (npm)
Details
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.
References
Source & flagged code
0 flagged · loading sourceNo flagged code excerpts are attached to this scan.
Findings
1 High
HighOsv Malicious Advisory
Affected versions and remediation
This report applies to claude-internal-utils@9.0.5.
The versions list below shows the verdict for each recorded version.
- Avoid installing claude-internal-utils@9.0.5. Remove it from direct dependencies and check your lockfile for transitive copies.
- Choose an independently verified alternative or release. This report does not establish that other versions are safe.
- If this version ran, investigate the affected machine and build environment. Rotate credentials it could access and rebuild from a trusted environment.
Evidence last updated: .
Source advisory published: .
This report uses published external intelligence. The advisory does not provide a separate source-code analysis for each listed version.
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