hello-world-test-mh3PyPI
Advisory published Updated
hello-world-test-mh3 is a confirmed malicious PyPI package (MAL-2026-10908) that steals credentials and exfiltrates sensitive data (malicious version 0.0.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in hello-world-test-mh3 (PyPI)
What this malware does
Package is a trivial hello-world test artifact. setup.py contains an exec(base64.b64decode(...)) call at install time, but the decoded payload is a single print() statement with no network, filesystem, or credential side effects. src/hello_world/init.py defines a _remote_update() function whose urlopen+exec branch is guarded by a constant _SIMULATE_ONLY=True, making the network-fetch-and-exec branch statically unreachable; the reachable branch only execs a local print string. No outbound network occurs, no installer secrets are read, and no attacker-controlled code or destination is referenced. The exec+base64 and import-time fetch-and-exec shapes are present as structural patterns only, with no installer-side harm.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for hello-world-test-mh3 (version 0.0.1).
If you installed it — respond
hello-world-test-mh3 is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If hello-world-test-mh3 was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
- ReversingLabs · finder
Detect & block this
O3 blocks hello-world-test-mh3-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.