moonbit-locale-compatPyPI
Advisory published Updated
moonbit-locale-compat is a confirmed malicious PyPI package (MAL-2026-2945) that steals credentials and exfiltrates sensitive data (malicious versions 0.2.1, 0.2.3, 0.2.4). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in moonbit-locale-compat (PyPI)
What this malware does
Campaign includes a chain of dependencies that finally exfiltrate sensitive environment variables to a hardcoded GitHub repository as exfiltration target, and in specific environments also start a reverse shell. It appears to be targeting specifically one GitHub project, where the front-end package was included in a PR.
Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.
Campaign: 2026-04-moonbit-locale-compat
Reasons (based on the campaign):
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The malicious code is intentionally included in a dependency of the package
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The package contains code to create a reverse shell, allowing an attacker to execute any commands on the victim's machine.
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exfiltration-env-variables
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for moonbit-locale-compat (3 malicious versions).
If you installed it — respond
moonbit-locale-compat 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 moonbit-locale-compat 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
- Kamil Mańkowski (kam193) · reporter
- ReversingLabs · finder
Detect & block this
O3 blocks moonbit-locale-compat-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.