cas-basePyPI
Advisory published Updated
cas-base is a confirmed malicious PyPI package (MAL-2025-193014) that steals credentials and exfiltrates sensitive data (malicious versions 1.5.2, 1.5.3, 1.5.5…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in cas-base (PyPI)
What this malware does
The package contains code to install remotely stored malware and ensure its persistence. The code is not triggered automatically; it requires a separate trigger.
Originally, cas-base was detected in 2025-07 with an unclear payload. Later it got updated to a clearly malicious payload
Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.
Campaign: 2025-07-cas-base
Reasons (based on the campaign):
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Downloads and executes a remote executable.
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malware
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persistence
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for cas-base (15 malicious versions).
If you installed it — respond
cas-base 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 cas-base 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
Detect & block this
O3 blocks cas-base-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.