hmacsync

GHSA-93x2-rq2m-926g

Malicious code in hmacsync (PyPI)

Details

**Severity:** Critical

**Affected versions:** `= 1.0.0`

## Source: kam193 (d361ffcded0fc3d88b5095d800b13b3f8a07a581e8003c30bfcf9887eb71243f)
The package is a new version of the previously removed libhmac. The key parts, a malicious payload to inject into hijacked browser extensions, is not included in the package. The code allows hijacking browser extensions to - based on previous package - exfiltrate credentials. This package also contains code to create hidden SSH access to the machine with hardcoded credentials.


---

Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.


Campaign: 2026-05-libhmac


Reasons (based on the campaign):


 - crypto-related


 - exfiltration-credentials


 - exfiltration-crypto


 - exfiltration-browser-data

---

Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/hmacsync/MAL-2026-4828.json))

**References:**
- https://bad-packages.kam193.eu/pypi/package/hmacsync
- https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/hmacsync/MAL-2026-4828.json
- https://github.com/advisories/GHSA-93x2-rq2m-926g

Compromised versions (1)

= 1.0.0

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.