Which versions of jsonist are malicious?

The following PyPI versions of jsonist are flagged malicious: 0.1.0. Treat any of these as compromised.

How do I remediate jsonist if I installed it?

jsonist 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.

I already installed jsonist — how do I know if it already compromised me?

If jsonist 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.

Is jsonist part of a known attack campaign?

Yes — jsonist is associated with the 2025-08-secmeasure campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find jsonist across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for jsonist (version 0.1.0).

Malicious package

jsonistPyPI

Advisory published Aug 14, 2025Updated Dec 3, 2025

jsonist is a confirmed malicious PyPI package (MAL-2025-191767) that steals credentials and exfiltrates sensitive data (malicious version 0.1.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in jsonist (PyPI)

MAL-2025-191767

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

pip uninstall jsonist

What this malware does

Calling a method starts downloading and starting an infostealer script

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

Campaign: 2025-08-secmeasure

Reasons (based on the campaign):

action-hidden-in-lib-usage
Downloads and executes a remote malicious script.
infostealer

Malicious versions

1 flagged

0.1.0

Indicators of compromise (SHA-256)

7f3396007d526f88250ad2b5c324ad8a550418f97213066b820b379ebd2cdbe6

4c74a199a696dbc18994242bc3c29e9a018ddda51fa2bbe224620d9ded6f1818

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for jsonist (version 0.1.0).
If you installed it — respond
jsonist 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 jsonist 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

No. jsonist on PyPI has been identified as a malicious package (version 0.1.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

2025-08-secmeasure

References

bad-packages.kam193.eu

Credits

Kamil Mańkowski (kam193)

Detect & block this

O3 blocks jsonist-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database