Malware in PostHog NPM packages

I know many of us use a really excellent PostHog service, but it seems their latest version of `posthog-js` NPM package contains malware.

Reported to their security channel, also reported to NPM, but also wanted to raise awareness here.

Update: It seems all their NPM packages have the same problem

Update 2: https://status.posthog.com/

8 points | by roskoalexey 3 hours ago

7 comments

  • timgl 1 hour ago
    co-founder of PostHog here. It looks like we were also a victim of this attack: https://helixguard.ai/blog/malicious-sha1hulud-2025-11-24

    We've rotated keys and passwords, unpublished all affected packages and have pushed new versions, so make sure you're on the latest version of our SDKs.

    We're still figuring out how this key got compromised, and we'll follow up with a post-mortem. We'll update status.posthog.com with more updates as well.

  • roskoalexey 2 hours ago
    Some more details:

    1. Malware uses a "preinstall" NPM script, which is triggered upon you running `npm install`.

    2. Malware installs `bun`.

    3. Then it installs and starts `trufflehog` (a tool for scanning code for secrets, API keys, passwords, etc.).

  • sakce 2 hours ago
    Thank you for flagging this - we are actively working on it and will be back with an update!
  • kothariji 2 hours ago
    here is the report - https://helixguard.ai/blog/malicious-sha1hulud-2025-11-24
  • roskoalexey 3 hours ago
    Also:

    It seems many of their other NPM packages also have the same problem. https://www.npmjs.com/~timgl (all published 5 hours ago)

  • roskoalexey 3 hours ago
    Details:

    In `package.json`, it has a script `"preinstall": "node setup_bun.js"` + files `setup_bun.js` and `bun_environment.js` which are apparently is the malware.

  • rvz 3 hours ago
    This feels like an impending disaster about to be unraveled in lots of npm packages.

    Looking forward to the post-mortem.