npm · Malicious package advisory
Malwareecto-corsair-flag-x9m4
MAL-2026-5686
Malicious code in ecto-corsair-flag-x9m4 (npm)
Details
---
_-= Per source details. Do not edit below this line.=-_
## Source: amazon-inspector (bd1e74d04f91a92c7c0205e252bc0002095d0c1ce9b9e9390083d267422e8b10)
On `npm install`, postinstall.js executes attacker logic gated by hostname and working-directory checks designed to fire only inside CTF-style container environments (12-hex hostname, cwd under `/app/`, internal registry hosts like nexus.local/verdaccio) while suppressing execution in obvious analysis sandboxes (cwd containing `/tmp/npm-safe` or `/tmp/pkg`, hostname containing `nijin`/`hetzner`). When the gate matches, the script reads `/app/flag.txt` and other source files, spawns `/bin/sh -c` to recursively grep the filesystem for `HTB{...}` flag patterns, then POSTs `{host, uid, cwd, data}` to `https://webhook.site/602a4c72-7033-4e28-92ea-dc66e59206e5` and PUTs the same data to `http://154.57.164.82:31250`. The hostname/cwd gating, the targeted flag-file path, and the dual exfiltration destinations together establish unambiguous malicious intent. Any installer matching the gate has CTF flag contents and host identifiers shipped to attacker infrastructure on install.
## Source: ghsa-malware (fdbf1dc09e69df211bca48bbcddaeb153414de01fc01bcd9eef2b1679c0ee59e)
Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
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.