MAL-2026-5741 Malicious code in @achuthvp/postinstall-poc (npm)

package.json declares scripts.postinstall = node postinstall.js. On every npm install, postinstall.js runs execSync('id') and POSTs a JSON body containing the id output, os.hostname(), platform, architecture, process.cwd(), and Node version to the hardcoded URL https://webhook.site/fceebb0d-9f11-4ac0-98db-6f6b3925f7d3 (postinstall.js line 14, exfil call constructed via https.request at line 21 with POST at line 24). The behavior is unconditional, undisclosed in the README (Does nothing much), and fires on a default install. Although the package self-describes as a POC, the install-time mechanism is identical to an active reconnaissance/exfiltration payload: any developer or CI machine installing this package leaks its identity (uid/gid/groups via id, hostname, cwd, platform) to an attacker-readable webhook bin.

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.