x509-escapingnpm
Advisory published Updated
x509-escaping is a confirmed malicious npm package (MAL-2025-889) that steals credentials and exfiltrates sensitive data (malicious versions 0.0.0, 0.0.1, 0.0.2…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in x509-escaping (npm)
What this malware does
package.json declares preinstall: node index.js, so on npm install the shipped index.js runs automatically. It collects hostname, username, home directory, DNS servers, and current working directory, and reads /etc/passwd and /etc/hosts via fs.readFileSync, then POSTs the bundle over HTTPS to the hardcoded host agumuj6lhw9yqopq6npl1nlgu70yorcg.oastify.com (a Burp Collaborator out-of-band subdomain). The package name and single-purpose recon payload match the dependency-confusion reconnaissance pattern: no library functionality is shipped, only install-time data exfiltration to an attacker-controlled OOB host.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for x509-escaping (4 malicious versions).
If you installed it — respond
x509-escaping 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 x509-escaping 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
Campaign
References
Credits
- Amazon Inspector · finder
- ReversingLabs · finder
Detect & block this
O3 blocks x509-escaping-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.