A recent attack on the npm ecosystem targeted developers through a malicious package named postmark-mcp, posing as the legitimate Postmark library. Over 15 releases, this package gained trust by mimicking Postmark’s naming and versioning, ultimately embedding a backdoor in version 1.0.16. This backdoor, introduced via a simple JavaScript line, BCC’d every outgoing email to an external attacker-controlled address, leading to the exfiltration of thousands of emails unnoticed. Postmark has confirmed it was not involved with this malicious package, and its official API remains secure.
To mitigate risks, users should uninstall postmark-mcp immediately, audit email logs for suspicious activity, and rotate credentials. Additionally, leveraging tools like npm audit can help detect impersonators. This incident emphasizes the importance of supply chain security; always verify package integrity and use official SDKs to prevent such sophisticated attacks. For more security insights, subscribe to the Postmark status page. Follow us on Google News and LinkedIn for updates.
