Fake Postmark MCP npm package stole emails with one-liner

A fake npm package posing as Postmark's MCP (Model Context Protocol) server silently stole potentially thousands of emails a day by adding a single line of code that secretly copied outgoing messages to an attacker-controlled address. In a blog post late last week, Postmark warned users about "postmark-mcp" on npm impersonating the email delivery service and stealing its users' emails. "We want to be crystal clear: Postmark had absolutely nothing to do with this package or the malicious activity," the company said on September 25. "Here's what happened: A malicious actor created a fake package on npm impersonating our name, built trust over 15 versions, then added a backdoor in version 1.0.16 that secretly BCC'd emails to an external server." If you downloaded the fake package, Postmark recommends immediately removing it, checking email logs for suspicious activity, and rotating any credentials sent via email. While we don't know how many organizations were affected by this security incident, Postmark boasts "thousands" of customers, including Ikea, Asana, Minecraft, and 1Password, on its website. However, the company told The Register after publication that it knows of only one Postmark customer that actually used the affected package, and that its own systems were not breached and remain secure. Koi Security, which discovered the malicious package, says it was downloaded about 1,500 times in a week, integrated into hundreds of developer workflows, and likely stole thousands...