Anthropic plugin breach puts 5.000 computers at risk

# anthropic# claude# cursor# vscode

Hacks.gr

An official Claude extension distributed via Cursor's marketplace was backdoored for 12 hours, impacting up to 5,000 developers via malicious version 2.1.3

An official Claude extension distributed via Cursor's marketplace was backdoored for 12 hours, impacting up to 5,000 developers via malicious version 2.1.313 before version 2.1.314 was released.

Researchers confirmed the supply-chain incident, while Anthropic has not yet issued customer warnings or explained the account compromise.

The suspicious version appeared on the Cursor platform, which offers developer tools. According to Cursor, the problematic version 2.1.313 was distributed through the official Anthropic account. Anthropic released a new, fixed version a few hours later, as users' devices had probably automatically downloaded the dangerous update.

How the attack worked

According to Cursor, this version attempted to create a hidden access to the computer using the attackers' digital keys. At the same time, it activated the local login service and opened a communication channel to the outside, so that strangers could manage the device remotely. The code was designed to run on computers running Windows, macOS, and Linux.

Because add-ons in this environment run with the permissions of the main program that developers use, the dangerous version could potentially gain access to local files, source code, and other development tools.

What do we know so far?

Independent researchers confirmed that the problem was spread through the official Anthropic account. However, neither Cursor nor Anthropic have yet explained how the attackers gained control of the account. Anthropic has not issued a public warning to its customers about the incident.

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