Fortra has released an emergency fix, version 7.1.2, to address a zero-day vulnerability in the GoAnywhere MFT secure file transfer protocol that has been actively exploited by hackers.

The zero-day bug resides in the administrative web interface and could be exploited by a remote attacker to achieve remote code execution via a malicious request. In most cases, the administrator console is not exposed to the internet and should only be accessible via a private internal network or by an allow-listed IP address.

“Due to the nature of the attack, it is critical to note that every managed credential within your GoAnywhere environment should be considered potentially compromised. This includes passwords and keys used to access any external systems with which GoAnywhere is integrated. Ensure that all credentials have been revoked from those external systems and review relevant access logs related to those systems. This also includes passwords and keys used to encrypt files within the system,” Fortra said in a security advisory (available only via a free account).

According to a Shodan search query, there are nearly 1,000 GoAnywhere instances exposed on the internet.

Earlier this week, a proof-of-concept (PoC) code was released that could be used to achieve remote code execution on Internet-exposed and unpatched GoAnywhere MFT servers.