The US Cybersecurity and Infrastructure Security Agency (CISA) warns that a recently patched critical vulnerability affecting some of the network-attached storage (NAS) products made by Zyxel has been exploited in attacks.
The Taiwanese device manufacturer published an advisory last week to warn customers that its NAS326, NAS540 and NAS542 devices, specifically ones running firmware version 5.21 and earlier, are impacted by a critical vulnerability.
The flaw, tracked as CVE-2023-27992, can be exploited for arbitrary command injection without authentication.
“The pre-authentication command injection vulnerability in some Zyxel NAS devices could allow an unauthenticated attacker to execute some operating system (OS) commands remotely by sending a crafted HTTP request,” the vendor said in the advisory published on June 20.
Zyxel has released patches for the impacted products and has urged customers to install them as soon as possible.
CISA updated its Known Exploited Vulnerabilities Catalog on Friday, June 23, to inform users that CVE-2023-27992 has been exploited in attacks. CISA has instructed federal agencies to take action by July 14.
There do not appear to be any public details on the attacks exploiting the Zyxel NAS product vulnerability, but it’s not uncommon for CISA to be the first to issue a warning over the exploitation of a flaw.
Zyxel device vulnerabilities can be exploited by botnets, such as variants of the Mirai DDoS botnet. The vendor has been known to issue alerts, urging customers to install patches for actively exploited security bugs.