Actively exploited Cisco 0-day with maximum 10 severity gives full network control

Enlarge / Cables run into a Cisco data switch. (credit: Getty Images)

Cisco is urging customers to protect their devices following the discovery of a critical, actively exploited zero-day vulnerability that’s giving threat actors full administrative control of networks.

“Successful exploitation of this vulnerability allows an attacker to create an account on the affected device with privilege level 15 access, effectively granting them full control of the compromised device and allowing possible subsequent unauthorized activity,” members of Cisco’s Talos security team wrote Monday. “This is a critical vulnerability, and we strongly recommend affected entities immediately implement the steps outlined in Cisco’s PSIRT advisory.”

Under exploitation for 4 weeks

The previously unknown vulnerability, which is tracked as CVE-2023-20198, carries the maximum severity rating of 10. It resides in the Web User Interface of Cisco IOS XE software when exposed to the Internet or untrusted networks. Any switch, router, or wireless LAN controller running IOS XE that has the HTTP or HTTPS Server feature enabled and exposed to the Internet is vulnerable. At the time this post went live, the Shodan search engine showed that as many as 80,000 Internet-connected devices could be affected.