Serious zero-day vulnerability in Cisco's IOS XE software: attackers can take control of routers and switches

Cisco has issued a critical security alert to administrators regarding a serious zero-day authentication bypass vulnerability in its IOS XE software. This flaw allows unauthenticated attackers to gain full administrator privileges and take complete control of routers and switches remotely.

Devices with the web UI enabled

This critical vulnerability has been officially identified with the code CVE-2023-20198 and is still awaiting a patch. It only affects devices that have the Web User Interface (Web UI) feature enabled, in combination with the HTTP or HTTPS Server feature enabled.

Attacks in progress and the ability to create accounts

Cisco has identified the active execution of this previously unknown vulnerability in the Web User Interface (Web UI) component of Cisco IOS XE Software. It is important to note that exploitation of the vulnerability is possible when such devices are exposed to the Internet or untrusted networks.

Cisco recommended mitigation measures

To mitigate this threat, Cisco recommends that administrators disable the HTTP server feature on systems exposed to the Internet, effectively eliminating the attack vector and blocking potential attacks. The company recommends customers to use commands like no ip http server or no ip http secure-server in global configuration mode to completely disable the HTTP server feature. Additionally, after disabling this feature, the copy running-configuration startup-configuration command should be run to ensure that the HTTP server feature is not unexpectedly enabled during system reboots.