Description

Cisco has issued a warning regarding a newly discovered zero-day vulnerability in its IOS XE software, which has been actively exploited by an unidentified threat actor to deploy a malicious Lua-based implant on vulnerable devices. This security flaw, known as CVE-2023-20273, pertains to a privilege escalation issue within the web user interface (UI) feature. It was used in conjunction with CVE-2023-20198 as part of an exploit chain. The attacker's initial step was to exploit CVE-2023-20198 to gain initial access, where they issued a privilege 15 command to create a local user and password combination. This allowed the attacker to log in with regular user privileges. Subsequently, the attacker leveraged another aspect of the web UI feature, using the newly created local user to escalate their privileges to root and write the implant to the file system, which is identified as CVE-2023-20273. Cisco has confirmed that a fix covering both vulnerabilities will be available to customers from October 22, 2023. In the meantime, it is recommended to disable the HTTP server feature. Although Cisco had previously mentioned an exploited security flaw in the same software, it is no longer associated with the recent zero-day discovery. The U.S. Cybersecurity and Infrastructure Security Agency has highlighted that an unauthenticated remote actor can exploit these vulnerabilities to take control of affected systems. These vulnerabilities enable the actor to create a privileged account, granting complete control over the compromised device. Successful exploitation of these vulnerabilities could allow attackers to gain unrestricted remote access to routers and switches, monitor network traffic, inject and redirect network traffic, and establish a persistent foothold within the network, as there are currently no protection solutions available for these devices.