CVE-2023-20198
Description
Cisco is providing an update for the ongoing investigation into observed exploitation of the web UI feature in Cisco IOS XE Software. We are updating the list of fixed releases and adding the Software Checker. Our investigation has determined that the actors exploited two previously unknown issues. The attacker first exploited CVE-2023-20198 to gain initial access and issued a privilege 15 command to create a local user and password combination. This allowed the user to log in with normal user access. The attacker then exploited another component of the web UI feature, leveraging the new local user to elevate privilege to root and write the implant to the file system. Cisco has assigned CVE-2023-20273 to this issue. CVE-2023-20198 has been assigned a CVSS Score of 10.0. CVE-2023-20273 has been assigned a CVSS Score of 7.2. Both of these CVEs are being tracked by CSCwh87343.
Summary dbcve.org
CVE-2023-20198 is a critical vulnerability in Cisco IOS XE Software's web UI feature that allows unauthenticated attackers to gain initial access and create a local privilege 15 user. This is chained with CVE-2023-20273 (CVSS 7.2) to escalate to root and write a malicious implant to the file system. Both vulnerabilities are actively exploited in the wild.
Mitigation
Apply Cisco's fixed IOS XE releases; if patching is not immediately feasible, disable the web UI feature (http/https server) on affected devices and hunt for indicators of compromise.