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CVE-2023-20198: Cisco IOS XE Web UI Privilege Escalation Vulnerability

CVE-2023-20198 is rated critical with a CVSS v3.1 base score of 10.0 and affects Cisco IOS XE Web UI, along with 2 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-10-16, which means exploitation in the wild has been observed.

Vulnerability 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.

Severity breakdown

CVSS v3.1 10.0: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-420: Unprotected Alternate Channel

The product protects a primary channel, but it does not use the same level of protection for an alternate channel.

Affected products

  • Cisco IOS Xe: from 16.12 before 16.12.10a; from 17.3 before 17.3.8a; from 17.6 before 17.6.6a; from 17.9 before 17.9.4a
  • Rockwellautomation Allen Bradley Stratix 5200 Firmware: before 17.12.02
  • Rockwellautomation Allen Bradley Stratix 5800 Firmware: before 17.12.02

References