CVE-2023-20198

Cisco IOS XE Web UI: Privilege Escalation

As of , CVE-2023-20198 in Cisco IOS XE Web UI is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.

Exploited
Yes: CISA listed it on 16 October 2023
US federal deadline
20 October 20234 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.99Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
EPSS when listed
No score that dayThe EPSS file of the day CISA listed it has no score for it.
Public exploit
3 Metasploit modules
Fix
Vendor advice: www.cisco.comLinks below, from CISA's entry.

What CISA says to do

Verify that instances of Cisco IOS XE Web UI are in compliance with BOD 23-02 and apply mitigations per vendor instructions. For affected products (Cisco IOS XE Web UI exposed to the internet or to untrusted networks), follow vendor instructions to determine if a system may have been compromised and immediately report positive findings to CISA.

CISA's required action

What the flaw is

Cisco IOS XE Web UI contains a privilege escalation vulnerability in the web user interface that could allow a remote, unauthenticated attacker to create an account with privilege level 15 access. The attacker can then use that account to gain control of the affected device.

CISA's 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.

The CVE record's description, from cisco

CVE published
16 October 2023
Assigned by
cisco
CVSS
10.0 Critical (CVSS 3.1, from the CNA)
CWE-420
Unprotected Alternate Channel
CISA SSVC, exploitation
active
CISA SSVC, automatable
yes
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

Public exploits

Facts from Metasploit's module list and Exploit-DB's index; we never copy exploit code.

  • Metasploit: Cisco IOX XE Unauthenticated RCE Chainexploit module, rank excellent
  • Metasploit: Cisco IOX XE unauthenticated Command Line Interface (CLI) executionauxiliary module, rank normal
  • Metasploit: Cisco IOX XE unauthenticated OS command executionauxiliary module, rank normal

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