Overview
Cisco IOS XE contains a command injection vulnerability in the web user interface. When chained with CVE-2023-20198, the attacker can leverage the new local user to elevate privilege to root and write the implant to the file system. Cisco identified CVE-2023-20273 as the vulnerability exploited to deploy the implant. CVE-2021-1435, previously associated with the exploitation events, is no longer believed to be related to this activity.
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-webui-privesc-j22SaA4z; https://nvd.nist.gov/vuln/detail/CVE-2023-20273
Key Details
| Property | Value |
|---|---|
| CVE ID | CVE-2023-20273 |
| Vendor / Product | Cisco — Cisco IOS XE Web UI |
| NVD Published | 2023-10-25 |
| NVD Last Modified | 2025-10-28 |
| CVSS 3.1 Score | 7.2 |
| CVSS 3.1 Vector | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
| Severity | HIGH |
| CWE | CWE-78 |
| CISA KEV Added | 2023-10-23 |
| CISA KEV Deadline | 2023-10-27 |
| Known Ransomware Use | No |
CVSS 3.1 Breakdown
Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Required Action
CISA BOD 22-01 Deadline: 2023-10-27.
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.
Timeline
| Date | Event |
|---|---|
| 2023-10-23 | Added to CISA Known Exploited Vulnerabilities catalog |
| 2023-10-27 | CISA BOD 22-01 remediation deadline |
References
| Resource | Type |
|---|---|
| NVD — CVE-2023-20273 | Vulnerability Database |
| CISA KEV Catalog Entry | US Government |