Cisco REST API Container for IOS XE Software Authentication Bypass Vulnerability

Successful exploitation of CVE-2019-12643 allows an attacker to bypass authentication and obtain the token-id of an authenticated user. This token-id can then be leveraged to execute privileged commands and gain complete control over the affected Cisco IOS XE device. The potential impact is severe, encompassing data breaches, system compromise, and disruption of network services. This vulnerability shares similarities with other authentication bypass flaws where stolen or bypassed credentials grant attackers elevated privileges, potentially enabling lateral movement within the network.

Organizations heavily reliant on Cisco IOS XE devices for network management and automation are particularly at risk. Environments with weak authentication policies or inadequate network segmentation are also more vulnerable. Shared hosting environments utilizing Cisco IOS XE devices pose a significant risk due to the potential for cross-tenant exploitation.

• cisco: Use Cisco's security advisory to identify affected devices. • linux / server: Examine system logs (e.g., /var/log/syslog) for unusual HTTP requests to the REST API endpoints, particularly those originating from unauthorized sources. Use tcpdump or Wireshark to capture and analyze network traffic. • generic web: Monitor access logs for requests to /api/token or other authentication-related endpoints. Look for requests without proper authentication headers.

grep -i 'authentication failed' /var/log/syslog

1. 2019-08-28Disclosure

   disclosure

2. 2019-08-28Patch

   patch

1. Reserviert2019-06-04
2. Veröffentlicht2019-08-28
3. Geändert2024-11-19
4. EPSS aktualisiert2026-04-02

The primary mitigation for CVE-2019-12643 is to upgrade the Cisco REST API Container to version 16.09.03 or later. If immediate upgrade is not feasible, consider implementing network segmentation to limit the potential blast radius of a successful attack. Restrict access to the REST API endpoints to only authorized users and systems. Monitor REST API logs for suspicious activity, particularly failed authentication attempts and unusual request patterns. While a WAF cannot directly prevent this bypass, it can help detect and block malicious requests based on known attack patterns. After upgrade, confirm by verifying the version number of the REST API Container using the show version command on the Cisco IOS XE device.