A serious vulnerability labeled as CVE-2022-20665 has been discovered in the Command Line Interface (CLI) of Cisco StarOS, which could potentially allow an authenticated attacker to escalate privileges on an affected device. This issue stems from insufficient input validation of CLI commands and could be exploited by attackers who can send crafted commands to the CLI.

In this article, we will thoroughly examine this vulnerability and provide an in-depth explanation of the exploit details, including a code snippet of the vulnerability, links to original references, and some steps that administrators can take to mitigate this threat.

The Vulnerability

Cisco StarOS is a powerful operating system that runs on the ASR 500 series routers, which are widely used in service provider networks and other critical environments. The CLI in Cisco StarOS is a powerful management tool for configuring and managing the system.

The vulnerability (CVE-2022-20665) lies in the processing of CLI commands, where input validation is not correctly implemented. As a result, an attacker who is authenticated and has administrative access to the device can exploit this weak point to achieve root user privileges. By doing so, they can execute arbitrary code and potentially gain full control of the affected system.

Exploit Details

To exploit this vulnerability, an attacker must first possess valid administrative credentials for the device. Once authenticated, the attacker can send specially crafted commands to the CLI. These malformed commands bypass the input validation mechanism and allow the execution of arbitrary code with the privileges of the root user.

Here is a simple example of a malicious command that could be used to exploit this vulnerability

$ some-harmless-command | $(some-malicious-code)

While this is just a representation, the actual crafted command(s) would depend on the specific implementation and capabilities of the affected device.

Original References

Cisco has acknowledged this vulnerability and published an official security advisory that provides further details on the issue, affected products, and possible mitigation steps. The full advisory can be found here:

- Cisco Security Advisory

Cisco has assigned this vulnerability a high CVSS score of 7.2, indicating that it poses a significant risk to affected systems.

Mitigation Steps and Recommendations

Administrators of Cisco StarOS devices should take the following steps to mitigate this vulnerability:

Apply the appropriate software updates and security patches provided by Cisco.

3. Restrict administrative access to the CLI of the device, allowing only trusted and necessary users to access it.

Regularly monitor and audit CLI activities, keeping a close eye on suspicious commands and patterns.

In addition to these steps, it's essential to adopt a proactive security posture and keep security policies and software up to date to minimize the attack surface and protect against threats like these.

Conclusion

CVE-2022-20665 represents a significant security risk for administrators managing Cisco StarOS devices. By thoroughly understanding this vulnerability and taking appropriate steps to mitigate this threat, organizations can better safeguard their systems and prevent unauthorized access and privilege escalation. Be sure to monitor Cisco's security advisories and apply necessary patches and updates to keep your devices secure.

Timeline

Published on: 04/06/2022 19:15:00 UTC
Last modified on: 04/14/2022 15:45:00 UTC