CVE-2022-20822: A Deep Dive into the Cisco ISE Vulnerability That Allows Unauthorized File Access by Attackers

A critical security vulnerability, CVE-2022-20822, has been discovered in the web-based management interface of Cisco Identity Services Engine (ISE). This vulnerability could enable an authenticated, remote attacker to read and delete files on the affected device without proper authorization. In this post, we will delve into the inner workings of this vulnerability, its potential impact on your network, and the current status of remediation efforts.

Code Snippet

To exploit this vulnerability, an attacker would typically send a crafted HTTP request containing specific character sequences to the affected system. Here's an example of a malicious HTTP request that could trigger the vulnerability:

GET /admin/API/download?filename=../../../../../../../../../etc/passwd HTTP/1.1
Host: vulnerable-ise.example.com
Authorization: Basic YWRtaW46cGFzc3dvcmQ=

This example request could potentially allow an attacker to read sensitive files, such as the /etc/passwd file on a Linux-based system, which should not be accessible by an attacker.

Original References

Cisco has published an official security advisory detailing this vulnerability, which you can find here: Cisco Security Advisory – CVE-2022-20822.

Further information about this vulnerability can also be found at the CVE website: CVE-2022-20822.

Exploit Details

The root cause of this vulnerability is insufficient validation of user-supplied input in the Cisco ISE web-based management interface. An authenticated attacker can craft an HTTP request containing specific character sequences, such as "../" to traverse directories on the affected system. By sending such requests, an attacker can read or delete files that their configured administrative level should not have access to.

The affected system must have an exposed web-based management interface.

Attackers who successfully exploit this vulnerability could gain unauthorized access to sensitive system files, which may contain valuable information, such as configuration files, passwords, or encryption keys. Moreover, attackers could delete crucial files, potentially causing system instability, service degradation, or outright failure.

Mitigation and Remediation

Cisco has acknowledged the severity of this vulnerability and plans to release software updates to address it. In the meantime, concerned administrators can implement the following best practices to minimize the potential impact of this vulnerability:

1. Limit access to the Cisco ISE web-based management interface to only trusted networks and VPN connections.
2. Regularly review and update user account privileges, ensuring that only necessary individuals have access to the administrative interface.
3. Monitor system log files for signs of intrusion, such as unauthorized access attempts or privilege escalations.

Conclusion

The CVE-2022-20822 vulnerability in the Cisco ISE web-based management interface presents a significant risk to the confidentiality and integrity of affected devices. By staying informed, implementing best practices, and applying the forthcoming patches from Cisco, network administrators can protect their networks against exploitation by attackers.

Timeline

Published on: 10/26/2022 15:15:00 UTC
Last modified on: 10/31/2022 17:40:00 UTC