CVE-2022-20822: Cisco ISE Path Traversal Vulnerability

CVE-2022-20822 Overview

A path traversal vulnerability exists in the web-based management interface of Cisco Identity Services Engine (ISE) that could allow an authenticated, remote attacker to read and delete files on an affected device. This vulnerability is due to insufficient validation of user-supplied input, enabling attackers to send crafted HTTP requests containing special character sequences to bypass access controls and manipulate files beyond their authorized administrative level.

Critical Impact

Authenticated attackers can read or delete sensitive files on vulnerable Cisco ISE devices, potentially accessing configuration data, credentials, or disrupting critical identity services infrastructure.

Affected Products

• Cisco Identity Services Engine 3.1 (Base)
• Cisco Identity Services Engine 3.1 Patch 1
• Cisco Identity Services Engine 3.1 Patch 3
• Cisco Identity Services Engine 3.2 (Base)

Discovery Timeline

• October 26, 2022 - CVE-2022-20822 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-20822

Vulnerability Analysis

This path traversal vulnerability (CWE-22) combined with improper input validation (CWE-20) affects the web-based management interface of Cisco Identity Services Engine. The flaw allows authenticated attackers to escape the intended directory structure and access files anywhere on the system that the web application has permissions to read or delete.

The vulnerability requires authenticated access to the ISE management interface, meaning an attacker must have valid credentials. However, once authenticated, even users with limited administrative privileges can potentially access files that should be restricted to higher privilege levels. This represents a significant authorization bypass that could expose sensitive configuration data, certificates, or other critical system files.

Root Cause

The root cause of CVE-2022-20822 stems from insufficient validation of user-supplied input in the web-based management interface. The application fails to properly sanitize HTTP request parameters that reference file paths, allowing directory traversal sequences (such as ../) to be processed. This improper input validation enables attackers to craft malicious requests that navigate outside the intended directory boundaries.

Attack Vector

The attack leverages network-accessible HTTP requests to the Cisco ISE web management interface. An attacker with valid authentication credentials can exploit this vulnerability by crafting HTTP requests containing special character sequences designed to traverse directory structures.

The exploitation requires:

1. Network access to the Cisco ISE management interface
2. Valid authentication credentials (even low-privilege accounts)
3. Crafted HTTP requests with path traversal sequences

A successful exploit allows the attacker to read sensitive files such as configuration files, certificates, or system data, and potentially delete critical files that could disrupt ISE operations. The attack does not require user interaction and can be executed remotely over the network.

For detailed technical analysis and proof-of-concept information, refer to the Yoroi CVE Advisory and the Cisco Security Advisory.

Detection Methods for CVE-2022-20822

Indicators of Compromise

• HTTP requests to ISE management interface containing path traversal sequences such as ../, ..%2f, or similar encoded variants
• Unusual file access patterns in ISE system logs indicating access to files outside normal web application directories
• Unexpected file deletions or modifications in ISE configuration directories
• Authentication events followed by suspicious file operations from the same session

Detection Strategies

• Monitor HTTP access logs for requests containing directory traversal patterns (e.g., .., %2e%2e, encoded path sequences)
• Implement web application firewall (WAF) rules to detect and block path traversal attempts
• Configure SIEM alerts for anomalous file system access patterns on ISE appliances
• Review ISE audit logs for file operations that deviate from expected administrative actions

Monitoring Recommendations

• Enable detailed logging on Cisco ISE management interface and forward logs to centralized SIEM
• Configure file integrity monitoring (FIM) on critical ISE configuration and system files
• Implement network detection rules for HTTP requests with path traversal indicators targeting ISE management ports
• Establish baseline behavior for administrative file access and alert on deviations

How to Mitigate CVE-2022-20822

Immediate Actions Required

• Review the Cisco Security Advisory for affected version details and patch availability
• Restrict network access to ISE management interface to trusted administrative networks only
• Audit user accounts with access to ISE management and remove unnecessary privileges
• Implement additional access controls such as VPN requirements or jump hosts for management access
• Monitor for exploitation attempts while awaiting patch deployment

Patch Information

Cisco has announced plans to release software updates that address this vulnerability. Organizations should monitor the Cisco Security Advisory for patch release announcements and apply updates as soon as they become available. Ensure all ISE deployments are upgraded to patched versions once released.

Workarounds

• Restrict management interface access to specific trusted IP addresses using access control lists (ACLs)
• Implement network segmentation to isolate ISE management interfaces from general network access
• Deploy a web application firewall (WAF) in front of the ISE management interface to filter malicious requests
• Enable multi-factor authentication (MFA) for all ISE administrative accounts to reduce credential compromise risk
• Consider implementing additional proxy-based access controls for the management interface

# Example ACL configuration to restrict ISE management access
# Apply on network infrastructure protecting ISE management interface
access-list ISE-MGMT-RESTRICT permit tcp 10.0.100.0 0.0.0.255 host 192.168.1.10 eq 443
access-list ISE-MGMT-RESTRICT deny tcp any host 192.168.1.10 eq 443
access-list ISE-MGMT-RESTRICT permit ip any any