CVE-2022-29058: Fortinet FortiAP RCE Vulnerability

CVE-2022-29058 Overview

CVE-2022-29058 is a command injection vulnerability affecting multiple Fortinet FortiAP wireless access point products. The vulnerability exists in the command line interpreter (CLI) of affected devices, where improper neutralization of special elements allows an authenticated attacker to execute unauthorized operating system commands through specifically crafted arguments passed to existing CLI commands.

Critical Impact

Authenticated attackers can achieve command injection on affected FortiAP devices, potentially leading to complete device compromise, data exfiltration, and lateral movement within the network infrastructure.

Affected Products

• Fortinet FortiAP 6.0.0 through 6.4.7, 7.0.0 through 7.0.3, and 7.2.0
• Fortinet FortiAP-S 6.0.0 through 6.4.7
• Fortinet FortiAP-W2 6.0.0 through 6.4.7, 7.0.0 through 7.0.3, and 7.2.0
• Fortinet FortiAP-U 5.4.0 through 6.2.3

Discovery Timeline

• September 6, 2022 - CVE-2022-29058 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-29058

Vulnerability Analysis

This vulnerability stems from insufficient input validation within the command line interpreter of FortiAP devices. When authenticated users interact with the CLI, certain commands accept user-supplied arguments that are not properly sanitized before being processed by the underlying operating system. This allows an attacker with valid credentials to inject malicious shell metacharacters or command sequences that execute with the privileges of the CLI process.

The vulnerability requires local access and authentication, meaning an attacker must first obtain valid credentials to the FortiAP device. However, once authenticated, the attacker can escalate their capabilities significantly by executing arbitrary OS commands. This could lead to complete compromise of the access point, including modification of device configurations, interception of wireless traffic, and pivoting to other network resources.

Root Cause

The root cause is improper neutralization of special elements used in OS commands (CWE-78) within the CLI argument parsing logic. The affected code fails to properly sanitize or escape shell metacharacters in user-supplied input before passing them to system command execution functions. This allows specially crafted input containing characters like semicolons, pipes, backticks, or command substitution sequences to break out of the intended command context and execute arbitrary commands.

Attack Vector

The attack requires local access to the device's command line interface. An authenticated attacker can exploit this vulnerability by:

1. Authenticating to the FortiAP device CLI with valid credentials
2. Identifying CLI commands that accept user-supplied arguments
3. Crafting malicious input containing OS command injection payloads
4. Executing the legitimate command with the malicious arguments
5. The injected commands execute with the privileges of the CLI process

The attack exploits the trust boundary between the CLI application and the underlying operating system, where user-controlled input is passed to shell command execution without adequate sanitization.

Detection Methods for CVE-2022-29058

Indicators of Compromise

• Unusual or unexpected command patterns in FortiAP CLI logs containing shell metacharacters
• Evidence of unauthorized configuration changes or system file modifications
• Anomalous network connections originating from FortiAP devices
• Unexpected processes running on FortiAP devices that deviate from normal operations

Detection Strategies

• Monitor FortiAP authentication logs for repeated login attempts or suspicious credential usage
• Implement logging for all CLI sessions and analyze for command injection patterns such as semicolons, pipes, backticks, or $() sequences
• Deploy network monitoring to detect unusual traffic patterns from wireless access points
• Configure SIEM rules to alert on command injection signatures in FortiAP log events

Monitoring Recommendations

• Enable comprehensive CLI command logging on all FortiAP devices
• Establish baseline behavior for FortiAP device activity and alert on deviations
• Monitor for unexpected outbound connections from access point management interfaces
• Review authentication logs regularly for unauthorized access attempts

How to Mitigate CVE-2022-29058

Immediate Actions Required

• Update all affected FortiAP, FortiAP-S, FortiAP-W2, and FortiAP-U devices to the latest firmware versions
• Audit and restrict CLI access to only essential administrative personnel
• Implement strong authentication mechanisms and consider multi-factor authentication for device management
• Review and limit network access to FortiAP management interfaces using ACLs or firewall rules

Patch Information

Fortinet has released security patches addressing this vulnerability. Administrators should consult the FortiGuard Security Advisory FG-IR-21-163 for detailed patch information and upgrade instructions. Upgrade paths vary by product line:

• FortiAP: Upgrade to versions above 7.0.3 or 7.2.0 as specified in the advisory
• FortiAP-S: Upgrade to versions above 6.4.7 as specified in the advisory
• FortiAP-W2: Upgrade to versions above 7.0.3 or 7.2.0 as specified in the advisory
• FortiAP-U: Upgrade to versions above 6.2.3 as specified in the advisory

Workarounds

• Restrict CLI access to trusted administrators only using role-based access controls
• Segment management network traffic to limit exposure of FortiAP administrative interfaces
• Monitor all CLI sessions in real-time for suspicious activity until patches can be applied
• Consider temporarily disabling CLI access if feasible and manage devices through alternative secure methods