CVE-2022-23972: ASUS RT-AX56U Firmware SQLi Vulnerability

CVE-2022-23972 Overview

CVE-2022-23972 is an SQL injection vulnerability affecting the ASUS RT-AX56U wireless router. The vulnerability exists in the device's SQL handling function due to insufficient user input validation. An unauthenticated attacker with access to the local area network (LAN) can exploit this flaw to inject arbitrary SQL code, enabling them to read, modify, and delete database contents.

Critical Impact

Unauthenticated LAN attackers can exploit this SQL injection vulnerability to fully compromise the router's database, potentially leading to credential theft, configuration manipulation, and complete device takeover.

Affected Products

• ASUS RT-AX56U Firmware version 3.0.0.4.386.45898
• ASUS RT-AX56U hardware devices

Discovery Timeline

• 2022-04-07 - CVE-2022-23972 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-23972

Vulnerability Analysis

This vulnerability is classified as CWE-89 (Improper Neutralization of Special Elements used in an SQL Command), commonly known as SQL Injection. The ASUS RT-AX56U router contains an SQL handling function that fails to properly validate and sanitize user-supplied input before incorporating it into SQL queries.

The attack vector requires adjacent network access, meaning the attacker must be on the same local network segment as the vulnerable device. However, once network access is established, no authentication is required to exploit the vulnerability, significantly lowering the barrier for successful attacks.

Successful exploitation allows an attacker to:

• Read sensitive data: Extract stored credentials, configuration settings, and network information
• Modify database contents: Alter device configurations, user permissions, and access controls
• Delete database entries: Remove logs, user accounts, or critical configuration data

Root Cause

The root cause of CVE-2022-23972 is insufficient input validation in the router's SQL handling function. When user-supplied data is passed to SQL queries without proper sanitization or parameterized queries, special SQL characters and commands can be interpreted as part of the query structure rather than as literal data.

This is a classic SQL injection scenario where the application concatenates user input directly into SQL statements, allowing attackers to manipulate query logic by injecting SQL metacharacters such as single quotes, semicolons, and SQL keywords.

Attack Vector

The attack requires adjacent network positioning (LAN access). An attacker connected to the same network as the ASUS RT-AX56U router can send specially crafted requests containing malicious SQL payloads to the vulnerable SQL handling function.

Since no authentication is required to reach the vulnerable endpoint, any device on the local network—including compromised IoT devices, guest network clients, or malicious insiders—could potentially exploit this vulnerability.

The vulnerability manifests when malicious SQL statements are embedded within input fields or parameters that are processed by the router's SQL handling function. For detailed technical information, refer to the TWcert Security Advisory.

Detection Methods for CVE-2022-23972

Indicators of Compromise

• Unusual database query patterns or errors in router logs indicating SQL syntax anomalies
• Unexpected changes to router configuration, user accounts, or network settings
• Evidence of unauthorized access to router management interfaces from LAN devices
• Database integrity violations or missing configuration entries

Detection Strategies

• Monitor network traffic to the router's management interfaces for requests containing SQL injection patterns such as single quotes, UNION SELECT statements, or OR 1=1 constructs
• Implement intrusion detection rules to identify common SQL injection attack signatures targeting embedded device interfaces
• Enable and review router logging for authentication anomalies and configuration changes
• Deploy network segmentation monitoring to detect unauthorized lateral movement attempts

Monitoring Recommendations

• Regularly audit router configuration backups to detect unauthorized modifications
• Monitor for firmware integrity by comparing checksums against known-good versions
• Implement network access controls to restrict which devices can communicate with router management interfaces
• Review connected device lists for unknown or suspicious clients that may be staging attacks

How to Mitigate CVE-2022-23972

Immediate Actions Required

• Update the ASUS RT-AX56U firmware to the latest available version from ASUS support
• Restrict access to router management interfaces to trusted devices only
• Segment the network to limit exposure of the router's management functions
• Monitor for any signs of compromise and consider resetting the device to factory defaults if exploitation is suspected

Patch Information

ASUS has addressed this vulnerability in firmware updates released after version 3.0.0.4.386.45898. Administrators should visit the official ASUS support website to download and apply the latest firmware for the RT-AX56U router. Consult the TWcert Security Advisory for additional remediation guidance.

Workarounds

• Disable remote management features and restrict administrative access to wired connections only
• Implement MAC address filtering to limit which devices can access the router's management interface
• Configure firewall rules on the router to restrict management interface access to specific trusted IP addresses
• Isolate IoT and guest devices on separate network segments to reduce the attack surface from potentially compromised LAN clients

# Example: Restrict management interface access (router-specific syntax may vary)
# Access router configuration and navigate to Administration settings
# Disable WAN access to web interface
# Enable access restrictions to limit management to specific MAC addresses
# Consider enabling HTTPS-only access to management interface