CVE-2025-52046: Totolink A3300r Firmware RCE Vulnerability

CVE-2025-52046 Overview

CVE-2025-52046 is a critical command injection vulnerability discovered in the Totolink A3300R router firmware version 17.0.0cu.596_B20250515. The vulnerability exists in the sub_4197C0 function where the mac and desc parameters are improperly sanitized, allowing unauthenticated remote attackers to inject and execute arbitrary system commands through specially crafted HTTP requests.

This vulnerability is particularly severe because it requires no authentication, enabling any attacker with network access to the device's management interface to achieve full system compromise. Router vulnerabilities of this nature are frequently targeted by botnet operators and threat actors seeking to establish persistent network footholds.

Critical Impact

Unauthenticated remote attackers can execute arbitrary commands on affected Totolink A3300R routers, potentially leading to complete device takeover, network infiltration, credential theft, and use of compromised devices in botnet operations.

Affected Products

• Totolink A3300R Firmware version 17.0.0cu.596_B20250515
• Totolink A3300R hardware devices running the vulnerable firmware

Discovery Timeline

• 2025-07-17 - CVE-2025-52046 published to NVD
• 2025-09-26 - Last updated in NVD database

Technical Details for CVE-2025-52046

Vulnerability Analysis

The command injection vulnerability resides within the sub_4197C0 function of the Totolink A3300R firmware, which is associated with WiFi ACL (Access Control List) rules functionality. The vulnerable function processes user-supplied input from the mac and desc parameters without adequate sanitization or input validation before passing them to system command execution routines.

Command injection vulnerabilities (CWE-77) occur when an application constructs system commands using untrusted input without proper neutralization of special characters. In this case, an attacker can inject shell metacharacters and command sequences within the mac or desc parameters, causing the router to execute attacker-controlled commands with the privileges of the web server process—typically root on embedded devices.

The network-accessible nature of this vulnerability combined with the lack of authentication requirements creates an extremely dangerous attack surface. Attackers can exploit this vulnerability remotely without any prior access or credentials.

Root Cause

The root cause of this vulnerability is improper input validation in the sub_4197C0 function. The function accepts the mac and desc parameters from HTTP requests related to WiFi ACL rule configuration and directly incorporates these values into system command construction without sanitizing shell metacharacters such as semicolons (;), pipes (|), backticks (`), or command substitution sequences ($()).

This represents a failure to implement secure coding practices for handling untrusted input in system command contexts. The firmware developers did not implement input validation, output encoding, or parameterized command execution to prevent injection attacks.

Attack Vector

The attack vector for CVE-2025-52046 is network-based, requiring the attacker to have access to the router's web management interface. The exploitation process involves:

1. Target Identification: Attacker identifies a Totolink A3300R router running the vulnerable firmware version on the network
2. Request Crafting: Attacker constructs an HTTP request to the WiFi ACL rules endpoint with malicious payloads in the mac or desc parameters
3. Payload Injection: The malicious request contains shell command sequences embedded within the parameter values
4. Command Execution: The vulnerable sub_4197C0 function processes the request and executes the injected commands with system privileges

The vulnerability does not require authentication, meaning any attacker with network visibility to the router's management interface can exploit it. This includes attackers on the local network or, if the management interface is exposed to the internet, remote attackers anywhere on the internet.

For technical details on the exploitation methodology, refer to the GitHub CVE-2025-52046 Details and the Notion WiFi ACL Rules Guide.

Detection Methods for CVE-2025-52046

Indicators of Compromise

• Unusual outbound network connections from the router to unknown external IP addresses
• Unexpected processes running on the router that are not part of normal firmware operation
• Modified system configuration files or new user accounts on the device
• Presence of downloaded malware binaries or scripts in writable directories
• Router performance degradation or unexpected reboots indicating malicious activity

Detection Strategies

• Monitor HTTP access logs for requests to WiFi ACL configuration endpoints containing suspicious characters in mac or desc parameters (semicolons, pipes, backticks, $() sequences)
• Deploy network intrusion detection systems (IDS) with signatures for command injection patterns targeting Totolink devices
• Implement anomaly detection for unusual traffic patterns originating from router management interfaces
• Review web server logs for repeated or automated requests to the vulnerable endpoint

Monitoring Recommendations

• Enable logging on the router management interface if available and forward logs to a centralized SIEM
• Monitor network traffic for connections to known botnet command and control infrastructure
• Set up alerts for any changes to router configuration that are not initiated through authorized channels
• Regularly audit the firmware version running on network devices to identify vulnerable installations

How to Mitigate CVE-2025-52046

Immediate Actions Required

• Check if your Totolink A3300R router is running firmware version 17.0.0cu.596_B20250515 and prioritize remediation
• Restrict access to the router's web management interface to trusted internal networks only
• Disable remote management features if enabled and not strictly required
• Implement firewall rules to block unauthorized access to the router's administrative ports
• Consider network segmentation to isolate vulnerable devices from critical systems

Patch Information

At the time of publication, no vendor-supplied patch has been confirmed for CVE-2025-52046. Organizations should monitor the official Totolink support channels for firmware updates addressing this vulnerability. Contact Totolink support directly for guidance on available security updates.

Until a patch is available, implement the workarounds and compensating controls described below to reduce risk.

Workarounds

• Disable the web management interface entirely if remote administration is not required
• Configure access control lists on upstream network devices to restrict which IP addresses can reach the router's management interface
• Deploy a web application firewall (WAF) in front of the management interface to filter requests containing command injection patterns
• Consider replacing vulnerable devices with alternative hardware that has active security support

# Example: Restrict management interface access via upstream firewall
# Block external access to router management port (adjust IP and port as needed)
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP

# Allow management access only from specific admin workstation
iptables -I FORWARD -s 192.168.1.100 -d 192.168.1.1 -p tcp --dport 80 -j ACCEPT