Overview
A critical security vulnerability, identified as CVE-2025-60688, affects ToToLink LR1200GB and NR1800X routers. This vulnerability is a stack buffer overflow located within the cstecgi.cgi binary, specifically in the setDefResponse function. Exploitation of this vulnerability could allow unauthenticated attackers to execute arbitrary code or cause memory corruption on the affected devices.
This article provides a detailed analysis of the vulnerability, its potential impact, and recommended mitigation steps.
Technical Details
The vulnerability arises from the use of the strcpy() function within the setDefResponse function of the cstecgi.cgi binary. The function processes the “IpAddress” parameter received from web requests. Crucially, strcpy() copies the value of “IpAddress” into a fixed-size stack buffer without performing any length validation. If the “IpAddress” parameter exceeds the buffer’s capacity, a stack buffer overflow occurs.
Affected Firmware Versions:
- ToToLink LR1200GB (V9.1.0u.6619_B20230130)
- ToToLink NR1800X (V9.1.0u.6681_B20230703)
The lack of authentication required to trigger the vulnerable code path significantly increases the severity of this issue.
CVSS Analysis
The vulnerability has been assigned a CVSS score of 6.5 (MEDIUM).
- CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- Attack Vector: Network (AV:N)
- Attack Complexity: Low (AC:L)
- Privileges Required: None (PR:N)
- User Interaction: None (UI:N)
- Scope: Unchanged (S:U)
- Confidentiality: None (C:N)
- Integrity: High (I:H)
- Availability: None (A:N)
While the confidentiality and availability are rated as None, the high integrity impact underscores the potential for attackers to modify the router’s configuration or inject malicious code, leading to serious security consequences.
Possible Impact
Successful exploitation of this vulnerability can lead to:
- Arbitrary Code Execution: An attacker could potentially execute arbitrary code on the router, gaining full control of the device.
- Memory Corruption: Overflowing the buffer can corrupt adjacent memory regions, potentially causing the router to crash or malfunction.
- Router Configuration Modification: An attacker could modify the router’s settings, such as DNS servers or firewall rules, redirecting traffic or creating backdoors.
- Botnet Recruitment: Compromised routers can be added to botnets, used for distributed denial-of-service (DDoS) attacks or other malicious activities.
Mitigation and Patch Steps
The recommended mitigation steps include:
- Upgrade Firmware: Check the ToToLink website for updated firmware that addresses this vulnerability. Apply the update immediately.
- Disable Remote Administration: If remote administration is not required, disable it to reduce the attack surface.
- Implement Network Segmentation: If possible, segment the network to limit the impact of a compromised router.
- Monitor Network Traffic: Monitor network traffic for suspicious activity that might indicate a compromised router.
Until a patch is available, consider implementing temporary workarounds, such as filtering incoming traffic to the router’s web interface.