Overview
CVE-2025-60695 is a medium-severity stack-based buffer overflow vulnerability discovered in the mtk_dut binary of Linksys E7350 routers running firmware version 1.1.00.032. This vulnerability allows local attackers to potentially cause a denial of service, memory corruption, or even achieve arbitrary code execution by exploiting a flaw in how the router handles network interface addresses.
Technical Details
The vulnerability lies within the sub_4045A8 function of the mtk_dut binary. This function reads the MAC address of a network interface from the /sys/class/net/%s/address file, where %s represents the network interface name (e.g., eth0, wlan0). The function reads up to 256 bytes of data from this file into a local buffer. Critically, it then copies this data into a caller-provided buffer (a1) using strcpy without any boundary checks. This lack of bounds checking allows an attacker, who has local access and can control the contents of /sys/class/net/%s/address, to write data beyond the allocated size of buffer a1.
The size of a1 is often significantly smaller than the 256 bytes read, commonly allocated between 20 and 32 bytes. By crafting a specially designed string larger than the allocated buffer and placing it in the /sys/class/net/%s/address file, an attacker can trigger a stack-based buffer overflow.
// Vulnerable Code Snippet (Conceptual)
char local_buffer[256];
char a1[32]; // Typically smaller than 256
// Reads from /sys/class/net/%s/address into local_buffer
// ...
strcpy(a1, local_buffer); // No bounds checking!
CVSS Analysis
The Common Vulnerability Scoring System (CVSS) assigns CVE-2025-60695 a score of 5.9, indicating a MEDIUM severity. The CVSS vector reflects the characteristics of the vulnerability:
- CVSS Score: 5.9
- Vector: (Details would depend on specific CVSS vector calculation, but generally involves local access, potential for code execution/DoS, etc.)
Possible Impact
Successful exploitation of this vulnerability can lead to several adverse effects:
- Memory Corruption: Overflowing the buffer overwrites adjacent memory locations on the stack, potentially corrupting critical data or program state.
- Denial of Service (DoS): Overwriting return addresses can cause the program to crash, resulting in a denial of service.
- Arbitrary Code Execution: With careful crafting of the overflowed data, an attacker may be able to overwrite the return address with the address of malicious code, leading to arbitrary code execution. This allows the attacker to gain complete control of the router.
Mitigation or Patch Steps
The primary mitigation strategy is to update the Linksys E7350 router to a firmware version that addresses this vulnerability. Check the Linksys support website for the latest firmware updates. As of this writing, it’s crucial to verify if a patch has been released. If no patch is available, consider the following temporary mitigations (though they may not be fully effective):
- Disable Remote Administration: Limit access to the router’s administrative interface to only local network connections.
- Monitor Router Activity: Keep an eye on the router’s logs for any suspicious activity.
Important: Applying the official patch released by Linksys is the most effective way to address this vulnerability. Continuously monitor the Linksys website for updates.
