Executive Summary

CVE-2025-9577 is a security flaw in the TOTOLINK X2000R router (firmware up to version 2.0.0) where the root user account uses a weak default password ('123456') stored in a world-readable file (/etc/shadow.sample). The password is hashed with MD5-crypt, which can be cracked easily using tools like John the Ripper. This allows an attacker with local access to gain unauthorized root access to the device through the administrative interface or network services. [1, 2]

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Impact Analysis

This vulnerability can lead to unauthorized root access to the affected TOTOLINK router, compromising the device's confidentiality and security. An attacker with local access can exploit the weak default credentials to control the device, potentially leading to further network compromise or misuse of the router's administrative functions. However, exploitation is difficult and requires local access. [1, 2]

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Detection Guidance

This vulnerability can be detected by checking the presence and permissions of the file /etc/shadow.sample on the TOTOLINK X2000R device and verifying if it contains the default root password hash. Since the password is hashed using MD5-crypt and is weak (e.g., '123456'), tools like John the Ripper can be used to crack the password hash. Commands to detect this could include: 1) Access the device locally and run 'ls -l /etc/shadow.sample' to check file existence and permissions. 2) Extract the hash from /etc/shadow.sample and use John the Ripper to attempt cracking it, e.g., 'john --format=md5crypt shadow.sample'. Detection requires local access to the device. [1]

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Mitigation Strategies

Immediate mitigation steps include restricting local access to the device to prevent exploitation, as the attack requires local access and is difficult to perform. Since no known countermeasures or patches are available, it is recommended to replace the affected product or component to avoid risk. Additionally, changing default credentials if possible and ensuring sensitive files like /etc/shadow.sample are not world-readable can help reduce exposure. [2]

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