CVE-2022-35491 in A3002RU
Summary
by MITRE • 08/11/2022
TOTOLINK A3002RU V3.0.0-B20220304.1804 has a hardcoded password for root in /etc/shadow.sample.
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Analysis
by VulDB Data Team • 09/04/2022
The vulnerability identified as CVE-2022-35491 represents a critical security flaw in the TOTOLINK A3002RU router firmware version V3.0.0-B20220304.1804. This issue stems from the presence of a hardcoded root password within the /etc/shadow.sample configuration file, which exposes the device to unauthorized administrative access. The flaw directly violates fundamental security principles by embedding credentials that should remain dynamic and unpredictable, creating an immediate and severe risk for network security. This type of vulnerability is categorized under CWE-798, which specifically addresses the use of hard-coded credentials in software systems.
The technical implementation of this vulnerability involves the router firmware containing a pre-configured administrative account with a known password that remains unchanged across all affected devices. When security researchers or malicious actors discover this hardcoded credential, they can immediately gain root access to the device without requiring additional authentication attempts or exploitation techniques. The presence of this credential in a sample configuration file suggests poor security practices during the development and testing phases, where developers may have left debugging credentials in production code. This flaw significantly reduces the attack surface required to compromise the device, as traditional password guessing or brute force attacks become unnecessary.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass complete network compromise. Once an attacker gains root access through the hardcoded password, they can modify router configurations, install malicious firmware, redirect network traffic, or establish persistent backdoors for future access. The compromised device becomes a potential launching point for lateral movement within the network, allowing attackers to target other connected devices or escalate privileges to gain control over additional systems. This vulnerability affects the confidentiality, integrity, and availability of the network infrastructure, potentially enabling data exfiltration, man-in-the-middle attacks, or disruption of network services. According to ATT&CK framework category T1078, this represents a legitimate credential use technique that allows adversaries to maintain persistent access to target systems.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. The most direct solution involves updating the router firmware to a version that removes or randomizes the hardcoded credentials, ensuring that all affected devices receive security patches from the vendor. Network administrators should also implement network segmentation and access controls to limit the potential impact of compromised devices. Additional protective measures include disabling unnecessary services, monitoring for unauthorized access attempts, and conducting regular security assessments of network infrastructure. The vulnerability highlights the importance of following secure development practices and conducting thorough security testing before releasing firmware updates to prevent similar issues in future deployments. Organizations should also establish procedures for tracking and managing firmware versions across their network assets to ensure timely patch deployment and maintain overall security posture.