CVE-2021-42886 in EX1200T
Summary
by MITRE • 06/03/2022
TOTOLINK EX1200T V4.1.2cu.5215 contains an information disclosure vulnerability where an attacker can get the apmib configuration file without authorization, and usernames and passwords can be found in the decoded file.
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Analysis
by VulDB Data Team • 06/08/2022
The CVE-2021-42886 vulnerability affects the TOTOLINK EX1200T router model running firmware version V4.1.2cu.5215, representing a critical information disclosure flaw that undermines the security posture of network infrastructure devices. This vulnerability stems from inadequate access controls within the device's web administration interface, allowing unauthenticated attackers to directly access sensitive configuration files through improper input validation mechanisms. The flaw specifically targets the apmib configuration file which contains critical system information including administrative credentials stored in plaintext format.
The technical implementation of this vulnerability resides in the router's web server component where it fails to properly authenticate requests for system configuration data. When an attacker accesses certain endpoints within the device's management interface, the system does not verify whether the requesting entity possesses proper authorization credentials. This misconfiguration creates an information exposure condition that aligns with CWE-200, which describes improper information disclosure vulnerabilities in software systems. The apmib file typically contains serialized configuration data including wireless network settings, user account credentials, and administrative access information that can be decoded by unauthorized parties without requiring any authentication.
From an operational perspective, this vulnerability presents significant risk to network security as it enables attackers to obtain administrative credentials without any authentication requirements. The disclosed credentials can be used to gain full administrative control over the router, allowing threat actors to modify network settings, redirect traffic, implement man-in-the-middle attacks, or establish persistent access points within the network. The impact extends beyond individual device compromise as compromised router credentials can be used to access other network resources that trust the router as a gateway or gateway device. This vulnerability particularly affects enterprise and home network environments where router security is often overlooked, creating potential attack vectors for lateral movement and extended network infiltration.
The vulnerability demonstrates a clear violation of security principles including the principle of least privilege and proper access control mechanisms. It represents a failure in implementing basic authentication checks for sensitive system files and aligns with ATT&CK technique T1566.002 for credential access through unauthorized access to system files. Network defenders should implement immediate mitigation measures including firmware updates from TOTOLINK, network segmentation to isolate affected devices, and monitoring for unauthorized access attempts. Additionally, organizations should conduct comprehensive network assessments to identify other potentially vulnerable devices and implement network access controls to prevent unauthorized access to administrative interfaces. The vulnerability underscores the critical importance of regular firmware updates and proper security configuration management in maintaining network infrastructure integrity.