CVE-2014-7858 in DNR-326
Summary
by MITRE
The check_login function in D-Link DNR-326 before 2.10 build 03 allows remote attackers to bypass authentication and log in by setting the username cookie parameter to an arbitrary string.
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Analysis
by VulDB Data Team • 12/16/2022
The vulnerability identified as CVE-2014-7858 affects the D-Link DNR-326 network device firmware versions prior to 2.10 build 03, representing a critical authentication bypass flaw that undermines the device's security posture. This issue resides within the check_login function implementation, where the system fails to properly validate the username parameter submitted through HTTP cookies. The vulnerability specifically targets the authentication mechanism by allowing remote attackers to manipulate the username cookie value to arbitrary strings without proper verification, effectively circumventing the intended access controls.
The technical exploitation of this vulnerability stems from a fundamental flaw in input validation and authentication logic within the DNR-326's web interface. When a user attempts to authenticate, the system should verify the provided credentials against a legitimate user database or predefined account settings. However, the check_login function in vulnerable versions fails to properly sanitize or validate the username parameter received via the HTTP cookie header, creating an opportunity for attackers to bypass authentication entirely. This represents a classic case of insufficient input validation where the system trusts user-provided data without adequate verification mechanisms. The vulnerability aligns with CWE-287, which addresses improper authentication issues, and more specifically with CWE-345, which deals with insufficient verification of data authenticity.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it provides attackers with complete administrative control over the affected D-Link DNR-326 device. Remote attackers can leverage this flaw to gain full access to network configuration settings, modify firewall rules, change network parameters, and potentially establish persistent backdoors within the network infrastructure. This authentication bypass enables attackers to perform actions such as disabling security features, redirecting network traffic, or even using the device as a pivot point for further attacks against internal network resources. The implications are particularly severe given that DNR-326 devices are typically deployed in enterprise and home network environments where they serve as critical components of network infrastructure, making them attractive targets for attackers seeking persistent access.
The attack surface for this vulnerability is particularly concerning as it requires no local access or physical presence, allowing attackers to exploit the flaw remotely over the network. The implementation of the fix involves proper input validation of the username cookie parameter, ensuring that any authentication attempt undergoes proper credential verification before granting access. Organizations should implement immediate mitigation strategies including firmware updates to version 2.10 build 03 or later, network segmentation to limit access to affected devices, and monitoring for suspicious authentication attempts. Security professionals should also consider implementing network-based intrusion detection systems that can identify anomalous cookie values or authentication patterns that may indicate exploitation attempts. This vulnerability demonstrates the critical importance of robust authentication mechanisms and proper input validation in network devices, aligning with ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting through network attacks.