CVE-2014-8243 in Linksys
Summary
by MITRE
Linksys SMART WiFi firmware on EA2700 and EA3500 devices; before 2.1.41 build 162351 on E4200v2 and EA4500 devices; before 1.1.41 build 162599 on EA6200 devices; before 1.1.40 build 160989 on EA6300, EA6400, EA6500, and EA6700 devices; and before 1.1.42 build 161129 on EA6900 devices allows remote attackers to obtain the administrator's MD5 password hash via a direct request for the /.htpasswd URI.
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Analysis
by VulDB Data Team • 10/19/2024
This vulnerability affects Linksys SMART WiFi firmware versions across multiple device models including EA2700, EA3500, E4200v2, EA4500, EA6200, EA6300, EA6400, EA6500, and EA6900 routers. The flaw resides in the web interface implementation where the system fails to properly authenticate access requests to the /.htpasswd URI endpoint. This represents a critical security weakness that violates the principle of least privilege and proper access control mechanisms. The vulnerability allows unauthenticated remote attackers to directly retrieve the administrator password hash without requiring any valid credentials or authentication tokens.
The technical implementation of this vulnerability stems from inadequate input validation and access control enforcement within the firmware's web server component. When a remote attacker sends a direct HTTP request to the /.htpasswd URI, the system responds with the MD5 hash of the administrator password stored in the configuration files. This occurs because the firmware does not properly verify whether the requesting entity has legitimate authorization to access sensitive administrative resources. The flaw demonstrates a classic path traversal and privilege escalation issue that aligns with CWE-285, which addresses improper authorization in software implementations. The vulnerability is particularly concerning as it provides attackers with immediate access to password hashes that can be subjected to offline dictionary attacks or rainbow table lookups.
From an operational impact perspective, this vulnerability fundamentally compromises the security posture of affected network devices by eliminating the need for authentication to obtain administrative credentials. Attackers can immediately escalate their privileges and gain complete control over the affected routers, enabling them to modify network configurations, redirect traffic, install malicious firmware, or establish persistent backdoors. The remote nature of the attack means that adversaries do not require physical access to the devices or network proximity, making the vulnerability particularly dangerous in enterprise and residential environments. This weakness directly violates security principles outlined in the NIST Cybersecurity Framework and aligns with ATT&CK technique T1566, which covers credential harvesting through social engineering and direct access methods.
The mitigation strategy requires immediate firmware updates to versions that properly implement access controls and authentication mechanisms for sensitive administrative endpoints. Network administrators should ensure that all affected devices are updated to the latest firmware releases provided by Linksys, specifically targeting versions 2.1.41 build 162351 for E4200v2 and EA4500 devices, 1.1.41 build 162599 for EA6200 devices, 1.1.40 build 160989 for EA6300, EA6400, EA6500, and EA6700 devices, and 1.1.42 build 161129 for EA6900 devices. Additionally, network segmentation should be implemented to isolate affected devices from critical network segments, and administrators should consider implementing additional security controls such as network access control lists and intrusion detection systems to monitor for suspicious access patterns. Organizations should also conduct thorough vulnerability assessments to identify any other potentially affected devices within their network infrastructure and ensure that default credentials are changed immediately upon device deployment.