CVE-2017-14698 in DSL-AC51
Summary
by MITRE
ASUS DSL-AC51, DSL-AC52U, DSL-AC55U, DSL-N55U C1, DSL-N55U D1, DSL-AC56U, DSL-N10_C1, DSL-N12U C1, DSL-N12E C1, DSL-N14U, DSL-N14U-B1, DSL-N16, DSL-N16U, DSL-N17U, DSL-N66U, and DSL-AC750 routers allow remote attackers to change passwords of arbitrary users via the http_passwd parameter to mod_login.asp.
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Analysis
by VulDB Data Team • 12/31/2019
This vulnerability exists in multiple ASUS router models including DSL-AC51, DSL-AC52U, DSL-AC55U, DSL-N55U C1, DSL-N55U D1, DSL-AC56U, DSL-N10_C1, DSL-N12U C1, DSL-N12E C1, DSL-N14U, DSL-N14U-B1, DSL-N16, DSL-N16U, DSL-N17U, DSL-N66U, and DSL-AC750 devices. The flaw resides in the web-based management interface where the mod_login.asp page fails to properly validate user input for the http_passwd parameter. This parameter is used to handle password changes within the router's administrative interface. The vulnerability represents a classic authorization bypass issue that allows unauthenticated remote attackers to manipulate user account credentials across the affected router models.
The technical implementation of this vulnerability stems from insufficient input validation and authentication checks within the router's web server component. When an attacker sends a specially crafted HTTP request containing the http_passwd parameter to the mod_login.asp endpoint, the router processes the request without verifying whether the requester has legitimate authorization to modify the target user's password. This weakness enables attackers to change passwords for any user account on the router, potentially gaining persistent access to the device's administrative interface. The vulnerability affects the authentication mechanism by allowing arbitrary password modification through a parameter that should require proper authentication and authorization.
The operational impact of this vulnerability is significant as it provides remote attackers with the ability to completely compromise router administrative access without requiring any prior authentication credentials. Once an attacker successfully exploits this vulnerability, they can gain full control over the affected router's configuration, including network settings, firewall rules, DNS configurations, and potentially access to connected devices on the local network. The risk is compounded by the fact that these routers are commonly deployed in residential and small office environments where network security may be less sophisticated. The vulnerability allows attackers to establish persistent backdoors, redirect traffic, or launch further attacks against connected devices, making it particularly dangerous in environments where these routers serve as primary network gateways.
The vulnerability maps to CWE-287 which addresses improper authentication issues in software systems. It also aligns with ATT&CK technique T1078 which covers legitimate credentials usage and privilege escalation. Organizations should immediately implement network segmentation to isolate affected devices from critical systems and apply firmware updates from ASUS as soon as they become available. Network monitoring should be enhanced to detect unusual authentication patterns and parameter manipulation attempts. Additionally, administrators should change default passwords on all router interfaces and disable unnecessary remote management features. The vulnerability demonstrates the importance of proper input validation and authentication checks in web-based management interfaces, particularly in embedded systems where security updates may be delayed or unavailable for older device models.