CVE-2017-15656 in AsusWRT
Summary
by MITRE
Password are stored in plaintext in nvram in the HTTPd server in all current versions (<= 3.0.0.4.380.7743) of Asus asuswrt.
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Analysis
by VulDB Data Team • 02/03/2023
The vulnerability identified as CVE-2017-15656 represents a critical security flaw in the asuswrt firmware used by various ASUS router models. This issue affects all versions up to and including 3.0.0.4.380.7743, where passwords are persistently stored in plaintext format within the non-volatile random-access memory of the HTTPd server component. The flaw resides in the firmware's handling of authentication credentials, specifically within the web server implementation that manages user access to router administration interfaces. This represents a fundamental failure in credential storage practices that directly violates established security principles for protecting sensitive authentication data.
The technical implementation of this vulnerability stems from the improper handling of administrative passwords within the router's memory management system. When users configure administrative credentials for accessing the router's web interface, these passwords are not encrypted or hashed before being written to the non-volatile memory storage. This plaintext storage mechanism creates a persistent exposure point where any individual with access to the device's memory or the ability to perform certain system-level operations can directly extract these credentials. The vulnerability is particularly concerning because it affects the core HTTPd server functionality that serves as the primary interface for remote administration and configuration of the router's network settings.
The operational impact of this vulnerability extends far beyond simple credential exposure, creating multiple attack vectors and compromising the overall security posture of affected networks. An attacker who gains access to the router's memory can immediately obtain administrative passwords and subsequently gain complete control over the router's configuration, including network settings, firewall rules, DNS configurations, and other critical network parameters. This access enables man-in-the-middle attacks, traffic interception, network redirection, and potential lateral movement within the compromised network. The vulnerability aligns with CWE-312 (CWE-312: Cleartext Storage of Sensitive Information) and represents a direct violation of security best practices outlined in NIST SP 800-57 for protecting cryptographic keys and sensitive data. The exposure of administrative credentials effectively undermines the router's role as a security boundary within home and small office networks.
Mitigation strategies for this vulnerability require immediate firmware updates from ASUS to address the plaintext storage implementation. Organizations and individuals should prioritize updating their asuswrt firmware to versions that properly encrypt or hash administrative credentials before storage. System administrators should implement additional network security controls including network segmentation, intrusion detection systems, and regular security audits to monitor for unauthorized access attempts. The vulnerability demonstrates the critical importance of secure credential handling practices and highlights the need for proper security testing of embedded firmware components. From an ATT&CK framework perspective, this vulnerability maps to T1078 (Valid Accounts) and T1046 (Network Service Scanning) as attackers can leverage exposed credentials to establish persistent access and conduct reconnaissance activities. The incident underscores the necessity of implementing proper input validation and secure storage mechanisms for sensitive data in embedded systems, particularly those handling network administration functions.