CVE-2017-6549 in RT-AC53
Summary
by MITRE
Session hijack vulnerability in httpd in ASUS ASUSWRT on RT-AC53 3.0.0.4.380.6038 devices allows remote attackers to steal any active admin session by sending cgi_logout and asusrouter-Windows-IFTTT-1.0 in certain HTTP headers.
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Analysis
by VulDB Data Team • 08/18/2024
This vulnerability represents a critical session hijacking flaw in the ASUSWRT firmware version 3.0.0.4.380.6038 running on RT-AC53 routers. The issue stems from improper session management within the httpd web server component, allowing remote attackers to exploit a weakness in the authentication mechanism. Attackers can manipulate HTTP headers to hijack active administrator sessions without requiring valid credentials, effectively bypassing the authentication process entirely. The vulnerability specifically leverages the presence of certain header values including cgi_logout and asusrouter-Windows-IFTTT-1.0 to manipulate session state and gain unauthorized administrative access to the router's web interface.
The technical implementation of this vulnerability involves manipulating HTTP request headers to exploit a flaw in how the web server processes session identifiers and authentication tokens. When the httpd service receives requests with these specific header combinations, it fails to properly validate session integrity, allowing attackers to forge session cookies or manipulate existing session data. This weakness falls under the category of weak session management as defined by CWE-613, where insufficient session validation allows unauthorized access to protected resources. The vulnerability enables attackers to maintain persistent access to the router administration interface, potentially leading to complete network compromise.
From an operational standpoint, this vulnerability presents a severe risk to network security as it allows remote attackers to gain administrative privileges without physical access to the device or knowledge of network credentials. The attack vector is particularly dangerous because it can be executed remotely over the internet, making it accessible to any attacker with basic network connectivity. Once compromised, attackers can modify router settings, redirect traffic, install malicious firmware, or use the device as a pivot point for further attacks within the network. The impact extends beyond simple unauthorized access to include potential data exfiltration, network disruption, and establishment of persistent backdoors. This vulnerability aligns with ATT&CK technique T1078.004 for valid accounts and T1566 for credential harvesting, as it enables unauthorized access through session manipulation rather than traditional credential theft methods.
Mitigation strategies for this vulnerability should include immediate firmware updates from ASUS to address the session management flaw, implementation of network segmentation to limit exposure, and monitoring for suspicious HTTP header patterns in network traffic. Organizations should also consider disabling unnecessary web administration interfaces when not actively required, implementing strong access controls for router management, and conducting regular security assessments of network infrastructure. The vulnerability highlights the importance of proper session validation and secure authentication mechanisms in embedded web services, particularly in consumer-grade networking equipment where firmware updates may not be regularly applied by users. Network administrators should also implement intrusion detection systems capable of identifying anomalous header patterns associated with this specific attack vector.