CVE-2013-5703 in Vigor 2700 router
Summary
by MITRE
The DrayTek Vigor 2700 router 2.8.3 allows remote attackers to execute arbitrary JavaScript code, and modify settings or the DNS cache, via a crafted SSID value that is not properly handled during insertion into the sWlessSurvey value in variables.js.
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Analysis
by VulDB Data Team • 08/16/2024
The vulnerability CVE-2013-5703 represents a critical cross-site scripting flaw in DrayTek Vigor 2700 router firmware version 2.8.3, classified under CWE-79 as improper neutralization of input during web output. This vulnerability exists within the wireless survey functionality where the router fails to properly sanitize user-supplied SSID values before incorporating them into the sWlessSurvey variable within the variables.js JavaScript file. The flaw enables remote attackers to inject malicious JavaScript code through crafted SSID inputs, creating a persistent XSS vector that can be exploited without authentication. The vulnerability stems from insufficient input validation and output encoding mechanisms in the web interface's wireless configuration handling code.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious SSID value containing JavaScript payload that gets embedded into the sWlessSurvey variable. When the router processes this malformed input during wireless network scanning or survey operations, the JavaScript code becomes executable within the context of the web interface. This allows attackers to execute arbitrary commands on the router with the privileges of the web interface user, potentially leading to complete system compromise. The vulnerability affects the router's wireless management functionality and can be leveraged to modify router settings, manipulate the DNS cache, or redirect traffic through malicious DNS servers. The attack vector is particularly concerning as it requires no authentication and can be initiated remotely, making it a significant threat to network security.
The operational impact of CVE-2013-5703 extends beyond simple code execution to encompass complete network compromise and persistent backdoor access. An attacker could use this vulnerability to establish persistent access to the router, modify network configurations, redirect DNS queries to malicious servers, or even create a botnet node for further attacks. The vulnerability affects both corporate and residential networks, as the DrayTek Vigor 2700 is widely deployed in small to medium business environments. The flaw particularly impacts the router's ability to maintain network integrity and security, as it allows attackers to manipulate the wireless survey functionality that is critical for network management and monitoring. The vulnerability also poses risks to user privacy and data confidentiality, as attackers could potentially intercept network traffic or modify network settings to facilitate further attacks.
Mitigation strategies for CVE-2013-5703 should include immediate firmware updates from DrayTek to address the XSS vulnerability, as well as network segmentation and monitoring to detect suspicious wireless activity. Organizations should implement network access controls to limit access to router management interfaces and establish robust network monitoring to detect unauthorized configuration changes. The vulnerability highlights the importance of input validation and output encoding in web applications, aligning with ATT&CK technique T1059.007 for command and scripting interpreter. Security professionals should also consider implementing web application firewalls to detect and block malicious SSID inputs, and conduct regular vulnerability assessments of network infrastructure to identify similar input validation flaws. Additionally, network administrators should disable unnecessary wireless features and ensure that router management interfaces are not accessible from untrusted networks to minimize the attack surface.