CVE-2016-10699 in DSL-2740E
Summary
by MITRE
D-Link DSL-2740E 1.00_BG_20150720 devices are prone to persistent XSS attacks in the username and password fields: a remote unauthenticated user may craft logins and passwords with script tags in them. Because there is no sanitization in the input fields, an unaware logged-in administrator may be a victim when checking the router logs.
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Analysis
by VulDB Data Team • 01/21/2021
The vulnerability identified as CVE-2016-10699 affects D-Link DSL-2740E routers running firmware version 1.00_BG_20150720, representing a critical persistent cross-site scripting weakness that undermines the security posture of network infrastructure devices. This flaw exists within the router's web-based management interface where user credentials are processed without proper input sanitization, creating an exploitable condition that allows attackers to inject malicious scripts into the authentication fields. The vulnerability specifically targets the username and password input parameters, which are processed and stored in the router's logs without any form of validation or sanitization, making it susceptible to persistent XSS attacks.
The technical nature of this vulnerability aligns with CWE-79, which describes cross-site scripting flaws where untrusted data is incorporated into web pages without proper validation or encoding. The attack vector is particularly concerning because it operates through a persistent mechanism rather than a reflected XSS attack, meaning that the malicious script remains embedded in the router's log files and executes whenever an administrator views these logs. This creates a sophisticated attack scenario where the malicious code can target any administrator who accesses the router's administrative interface to review login attempts or system logs.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking, as it provides attackers with a potential foothold for more extensive network compromise. When an administrator accesses the router logs to investigate failed login attempts, the malicious scripts embedded in the username and password fields execute within the administrator's browser context, potentially leading to credential theft, session manipulation, or even remote code execution depending on the administrator's privileges and browser security settings. The persistent nature of this vulnerability means that once an attacker successfully injects malicious code, it remains active until the router is rebooted or the logs are manually cleared, providing extended attack windows.
From a threat modeling perspective, this vulnerability maps to multiple ATT&CK techniques including T1190 for exploitation of vulnerabilities, T1071.001 for application layer protocol usage, and T1531 for lateral movement through compromised administrative interfaces. The attack chain typically begins with an unauthenticated attacker crafting malicious credentials containing script tags, which are then logged by the router without sanitization. When administrators review these logs, their browsers execute the embedded scripts, potentially leading to full administrative compromise of the network device. Organizations should implement immediate mitigations including firmware updates, network segmentation, and monitoring of administrative log access patterns to detect potential exploitation attempts.
The broader implications of this vulnerability highlight the critical importance of input validation and sanitization in network infrastructure devices, particularly those with web-based management interfaces that are frequently accessed by privileged users. The vulnerability demonstrates how seemingly minor oversights in input handling can create persistent security risks that extend far beyond the initial attack surface, emphasizing the need for comprehensive security testing and validation of all user input processing within network appliances. Organizations should prioritize firmware updates for affected devices and implement network monitoring to detect potential exploitation attempts targeting administrative interfaces of similar network equipment.