CVE-2020-9534 in DIR-615Jx10
Summary
by MITRE
fmwlan.c on D-Link DIR-615Jx10 devices has a stack-based buffer overflow via the formWlanSetup webpage parameter when f_radius_ip1 is malformed.
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Analysis
by VulDB Data Team • 04/07/2024
The vulnerability identified as CVE-2020-9534 represents a critical stack-based buffer overflow flaw in the firmware of D-Link DIR-615Jx10 wireless routers. This issue resides within the fmwlan.c source file and specifically targets the formWlanSetup webpage parameter processing. The vulnerability manifests when the f_radius_ip1 parameter contains malformed input data, creating an exploitable condition that could allow remote attackers to execute arbitrary code on the affected device. The stack-based buffer overflow occurs due to insufficient input validation and bounds checking within the wireless configuration handling logic, making it a prime target for privilege escalation attacks.
The technical exploitation of this vulnerability follows the patterns outlined in CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations on the program stack. The flaw specifically affects the wireless network configuration interface of the router, where user-supplied input for the radius_ip1 parameter is directly processed without adequate sanitization. This parameter is typically used to configure Remote Authentication Dial-In User Service (RADIUS) servers for wireless network authentication, making it a legitimate configuration field that attackers can manipulate to trigger the overflow condition.
The operational impact of CVE-2020-9534 extends beyond simple code execution, as it provides attackers with potential full system compromise of the affected D-Link routers. Successful exploitation could enable attackers to gain root access to the device, allowing them to modify network configurations, intercept wireless traffic, or establish persistent backdoors. This vulnerability directly maps to ATT&CK technique T1059.007 for command and control through web shell execution, and T1068 for local privilege escalation. The affected devices operate in a network environment where they serve as gateways for wireless clients, making them attractive targets for attackers seeking to establish persistent access points within corporate or residential networks.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from D-Link, as the company has released patches addressing the buffer overflow condition. Network administrators should implement network segmentation and monitoring to detect anomalous traffic patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of input validation and bounds checking in embedded systems, as outlined in the OWASP Top Ten security principles and the NIST Cybersecurity Framework. Additionally, implementing web application firewalls and intrusion detection systems can help prevent exploitation attempts by blocking malformed requests targeting the vulnerable formWlanSetup parameter. Regular security assessments of network infrastructure, particularly for legacy devices, remain crucial for identifying similar buffer overflow vulnerabilities in other embedded systems that may not have received timely security updates.