CVE-2018-10750 in DSL-3782
Summary
by MITRE
An issue was discovered on D-Link DSL-3782 EU 1.01 devices. An authenticated user can pass a long buffer as a 'staticGet' parameter to the '/userfs/bin/tcapi' binary (in the Diagnostics component) using the 'staticGet <node_name attr>' function and cause memory corruption. Furthermore, it is possible to redirect the flow of the program and execute arbitrary code.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 02/02/2020
The vulnerability identified as CVE-2018-10750 affects D-Link DSL-3782 EU 1.01 broadband routers and represents a critical buffer overflow flaw within the device's diagnostics component. This issue resides in the /userfs/bin/tcapi binary which handles the staticGet function for retrieving node attributes from the device's configuration tree. The vulnerability manifests when an authenticated user submits a specially crafted payload containing an excessively long buffer as the 'staticGet' parameter, which then gets processed by the tcapi binary without proper bounds checking.
The technical exploitation of this vulnerability stems from inadequate input validation within the diagnostics functionality of the router's firmware. When the staticGet function processes the malformed input, it fails to properly validate the length of the provided buffer, allowing an attacker to overwrite adjacent memory locations in the tcapi binary. This memory corruption directly leads to arbitrary code execution capabilities, as demonstrated by the ability to redirect program flow and inject malicious instructions into the router's execution context. The vulnerability is particularly concerning because it requires only authenticated access, meaning an attacker who has already gained user credentials can leverage this flaw to escalate privileges and take full control of the device.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with complete control over the affected router's functionality. This includes the ability to modify network configurations, redirect traffic, establish backdoors, and potentially use the compromised device as a pivot point for attacking other systems within the local network. The attack surface is further expanded due to the router's role as a gateway device, making it an attractive target for attackers seeking to establish persistent access to corporate or residential networks. From a security framework perspective, this vulnerability maps directly to CWE-121, which describes heap-based buffer overflow conditions, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as the exploitation involves executing arbitrary commands through the compromised binary.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates from D-Link, as the vendor has likely released patches addressing the buffer overflow condition. Network administrators should implement strict access controls and monitor for unauthorized authentication attempts, while also considering network segmentation to limit the potential impact of exploitation. Additional defensive measures include disabling unnecessary services, implementing robust firewall rules, and conducting regular security assessments of network infrastructure. The vulnerability highlights the importance of proper input validation and memory management in embedded systems, particularly in network devices where remote code execution capabilities can lead to significant compromise of entire network infrastructures. Organizations should also consider implementing intrusion detection systems to monitor for suspicious activity patterns that may indicate exploitation attempts against similar vulnerabilities in their network equipment.