CVE-2017-8412 in DCS-1100
Summary
by MITRE
An issue was discovered on D-Link DCS-1100 and DCS-1130 devices. The device has a custom binary called mp4ts under the /var/www/video folder. It seems that this binary dumps the HTTP VERB in the system logs. As a part of doing that it retrieves the HTTP VERB sent by the user and uses a vulnerable sprintf function at address 0x0000C3D4 in the function sub_C210 to copy the value into a string and then into a log file. Since there is no bounds check being performed on the environment variable at address 0x0000C360 this results in a stack overflow and overwrites the PC register allowing an attacker to execute buffer overflow or even a command injection attack.
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Analysis
by VulDB Data Team • 10/15/2023
The vulnerability identified in CVE-2017-8412 affects D-Link DCS-1100 and DCS-1130 network video surveillance devices, representing a critical security flaw that enables remote code execution through improper input validation. These devices are commonly deployed in enterprise and residential security environments, making this vulnerability particularly concerning from a cybersecurity perspective. The issue stems from a custom binary named mp4ts located within the /var/www/video directory structure of the affected devices, which processes HTTP requests and logs information about them. This binary serves as a critical component in the device's web interface functionality, handling video streaming and related HTTP communications.
The technical flaw manifests through a classic stack-based buffer overflow vulnerability within the mp4ts binary's sub_C210 function at address 0x0000C3D4. The vulnerability occurs when the binary processes HTTP VERB information through a vulnerable sprintf function call that lacks proper bounds checking mechanisms. Specifically, the function retrieves HTTP VERB data from an environment variable located at address 0x0000C360 without implementing adequate input validation or size constraints. This absence of bounds checking creates a deterministic stack overflow condition where attacker-controlled data can overwrite adjacent memory locations, including the program counter register that controls execution flow. The vulnerability directly maps to CWE-121, which describes stack-based buffer overflow conditions where insufficient boundary checking allows attackers to overwrite adjacent stack memory.
The operational impact of this vulnerability extends beyond simple buffer overflow exploitation to encompass full remote code execution capabilities, making it a severe threat vector for attackers targeting these surveillance devices. An attacker can leverage this vulnerability to execute arbitrary commands on the affected devices, potentially gaining complete control over the surveillance system. The attack surface is particularly dangerous because it requires no authentication to exploit, meaning anyone with network access to the device can potentially compromise it. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as it enables attackers to execute shell commands through the overflowed binary. The compromised devices could then be used for various malicious activities including data exfiltration, as a pivot point for network reconnaissance, or to establish persistent access to the target network.
Mitigation strategies for CVE-2017-8412 should focus on immediate firmware updates from D-Link to address the underlying buffer overflow vulnerability in the mp4ts binary. Organizations should implement network segmentation to isolate these surveillance devices from critical network segments and deploy network monitoring solutions to detect unusual traffic patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation and bounds checking in embedded systems, particularly those handling network communications. Security teams should also consider implementing web application firewalls to filter potentially malicious HTTP VERB data and regularly audit device configurations to ensure that unnecessary services remain disabled. Additionally, the incident highlights the critical need for secure coding practices in embedded environments, as the vulnerability could have been prevented through proper implementation of safe string handling functions and comprehensive input validation procedures.