Improper Restriction of Operations within the Bounds of a Memory Buffer
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.
CWE-119 - Buffer Overflow
Buffer overflow attacks involve data transit and operations exceeding the restricted memory buffer, thereby corrupting or overwriting data in adjacent memory locations. Such overflow allows the attacker to run arbitrary code or manipulate the existing code to cause privilege escalation, data breach, denial of service, system crash and even complete system compromise. Given that languages such as C and C++ lack default safeguards against overwriting or accessing data in their memory, applications utilizing these languages are most susceptible to buffer overflows attacks.