Vulnerabilities > CVE-2017-10720 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Ishekar Endoscope Camera Firmware
Summary
Recently it was discovered as a part of the research on IoT devices in the most recent firmware for Shekar Endoscope that the desktop application used to connect to the device suffers from a stack overflow if more than 26 characters are passed to it as the Wi-Fi name. This application is installed on the device and an attacker who can provide the right payload can execute code on the user's system directly. Any breach of this system can allow an attacker to get access to all the data that the user has access too. The application uses a dynamic link library(DLL) called "avilib.dll" which is used by the application to send binary packets to the device that allow to control the device. One such action that the DLL provides is change password in the function "sendchangename" which allows a user to change the Wi-Fi name on the device. This function calls a sub function "sub_75876EA0" at address 0x758784F8. The function determines which action to execute based on the parameters sent to it. The "sendchangename" passes the datastring as the second argument which is the name we enter in the textbox and integer 1 as first argument. The rest of the 3 arguments are set to 0. The function "sub_75876EA0" at address 0x75876F19 uses the first argument received and to determine which block to jump to. Since the argument passed is 1, it jumps to 0x75876F20 and proceeds from there to address 0x75876F56 which calculates the length of the data string passed as the first parameter. This length and the first argument are then passed to the address 0x75877001 which calls the memmove function which uses a stack address as the destination where the password typed by us is passed as the source and length calculated above is passed as the number of bytes to copy which leads to a stack overflow.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| OS | 1 | |
| Hardware | 1 |
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Buffer Overflow via Environment Variables This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
- Overflow Buffers Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an attacker. As a consequence, an attacker is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the attackers' choice.
- Client-side Injection-induced Buffer Overflow This type of attack exploits a buffer overflow vulnerability in targeted client software through injection of malicious content from a custom-built hostile service.
- Filter Failure through Buffer Overflow In this attack, the idea is to cause an active filter to fail by causing an oversized transaction. An attacker may try to feed overly long input strings to the program in an attempt to overwhelm the filter (by causing a buffer overflow) and hoping that the filter does not fail securely (i.e. the user input is let into the system unfiltered).
- MIME Conversion An attacker exploits a weakness in the MIME conversion routine to cause a buffer overflow and gain control over the mail server machine. The MIME system is designed to allow various different information formats to be interpreted and sent via e-mail. Attack points exist when data are converted to MIME compatible format and back.