Vulnerabilities > CVE-2017-8416 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Dlink Dcs-1100 Firmware and Dcs-1130 Firmware
Summary
An issue was discovered on D-Link DCS-1100 and DCS-1130 devices. The device runs a custom daemon on UDP port 5978 which is called "dldps2121" and listens for broadcast packets sent on 255.255.255.255. This daemon handles custom D-Link UDP based protocol that allows D-Link mobile applications and desktop applications to discover D-Link devices on the local network. The binary processes the received UDP packets sent from any device in "main" function. One path in the function traverses towards a block of code that processing of packets which does an unbounded copy operation which allows to overflow the buffer. The custom protocol created by Dlink follows the following pattern: Packetlen, Type of packet; M=MAC address of device or broadcast; D=Device Type;C=base64 encoded command string;test=1111 We can see at address function starting at address 0x0000DBF8 handles the entire UDP packet and performs an insecure copy using strcpy function at address 0x0000DC88. This results in overflowing the stack pointer after 1060 characters and thus allows to control the PC register and results in code execution. The same form of communication can be initiated by any process including an attacker process on the mobile phone or the desktop and this allows a third-party application on the device to execute commands on the device without any authentication by sending just 1 UDP packet with custom base64 encoding.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| OS | 2 | |
| Hardware | 2 |
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.