Vulnerabilities > CVE-2020-15634 - Use of Externally-Controlled Format String vulnerability in Netgear R6700 Firmware
Attack vector
ADJACENT_NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
PARTIAL Integrity impact
PARTIAL Availability impact
PARTIAL Summary
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6700 routers with firmware 1.0.4.84_10.0.58. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of string table file uploads. The issue results from the lack of proper validation of a user-supplied string before using it as a format specifier. An attacker can leverage this vulnerability to execute code in the context of the web server. Was ZDI-CAN-9755.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Format String Injection An attacker includes formatting characters in a string input field on the target application. Most applications assume that users will provide static text and may respond unpredictably to the presence of formatting character. For example, in certain functions of the C programming languages such as printf, the formatting character %s will print the contents of a memory location expecting this location to identify a string and the formatting character %n prints the number of DWORD written in the memory. An attacker can use this to read or write to memory locations or files, or simply to manipulate the value of the resulting text in unexpected ways. Reading or writing memory may result in program crashes and writing memory could result in the execution of arbitrary code if the attacker can write to the program stack.
- String Format Overflow in syslog() This attack targets the format string vulnerabilities in the syslog() function. An attacker would typically inject malicious input in the format string parameter of the syslog function. This is a common problem, and many public vulnerabilities and associated exploits have been posted.