This vulnerability allows network-adjacent attackers to bypass authentication on affected installations of NETGEAR AC1200 R6220 Firmware version 1.1.0.86 Smart WiFi Router. Authentication is not required to exploit this vulnerability. The specific flaw exists within the processing of path strings. By inserting a null byte into the path, the user can skip most authentication checks. An attacker can leverage this vulnerability to bypass authentication on the system. Was ZDI-CAN-8616.
The product does not properly handle null bytes or NUL characters when passing data between different representations or components.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Ac1200_r6220_firmware | Netgear | 1.1.0.86 (including) | 1.1.0.86 (including) |
A null byte (NUL character) can have different meanings across representations or languages. For example, it is a string terminator in standard C libraries, but Perl and PHP strings do not treat it as a terminator. When two representations are crossed - such as when Perl or PHP invokes underlying C functionality - this can produce an interaction error with unexpected results. Similar issues have been reported for ASP. Other interpreters written in C might also be affected. The poison null byte is frequently useful in path traversal attacks by terminating hard-coded extensions that are added to a filename. It can play a role in regular expression processing in PHP.