DETECTION OVERVIEW
Risk Factors
PHP is a popular open-source scripting language. Threat groups, such as TellYouThePass, have been known to exploit this vulnerability, and the code is publicly available. An unauthenticated attacker can attempt to run arbitrary commands and gain access to sensitive files.
Kill Chain
Risk Score
87
An attacker can prepend the string “%AD” onto the query string of an HTTP request line, which is then downcasted from Unicode to ASCII. This vulnerability causes an encoding conversion issue where PHP misinterprets certain URI parameters as PHP options. The misinterpreted PHP option enables an attacker to manipulate the input to remotely run malicious commands on the target system. Depending on the objective, the attacker can access sensitive files or launch further attacks on the server.
Install relevant patches for affected software versions
Sanitize URL input to PHP applications
Review HTTP daemon configuration files for PHP