An attacker manipulates variables used by an application to perform a variety of possible attacks. This can either be performed through the manipulation of function call parameters or by manipulating external variables, such as environment variables, that are used by an application. Changing variable values is usually undertaken as part of another attack; for example, a path traversal (inserting relative path modifiers) or buffer overflow (enlarging a variable value beyond an application's ability to store it).
Attack Prerequisites
The targeted application must rely on external variables (e.g. environment variables) or user-controlled variables (e.g. call parameters) in such a way that malicious manipulation of them can subvert functionality.
Resources Required
The attacker must be able to manipulate the targeted variable. For some variables, such as URL-encoded parameters in a web call, this is very simple. For others, such as a system's environment variables, this can require additional resources or capabilities.
Solutions and Mitigations
Design: Range, size and value and consistency verification for any arguments supplied to application from external sources and devise appropriate error response.
Design: Ensure that variables that should not be manipulated by a user are not accessible to them.
Description
