An attacker manipulates variables used by an application to perform a
variet 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
