Modification of Assumed-Immutable Data (MAID)

Description

This occurs when a particular input is critical enough to the functioning of the application that it should not be modifiable at all, but it is. Certain resources are often assumed to be immutable when they are not, such as hidden form fields in web applications, cookies, and reverse DNS lookups.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

In the code excerpt below, an array returned by a Java method is modified despite the fact that arrays are mutable.

String[] colors = car.getAllPossibleColors();
colors[0] = "Red";

See Also