Modification of Assumed-Immutable Data (MAID)

Opis

The product does not properly protect an assumed-immutable element from being modified by an attacker.

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.

Skutki

• Integrity

  Modify Application Data

  Common data types that are attacked are environment variables, web application parameters, and HTTP headers.

• Integrity

  Unexpected State

Zapobieganie

• Architecture and Design, Operation, Implementation

  When the data is stored or transmitted through untrusted sources that could modify the data, implement integrity checks to detect unauthorized modification, or store/transmit the data in a trusted location that is free from external influence.

Przykłady podatności

• CVE-2002-1757 Relies on $PHP_SELF variable for authentication.
• CVE-2005-1905 Gain privileges by modifying assumed-immutable code addresses that are accessed by a driver.

Słabość nadrzędna

• CWE-664 Improper Control of a Resource Through its Lifetime

Słabości podrzędne

• CWE-472 External Control of Assumed-Immutable Web Parameter
• CWE-473 PHP External Variable Modification
• CWE-607 Public Static Final Field References Mutable Object

Kiedy powstaje

• Implementation
• Architecture and Design

Dotyczy

Not Language-Specific, Not Technology-Specific, Web Based

Uwagi

MAID issues can be primary to many other weaknesses, and they are a major factor in languages that provide easy access to internal program constructs, such as PHP's register_globals and similar features. However, MAID issues can also be resultant from weaknesses that modify internal state; for example, a program might validate some data and store it in memory, but a buffer overflow could overwrite that validated data, leading to a change in program logic.

There are many examples where the MUTABILITY property is a major factor in a vulnerability.