Last revision (mm/dd/yy): 04/23/2009
This attack aims to modify application settings in order to cause misleading data or advantages on the attacker's behalf. He may manipulate values in the system and manage specific user resources of the application or affect its functionalities.
An attacker can exploit several functionalities of the application using this attack technique, but it would not possible to describe all the ways of exploration, due to innumerable options that attacker may use to control the system values.
Using this attack technique, it is possible to manipulate settings by changing the application functions, such as calls to the database, blocking access to external libraries, and/or modification log files.
An attacker needs to identify the variables without input validation or those improperly encapsulated to obtain success in the attack.
The following example was based on those found in the Individual CWE Dictionary Definition (Setting Manipulation-15).
Consider the following piece of Java code:
… conn.setCatalog(request.getParameter(“catalog”)); ...
This fragment reads the string “catalog” from “HttpServletRequest” and sets it as the active catalog for a database connection. An attacker could manipulate this information and cause a connection error or unauthorized access to other catalogs.
Example 2 – Block Access to Libraries
The attacker has the privileges to block application access to external libraries to execute this attack. It is necessary to discover what external libraries are accessed by the application and block them. The attacker needs to observe if the behavior of the system goes into an insecure/inconsistent state.
In this case the application uses a third party cryptographic random number generation library to generate user Session IDs. An attacker may block access to this library by renaming it. Then the application will use the weak pseudo random number generation library. The attacker can use this weakness to predict the Session ID user; he/she attempts to perform elevation of privilege escalation and gains access to the user's account.
For more details about this attack, see: http://capec.mitre.org/data/definitions/96.html