This attack aims to modify application settings in order to cause data misleading or advantages on user behalf. He may manipulate values in the system and manages specific resources user by application or affects 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 improperly encapsulated to obtain success in the attack.
The following example was based on the ones 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 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 discover what external libraries are accessed by application and block it. The attacker needs to observe if behavior of the system goes into an insecure/inconsistent state.
In this case the application uses a third party cryptographic random number generation library that used in generation of user session ids. An attacker may block to access this library by renaming it. Then an application will be 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 user’s account.
For more details about this attack, see: http://capec.mitre.org/data/definitions/96.html
http://cwe.mitre.org/data/definitions/15.html - Setting Manipulation
http://capec.mitre.org/data/definitions/13.html - Subverting Environment Variable Values
http://capec.mitre.org/data/definitions/96.html - Block Access to Libraries