CAPEC-13: Subverting Environment Variable Values

The adversary directly or indirectly modifies environment variables used by or controlling the target software. The adversary's goal is to cause the target software to deviate from its expected operation in a manner that benefits the adversary.
Extended Description

If access control mechanisms are absent or misconfigured, a user may be able to access resources that are intended only for higher level users. An adversary may be able to exploit this to utilize a less trusted account to gain information and perform activities reserved for more trusted accounts.

This attack differs from privilege escalation and other privilege stealing attacks in that the adversary never actually escalates their privileges but instead is able to use a lesser degree of privilege to access resources that should be (but are not) reserved for higher privilege accounts. Likewise, the adversary does not exploit trust or subvert systems - all control functionality is working as configured but the configuration does not adequately protect sensitive resources at an appropriate level.

Severity :

Very High

Possibility :


Type :


This table shows the other attack patterns and high level categories that are related to this attack pattern.

  • An environment variable is accessible to the user.
  • An environment variable used by the application can be tainted with user supplied data.
  • Input data used in an environment variable is not validated properly.
  • The variables encapsulation is not done properly. For instance setting a variable as public in a class makes it visible and an adversary may attempt to manipulate that variable.
Skills required

This table shows the other attack patterns and high level categories that are related to this attack pattern.

  • Low In a web based scenario, the client controls the data that it submitted to the server. So anybody can try to send malicious data and try to bypass the authentication mechanism.
  • High Some more advanced attacks may require knowledge about protocols and probing technique which help controlling a variable. The malicious user may try to understand the authentication mechanism in order to defeat it.

Visit for more details.