Name Subverting Environment Variable Values
Summary The attacker directly or indirectly modifies environment variables used by or controlling the target software. The attacker's goal is to cause the target software to deviate from its expected operation in a manner that benefits the attacker.
Prerequisites 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 attacker may attempt to manipulate that variable.
Solutions Protect environment variables against unauthorized read and write access. Protect the configuration files which contain environment variables against illegitimate read and write access. Assume all input is malicious. Create a white list that defines all valid input to the software system based on the requirements specifications. Input that does not match against the white list should not be permitted to enter into the system. Apply the least privilege principles. If a process has no legitimate reason to read an environment variable do not give that privilege.
Related Weaknesses
CWE ID Description
CWE-15 External Control of System or Configuration Setting
CWE-20 Improper Input Validation
CWE-73 External Control of File Name or Path
CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-200 Information Exposure
CWE-285 Improper Authorization
CWE-302 Authentication Bypass by Assumed-Immutable Data
CWE-353 Missing Support for Integrity Check
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