A PHP application does not properly protect against the modification of variables from external sources, such as query parameters or cookies. This can expose the application to numerous weaknesses that would not exist otherwise.
REALIZATION: This weakness is caused during implementation of an architectural security tactic.
Common Consequences
Impact: Modify Application Data — Notes:
Potential Mitigations
Requirements: Carefully identify which variables can be controlled or influenced by an external user, and consider adopting a naming convention to emphasize when externally modifiable variables are being used. An application should be reluctant to trust variables that have been initialized outside of its trust boundary. Ensure adequate checking is performed when relying on input from outside a trust boundary. Do not allow your application to run with register_globals enabled. If you implement a register_globals emulator, be extremely careful of variable extraction, dynamic evaluation, and similar issues, since weaknesses in your emulation could allow external variable modification to take place even without register_globals. (N/A)
Applicable Platforms
PHP (N/A, Undetermined)
Demonstrative Examples
N/A
Notes
Relationship: This is a language-specific instance of Modification of Assumed-Immutable Data (MAID). This can be resultant from direct request (alternate path) issues. It can be primary to weaknesses such as PHP file inclusion, SQL injection, XSS, authentication bypass, and others.