CWE-621 Detail

The product uses external input to determine the names of variables into which information is extracted, without verifying that the names of the specified variables are valid. This could cause the program to overwrite unintended variables.

For example, in PHP, extraction can be used to provide functionality similar to register_globals, a dangerous functionality that is frequently disabled in production systems. Calling extract() or import_request_variables() without the proper arguments could allow arbitrary global variables to be overwritten, including superglobals.

Similar functionality is possible in other interpreted languages, including custom languages.

Modes Of Introduction

Implementation

Applicable Platforms

Language

Name: PHP (Undetermined)

Common Consequences

Observed Examples

Potential Mitigations

Phases : Implementation
Use allowlists of variable names that can be extracted.
Phases : Implementation
Consider refactoring your code to avoid extraction routines altogether.
Phases : Implementation
In PHP, call extract() with options such as EXTR_SKIP and EXTR_PREFIX_ALL; call import_request_variables() with a prefix argument. Note that these capabilities are not present in all PHP versions.

Vulnerability Mapping Notes

Justification : This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comment : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

NotesNotes

Probably under-reported for PHP. Seems under-studied for other interpreted languages.

Submission

Modifications