Description

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.

Modes of Introduction:

– Implementation

Related Weaknesses

CWE-914
CWE-471

Consequences

Integrity: Modify Application Data

An attacker could modify sensitive data or program variables.

Potential Mitigations

Phase: Implementation

Description: 

Use allowlists of variable names that can be extracted.

Phase: Implementation

Description: 

Consider refactoring your code to avoid extraction routines altogether.

Phase: Implementation

Description: 

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.

CVE References

• CVE-2006-7135
  • extract issue enables file inclusion

• CVE-2006-7079
  • extract used for register_globals compatibility layer, enables path traversal

• CVE-2007-0649
  • extract() buried in include files makes post-disclosure analysis confusing; original report had seemed incorrect.

• CVE-2006-6661
  • extract() enables static code injection

• CVE-2006-2828
  • import_request_variables() buried in include files makes post-disclosure analysis confusing