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.
Extended Description
For example, in PHP, calling extract() or import_request_variables()
without the proper arguments could allow arbitrary global variables to be
overwritten, including superglobals. Similar functionality might be possible
in other interpreted languages, including custom languages.
import request variables() buried in include files
makes post-disclosure analysis confusing
Potential Mitigations
Phase
Description
Use whitelists of variable names that can be extracted.
Consider refactoring your code to avoid extraction routines
altogether.
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.
Other Notes
In general, variable extraction can make control and data flow analysis
difficult to perform. For PHP, extraction can be used to provide
functionality similar to register_globals, which is frequently disabled in
production systems. Many PHP versions will overwrite superglobals in
extract/import_request_variables calls.
Weakness Ordinalities
Ordinality
Description
Primary
(where the
weakness exists independent of other weaknesses)
Description
