{"@ID": "624", "@Name": "Executable Regular Expression Error", "@Abstraction": "Base", "@Structure": "Simple", "@Status": "Incomplete", "Description": "The product uses a regular expression that either (1) contains an executable component with user-controlled inputs, or (2) allows a user to enable execution by inserting pattern modifiers.", "Extended_Description": "Case (2) is possible in the PHP preg_replace() function, and possibly in other languages when a user-controlled input is inserted into a string that is later parsed as a regular expression.", "Related_Weaknesses": {"Related_Weakness": [{"@Nature": "ChildOf", "@CWE_ID": "77", "@View_ID": "1000", "@Ordinal": "Primary"}, {"@Nature": "ChildOf", "@CWE_ID": "77", "@View_ID": "1305", "@Ordinal": "Primary"}, {"@Nature": "ChildOf", "@CWE_ID": "77", "@View_ID": "1340", "@Ordinal": "Primary"}]}, "Weakness_Ordinalities": {"Weakness_Ordinality": {"Ordinality": "Primary"}}, "Applicable_Platforms": {"Language": [{"@Name": "PHP", "@Prevalence": "Undetermined"}, {"@Name": "Perl", "@Prevalence": "Undetermined"}]}, "Modes_Of_Introduction": {"Introduction": {"Phase": "Implementation"}}, "Common_Consequences": {"Consequence": {"Scope": ["Confidentiality", "Integrity", "Availability"], "Impact": "Execute Unauthorized Code or Commands"}}, "Detection_Methods": {"Detection_Method": {"@Detection_Method_ID": "DM-14", "Method": "Automated Static Analysis", "Description": "Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect \"sources\" (origins of input) with \"sinks\" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)"}}, "Potential_Mitigations": {"Mitigation": {"Phase": "Implementation", "Description": "The regular expression feature in some languages allows inputs to be quoted or escaped before insertion, such as \\Q and \\E in Perl."}}, "Observed_Examples": {"Observed_Example": [{"Reference": "CVE-2006-2059", "Description": "Executable regexp in PHP by inserting \"e\" modifier into first argument to preg_replace", "Link": "https://www.cve.org/CVERecord?id=CVE-2006-2059"}, {"Reference": "CVE-2005-3420", "Description": "Executable regexp in PHP by inserting \"e\" modifier into first argument to preg_replace", "Link": "https://www.cve.org/CVERecord?id=CVE-2005-3420"}, {"Reference": "CVE-2006-2878", "Description": "Complex curly syntax inserted into the replacement argument to PHP preg_replace(), which uses the \"/e\" modifier", "Link": "https://www.cve.org/CVERecord?id=CVE-2006-2878"}, {"Reference": "CVE-2006-2908", "Description": "Function allows remote attackers to execute arbitrary PHP code via the username field, which is used in a preg_replace function call with a /e (executable) modifier.", "Link": "https://www.cve.org/CVERecord?id=CVE-2006-2908"}]}, "Taxonomy_Mappings": {"Taxonomy_Mapping": {"@Taxonomy_Name": "Software Fault Patterns", "Entry_ID": "SFP24", "Entry_Name": "Tainted input to command"}}, "Mapping_Notes": {"Usage": "Allowed", "Rationale": "This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.", "Comments": "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.", "Reasons": {"Reason": {"@Type": "Acceptable-Use"}}}, "Notes": {"Note": {"@Type": "Research Gap", "#text": "Under-studied. The existing PHP reports are limited to highly skilled researchers, but there are few examples for other languages. It is suspected that this is under-reported for all languages. Usability factors might make it more prevalent in PHP, but this theory has not been investigated."}}, "Content_History": {"Submission": {"Submission_Name": "CWE Content Team", "Submission_Organization": "MITRE", "Submission_Date": "2007-05-07", "Submission_Version": "Draft 6", "Submission_ReleaseDate": "2007-05-07"}, "Modification": [{"Modification_Name": "Eric Dalci", "Modification_Organization": "Cigital", "Modification_Date": "2008-07-01", "Modification_Version": "1.0", "Modification_ReleaseDate": "2008-09-09", "Modification_Comment": "updated Time_of_Introduction"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2008-09-08", "Modification_Version": "1.0", "Modification_ReleaseDate": "2008-09-09", "Modification_Comment": "updated Applicable_Platforms, Relationships, Observed_Example"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2008-10-14", "Modification_Version": "1.0.1", "Modification_ReleaseDate": "2008-10-14", "Modification_Comment": "updated Description"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2011-06-01", "Modification_Version": "1.13", "Modification_ReleaseDate": "2011-06-01", "Modification_Comment": "updated Common_Consequences"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2012-05-11", "Modification_Version": "2.2", "Modification_ReleaseDate": "2012-05-15", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2012-10-30", "Modification_Version": "2.3", "Modification_ReleaseDate": "2012-10-30", "Modification_Comment": "updated Potential_Mitigations"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2014-06-23", "Modification_Version": "2.7", "Modification_ReleaseDate": "2014-06-23", "Modification_Comment": "updated Observed_Examples"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2014-07-30", "Modification_Version": "2.8", "Modification_ReleaseDate": "2014-07-31", "Modification_Comment": "updated Relationships, Taxonomy_Mappings"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2017-11-08", "Modification_Version": "3.0", "Modification_ReleaseDate": "2017-11-08", "Modification_Comment": "updated Observed_Examples"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2020-02-24", "Modification_Version": "4.0", "Modification_ReleaseDate": "2020-02-24", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2020-08-20", "Modification_Version": "4.2", "Modification_ReleaseDate": "2020-08-20", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2020-12-10", "Modification_Version": "4.3", "Modification_ReleaseDate": "2020-12-10", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2023-04-27", "Modification_Version": "4.11", "Modification_ReleaseDate": "2023-04-27", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2023-06-29", "Modification_Version": "4.12", "Modification_ReleaseDate": "2023-06-29", "Modification_Comment": "updated Mapping_Notes"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2025-12-11", "Modification_Version": "4.19", "Modification_ReleaseDate": "2025-12-11", "Modification_Comment": "updated Detection_Factors, Weakness_Ordinalities"}]}}