{"@ID": "611", "@Name": "Improper Restriction of XML External Entity Reference", "@Abstraction": "Base", "@Structure": "Simple", "@Status": "Draft", "@Diagram": "/data/images/CWE-611-Diagram.png", "Description": "The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.", "Related_Weaknesses": {"Related_Weakness": [{"@Nature": "ChildOf", "@CWE_ID": "610", "@View_ID": "1000", "@Ordinal": "Primary"}, {"@Nature": "ChildOf", "@CWE_ID": "610", "@View_ID": "1003", "@Ordinal": "Primary"}, {"@Nature": "PeerOf", "@CWE_ID": "441", "@View_ID": "1000"}]}, "Weakness_Ordinalities": {"Weakness_Ordinality": {"Ordinality": "Primary"}}, "Applicable_Platforms": {"Language": [{"@Class": "Not Language-Specific", "@Prevalence": "Undetermined"}, {"@Name": "XML", "@Prevalence": "Undetermined"}], "Technology": [{"@Class": "Not Technology-Specific", "@Prevalence": "Undetermined"}, {"@Class": "Web Based", "@Prevalence": "Undetermined"}]}, "Background_Details": {"Background_Detail": "XML documents optionally contain a Document Type Definition (DTD), which, among other features, enables the definition of XML entities. It is possible to define an entity by providing a substitution string in the form of a URI. The XML parser can access the contents of this URI and embed these contents back into the XML document for further processing."}, "Alternate_Terms": {"Alternate_Term": {"Term": "XXE", "Description": "An acronym used for the term \"XML eXternal Entities\""}}, "Modes_Of_Introduction": {"Introduction": {"Phase": "Implementation", "Note": "REALIZATION: This weakness is caused during implementation of an architectural security tactic."}}, "Common_Consequences": {"Consequence": [{"Scope": "Confidentiality", "Impact": ["Read Application Data", "Read Files or Directories"], "Note": "If the attacker is able to include a crafted DTD and a default entity resolver is enabled, the attacker may be able to access arbitrary files on the system. By submitting an XML   file that defines an external entity with a file:// URI, an attacker can cause the processing application to read the contents of a local file. For example, a URI such as \"file:///c:/winnt/win.ini\" designates (in Windows) the file C:\\Winnt\\win.ini, or file:///etc/passwd designates the password file in Unix-based systems. Once the content of the URI is read, it is fed back into the application that is processing the XML. This application may echo back the data (e.g., in an error message), thereby exposing the file contents."}, {"Scope": "Integrity", "Impact": "Bypass Protection Mechanism", "Note": "An attacker may supply a crafted DTD using URIs with schemes such as http://, forcing the application to make outgoing HTTP requests to servers that the attacker cannot reach directly, which can be used to bypass firewall restrictions; hide the source of attacks such as port scanning; or otherwise leverage the server's trust relationship with other entities."}, {"Scope": "Availability", "Impact": ["DoS: Resource Consumption (CPU)", "DoS: Resource Consumption (Memory)"], "Note": "The product could consume excessive CPU cycles or memory using a URI that points to a large file, or a device that always returns data such as /dev/random. Alternately, the URI could reference a file that contains many nested or recursive entity references to further slow down parsing."}]}, "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.)", "Effectiveness": "High"}}, "Potential_Mitigations": {"Mitigation": {"Phase": ["Implementation", "System Configuration"], "Description": "Many XML parsers and validators can be configured to disable external entity expansion."}}, "Observed_Examples": {"Observed_Example": [{"Reference": "CVE-2022-42745", "Description": "Recruiter software allows reading arbitrary files using XXE", "Link": "https://www.cve.org/CVERecord?id=CVE-2022-42745"}, {"Reference": "CVE-2005-1306", "Description": "A browser control can allow remote attackers to determine the existence of files via Javascript containing XML script.", "Link": "https://www.cve.org/CVERecord?id=CVE-2005-1306"}, {"Reference": "CVE-2012-5656", "Description": "XXE during SVG image conversion", "Link": "https://www.cve.org/CVERecord?id=CVE-2012-5656"}, {"Reference": "CVE-2012-2239", "Description": "XXE in PHP application allows reading the application's configuration file.", "Link": "https://www.cve.org/CVERecord?id=CVE-2012-2239"}, {"Reference": "CVE-2012-3489", "Description": "XXE in database server", "Link": "https://www.cve.org/CVERecord?id=CVE-2012-3489"}, {"Reference": "CVE-2012-4399", "Description": "XXE in rapid web application development framework allows reading arbitrary files.", "Link": "https://www.cve.org/CVERecord?id=CVE-2012-4399"}, {"Reference": "CVE-2012-3363", "Description": "XXE via XML-RPC request.", "Link": "https://www.cve.org/CVERecord?id=CVE-2012-3363"}, {"Reference": "CVE-2012-0037", "Description": "XXE in office document product using RDF.", "Link": "https://www.cve.org/CVERecord?id=CVE-2012-0037"}, {"Reference": "CVE-2011-4107", "Description": "XXE in web-based administration tool for database.", "Link": "https://www.cve.org/CVERecord?id=CVE-2011-4107"}, {"Reference": "CVE-2010-3322", "Description": "XXE in product that performs large-scale data analysis.", "Link": "https://www.cve.org/CVERecord?id=CVE-2010-3322"}, {"Reference": "CVE-2009-1699", "Description": "XXE in XSL stylesheet functionality in a common library used by some web browsers.", "Link": "https://www.cve.org/CVERecord?id=CVE-2009-1699"}]}, "Taxonomy_Mappings": {"Taxonomy_Mapping": [{"@Taxonomy_Name": "WASC", "Entry_ID": "43", "Entry_Name": "XML External Entities"}, {"@Taxonomy_Name": "Software Fault Patterns", "Entry_ID": "SFP24", "Entry_Name": "Tainted input to command"}]}, "Related_Attack_Patterns": {"Related_Attack_Pattern": {"@CAPEC_ID": "221"}}, "References": {"Reference": [{"@External_Reference_ID": "REF-496"}, {"@External_Reference_ID": "REF-497"}, {"@External_Reference_ID": "REF-498"}, {"@External_Reference_ID": "REF-499"}, {"@External_Reference_ID": "REF-500"}, {"@External_Reference_ID": "REF-501"}]}, "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": "Relationship", "#text": "CWE-918 (SSRF) and CWE-611 (XXE) are closely related, because they both involve web-related technologies and can launch outbound requests to unexpected destinations. However, XXE can be performed client-side, or in other contexts in which the software is not acting directly as a server, so the \"Server\" portion of the SSRF acronym does not necessarily apply."}}, "Content_History": {"Submission": {"Submission_Name": "Anonymous Tool Vendor (under NDA)", "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 Description, Relationships, Observed_Example, Other_Notes, Taxonomy_Mappings"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2010-02-16", "Modification_Version": "1.8", "Modification_ReleaseDate": "2010-02-16", "Modification_Comment": "updated Taxonomy_Mappings"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2010-09-27", "Modification_Version": "1.10", "Modification_ReleaseDate": "2010-09-27", "Modification_Comment": "updated Background_Details, Other_Notes"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2011-03-29", "Modification_Version": "1.12", "Modification_ReleaseDate": "2011-03-30", "Modification_Comment": "updated Name"}, {"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": "2013-02-21", "Modification_Version": "2.4", "Modification_ReleaseDate": "2013-02-21", "Modification_Comment": "updated Alternate_Terms, Applicable_Platforms, Background_Details, Common_Consequences, Description, Name, Observed_Examples, Potential_Mitigations, References, Relationship_Notes, Relationships, Taxonomy_Mappings"}, {"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": "2015-12-07", "Modification_Version": "2.9", "Modification_ReleaseDate": "2015-12-07", "Modification_Comment": "updated Relationships"}, {"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 Modes_of_Introduction, References, Relationships, Relevant_Properties"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2018-03-27", "Modification_Version": "3.1", "Modification_ReleaseDate": "2018-03-27", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2019-01-03", "Modification_Version": "3.2", "Modification_ReleaseDate": "2019-01-03", "Modification_Comment": "updated Related_Attack_Patterns"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2019-06-20", "Modification_Version": "3.3", "Modification_ReleaseDate": "2019-06-20", "Modification_Comment": "updated Name, Type"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2019-09-19", "Modification_Version": "3.4", "Modification_ReleaseDate": "2019-09-19", "Modification_Comment": "updated Relationships"}, {"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 Applicable_Platforms, 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": "2021-07-20", "Modification_Version": "4.5", "Modification_ReleaseDate": "2021-07-20", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2021-10-28", "Modification_Version": "4.6", "Modification_ReleaseDate": "2021-10-28", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2022-06-28", "Modification_Version": "4.8", "Modification_ReleaseDate": "2022-06-28", "Modification_Comment": "updated Relationships"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2023-01-31", "Modification_Version": "4.10", "Modification_ReleaseDate": "2023-01-31", "Modification_Comment": "updated Alternate_Terms, Common_Consequences, Description"}, {"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 Detection_Factors, References, 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": "2023-10-26", "Modification_Version": "4.13", "Modification_ReleaseDate": "2023-10-26", "Modification_Comment": "updated Observed_Examples"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2025-09-09", "Modification_Version": "4.18", "Modification_ReleaseDate": "2025-09-09", "Modification_Comment": "updated References"}, {"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 Applicable_Platforms, Background_Details, Common_Consequences, Description, Diagram, Relationships, Weakness_Ordinalities"}], "Previous_Entry_Name": [{"@Date": "2011-03-29", "#text": "Information Leak Through XML External Entity File Disclosure"}, {"@Date": "2013-02-21", "#text": "Information Exposure Through XML External Entity Reference"}, {"@Date": "2019-06-20", "#text": "Improper Restriction of XML External Entity Reference ('XXE')"}]}}