{"@ID": "375", "@Name": "Returning a Mutable Object to an Untrusted Caller", "@Abstraction": "Base", "@Structure": "Simple", "@Status": "Draft", "Description": "The code sends non-cloned mutable data as a return value may result in that data being altered or deleted by the calling function.", "Related_Weaknesses": {"Related_Weakness": {"@Nature": "ChildOf", "@CWE_ID": "668", "@View_ID": "1000", "@Ordinal": "Primary"}}, "Weakness_Ordinalities": {"Weakness_Ordinality": {"Ordinality": "Primary"}}, "Applicable_Platforms": {"Language": [{"@Class": "Object-Oriented", "@Prevalence": "Undetermined"}, {"@Name": "C", "@Prevalence": "Undetermined"}, {"@Name": "C++", "@Prevalence": "Undetermined"}, {"@Name": "Java", "@Prevalence": "Undetermined"}, {"@Name": "C#", "@Prevalence": "Undetermined"}]}, "Modes_Of_Introduction": {"Introduction": {"Phase": "Implementation"}}, "Likelihood_Of_Exploit": "Medium", "Common_Consequences": {"Consequence": {"Scope": ["Access Control", "Integrity"], "Impact": "Modify Memory", "Note": "The muitable data could be altered or deleted by the calling function. If this data was not previously cloned, the class will then be using modified data which may violate assumptions about its internal state."}}, "Potential_Mitigations": {"Mitigation": [{"Phase": "Implementation", "Description": "Declare returned data which should not be altered as constant or immutable."}, {"Phase": "Implementation", "Description": "Clone all mutable data before returning references to it. This is the preferred mitigation. This way, regardless of what changes are made to the data, a valid copy is retained for use by the class."}]}, "Demonstrative_Examples": {"Demonstrative_Example": {"Intro_Text": "This class has a private list of patients, but provides a way to see the list :", "Example_Code": {"@Nature": "Bad", "@Language": "Java", "xhtml:div": {"xhtml:div": {"@style": "margin-left:1em;", "xhtml:br": null, "xhtml:div": {"@style": "margin-left:1em;", "#text": "return patientList;"}, "#text": "private PatientClass[] patientList = new PatientClass[50];public getPatients(...){}"}, "#text": "public class ClinicalTrial {}"}, "#text_blocks": ["public class ClinicalTrial {", "private PatientClass[] patientList = new PatientClass[50];", "public getPatients(...){", "return patientList;", "}", "}"]}, "Body_Text": "While this code only means to allow reading of the patient list, the getPatients() method returns a reference to the class's original patient list instead of a reference to a copy of the list. Any caller of this method can arbitrarily modify the contents of the patient list even though it is a private member of the class."}}, "Taxonomy_Mappings": {"Taxonomy_Mapping": [{"@Taxonomy_Name": "CLASP", "Entry_Name": "Mutable object returned"}, {"@Taxonomy_Name": "The CERT Oracle Secure Coding Standard for Java (2011)", "Entry_ID": "OBJ04-J", "Entry_Name": "Provide mutable classes with copy functionality to safely allow passing instances to untrusted code"}, {"@Taxonomy_Name": "The CERT Oracle Secure Coding Standard for Java (2011)", "Entry_ID": "OBJ05-J", "Entry_Name": "Defensively copy private mutable class members before returning their references"}, {"@Taxonomy_Name": "SEI CERT Perl Coding Standard", "Entry_ID": "EXP34-PL", "Entry_Name": "Do not modify $_ in list or sorting functions", "Mapping_Fit": "Imprecise"}, {"@Taxonomy_Name": "Software Fault Patterns", "Entry_ID": "SFP23", "Entry_Name": "Exposed Data"}]}, "References": {"Reference": {"@External_Reference_ID": "REF-18"}}, "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"}}}, "Content_History": {"Submission": {"Submission_Name": "CLASP", "Submission_Date": "2006-07-19", "Submission_Version": "Draft 3", "Submission_ReleaseDate": "2006-07-19"}, "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, Common_Consequences, Relationships, Other_Notes, 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 Name, Taxonomy_Mappings"}, {"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, Relationships, Taxonomy_Mappings"}, {"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, Taxonomy_Mappings"}, {"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 Demonstrative_Examples"}, {"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 Description, Other_Notes, Potential_Mitigations"}, {"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 Taxonomy_Mappings"}, {"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 Relationships, Taxonomy_Mappings"}, {"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 References"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2021-03-15", "Modification_Version": "4.4", "Modification_ReleaseDate": "2021-03-15", "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 Applicable_Platforms, Weakness_Ordinalities"}, {"Modification_Name": "CWE Content Team", "Modification_Organization": "MITRE", "Modification_Date": "2026-10-28", "Modification_Version": "5.0", "Modification_ReleaseDate": "2026-10-28", "Modification_Comment": "updated Common_Consequences, Description"}], "Previous_Entry_Name": {"@Date": "2010-09-27", "#text": "Passing Mutable Objects to an Untrusted Method"}}, "entry_type": "Weakness"}