CVE-2024-23649
Published: 24 January 2024
Summary
CVE-2024-23649 is a high-severity Exposure of Sensitive Information to an Unauthorized Actor (CWE-200) vulnerability in Join-Lemmy Lemmy. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 40.7% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2024-0411
Vulnerability details
Lemmy is a link aggregator and forum for the fediverse. Starting in version 0.17.0 and prior to version 0.19.1, users can report private messages, even when they're neither sender nor recipient of the message. The API response to creating a…
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private message report contains the private message itself, which means any user can just iterate over message ids to (loudly) obtain all private messages of an instance. A user with instance admin privileges can also abuse this if the private message is removed from the response, as they're able to see the resulting reports. Creating a private message report by POSTing to `/api/v3/private_message/report` does not validate whether the reporter is the recipient of the message. lemmy-ui does not allow the sender to report the message; the API method should likely be restricted to accessible to recipients only. The API response when creating a report contains the `private_message_report_view` with all the details of the report, including the private message that has been reported: Any authenticated user can obtain arbitrary (untargeted) private message contents. Privileges required depend on the instance configuration; when registrations are enabled without application system, the privileges required are practically none. When registration applications are required, privileges required could be considered low, but this assessment heavily varies by instance. Version 0.19.1 contains a patch for this issue. A workaround is available. If an update to a fixed Lemmy version is not immediately possible, the API route can be blocked in the reverse proxy. This will prevent anyone from reporting private messages, but it will also prevent exploitation before the update has been applied.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Establishing permitted attributes and values, plus auditing changes, ensures authorization decisions are based on correctly managed policy data.
Requires explicit authorization for individuals to use external systems to access or handle organization-controlled information.
It mandates explicit checks to confirm the sharing partner's authorizations align with the information's access and use restrictions.
Review and removal of nonpublic information from publicly accessible systems directly prevents exposure of sensitive data to unauthorized actors.
Data mining protection mechanisms detect and block unauthorized bulk extraction of sensitive data, directly mitigating exposure to unauthorized actors.
Retaining and monitoring training records confirms personnel have completed privacy and security awareness training on handling sensitive data, reducing the chance of unauthorized exposure due to lack of knowledge.
Session auditing enables detection of unauthorized exposure or access to sensitive information during user activities.
Audit record review and analysis can detect unauthorized exposure or access to sensitive information.