Etherpad is a real-time collaborative editor. In versions prior to 1.8.16, an attacker can craft an `*.etherpad` file that, when imported, might allow the attacker to gain admin privileges for the Etherpad instance. This, in turn, can be used to install a malicious Etherpad plugin that can execute arbitrary code (including system commands). To gain privileges, the attacker must be able to trigger deletion of `express-session` state or wait for old `express-session` state to be cleaned up. Core Etherpad does not delete any `express-session` state, so the only known attacks require either a plugin that can delete session state or a custom cleanup process (such as a cron job that deletes old `sessionstorage:*` records). The problem has been fixed in version 1.8.16. If users cannot upgrade to 1.8.16 or install patches manually, several workarounds are available. Users may configure their reverse proxies to reject requests to `/p/*/import`, which will block all imports, not just `*.etherpad` imports; limit all users to read-only access; and/or prevent the reuse of `express_sid` cookie values that refer to deleted express-session state. More detailed information and general mitigation strategies may be found in the GitHub Security Advisory.
References
Link | Resource |
---|---|
https://github.com/ether/etherpad-lite/compare/b7065eb9a0ec7c3c265f8cfeb2534efe6f036456...77bcb507b30e762e9375b0511b3763e0162aae53 | Patch Third Party Advisory |
https://github.com/ether/etherpad-lite/issues/5010 | Issue Tracking Third Party Advisory |
https://github.com/ether/etherpad-lite/releases/tag/1.8.16 | Release Notes Third Party Advisory |
https://github.com/ether/etherpad-lite/security/advisories/GHSA-w3g3-qf3g-2mqc | Mitigation Patch Third Party Advisory |
History
No history.
MITRE Information
Status: PUBLISHED
Assigner: GitHub_M
Published: 2021-12-09T22:35:12
Updated: 2021-12-09T22:35:12
Reserved: 2021-11-16T00:00:00
Link: CVE-2021-43802
JSON object: View
NVD Information
Status : Analyzed
Published: 2021-12-09T23:15:07.517
Modified: 2023-08-31T16:19:33.527
Link: CVE-2021-43802
JSON object: View
Redhat Information
No data.