Privilege Escalation Affecting ep_etherpad-lite package, versions *
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Test your applications- Snyk ID SNYK-JS-EPETHERPADLITE-2314881
- published 10 Dec 2021
- disclosed 10 Dec 2021
- credit Unknown
Introduced: 10 Dec 2021
CVE-2021-43802 Open this link in a new tabHow to fix?
A fix was pushed into the master branch but not yet published.
Overview
ep_etherpad-lite is a modern really-real-time collaborative document editor.
Affected versions of this package are vulnerable to Privilege Escalation. 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).
If users cannot upgrade to the fixed version 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.