Bug 1223319 (CVE-2024-31208) - VUL-0: CVE-2024-31208: matrix-synapse: weakness in auth chain indexing allows DoS
Summary: VUL-0: CVE-2024-31208: matrix-synapse: weakness in auth chain indexing allows...
Status: IN_PROGRESS
Alias: CVE-2024-31208
Product: openSUSE Distribution
Classification: openSUSE
Component: Security (show other bugs)
Version: Leap 15.5
Hardware: Other Other
: P3 - Medium : Normal (vote)
Target Milestone: ---
Assignee: Oliver Kurz
QA Contact: Security Team bot
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Reported: 2024-04-23 16:28 UTC by Alexander Bergmann
Modified: 2024-04-24 11:03 UTC (History)
1 user (show)

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Description Alexander Bergmann 2024-04-23 16:28:58 UTC
Weakness in auth chain indexing allows DoS from remote room members through disk fill and high CPU usage

Description
Impact

A remote Matrix user with malicious intent, sharing a room with Synapse instances before 1.105.1, can dispatch specially crafted events to exploit a weakness in how the auth chain cover index is calculated. This can induce high CPU consumption and accumulate excessive data in the database of such instances, resulting in a denial of service.

Servers in private federations, or those that do not federate, are not affected.
Patches

Server administrators should upgrade to 1.105.1 or later.
Workarounds

One can:

    ban the malicious users or ACL block servers from the rooms; and/or
    leave the room and purge the room using the admin API

For more information

If you have any questions or comments about this advisory, please email us at security AT element.io.

References:
https://github.com/element-hq/synapse/security/advisories/GHSA-3h7q-rfh9-xm4v
https://github.com/element-hq/synapse/releases/tag/v1.105.1
Comment 1 OBSbugzilla Bot 2024-04-23 17:15:09 UTC
This is an autogenerated message for OBS integration:
This bug (1223319) was mentioned in
https://build.opensuse.org/request/show/1169911 Factory / matrix-synapse
Comment 2 Oliver Kurz 2024-04-24 11:03:44 UTC
https://build.opensuse.org/request/show/1169911
Open review for openSUSE:Factory:Staging:adi:89