Ecosyste.ms: Advisories
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Security Advisories: GSA_kwCzR0hTQS1oNzdmLXh4eDctNDg1OM0VmQ
User impersonation due to incorrect handling of the login JWT
Impact
This allows anyone that can connect to the server to forge a LoginPacket with manipulated JWT token allowing impersonation as any Bedrock user. Unless credentials are saved in your configuration, online mode is not affected as users are still required to log in separately. If your credentials are saved, there is no risk of exposing your email or password.
Patches
This was patched as part of https://github.com/GeyserMC/Geyser/commit/b9541505af68ac7b7c093206ac7b1ba88957a5a6 and https://github.com/GeyserMC/Geyser/commit/ab2f5b326fe590e09167e8b45b4b165ac06ecd13. if your Geyser version is 1.4.2-SNAPSHOT
or later, the issue has been addressed on your build.
Workarounds
Geyser strongly recommends updating to fix this issue. If this isn't possible:
- Use online mode and don't save credentials in your Geyser configuration
- Use an additional authentication method on the Java server
References
This was disclosed to us by a staff member over at Hive; you can read their disclosure here: https://updates.playhive.com/weekend-maintenance-disclosure-2kJMaY
For more information
If you have any questions or comments about this advisory:
- Come talk to us over on our Discord server in the #development channel
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS1oNzdmLXh4eDctNDg1OM0VmQ
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: over 2 years ago
Updated: about 1 year ago
CVSS Score: 7.4
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Identifiers: GHSA-h77f-xxx7-4858, CVE-2021-39177
References:
- https://github.com/GeyserMC/Geyser/security/advisories/GHSA-h77f-xxx7-4858
- https://nvd.nist.gov/vuln/detail/CVE-2021-39177
- https://github.com/GeyserMC/Geyser/commit/b9541505af68ac7b7c093206ac7b1ba88957a5a6
- https://updates.playhive.com/weekend-maintenance-disclosure-2kJMaY
- https://github.com/advisories/GHSA-h77f-xxx7-4858
Blast Radius: 1.0
Affected Packages
maven:org.geysermc:connector
Affected Version Ranges: <= 1.4.1-SNAPSHOTFixed in: 1.4.2-SNAPSHOT