GitHub Advisoryadvisory · Maven
GHSA-59g4-hpg3-3gcp Files Accessible to External Parties in Opencast
CRITICAL
Official page ↗
- Aliases
- CVE-2021-43821
- Ecosystem
- Maven
- Packages
- org.opencastproject:opencast-ingest-service-impl
- Severity
- Critical
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Weaknesses
- CWE-552
- Reviewed
- 2021-12-14
Affected packages
• Maven org.opencastproject:opencast-ingest-service-impl: < 10.6 → fixed in 10.6
Description
Opencast before version 10.6 allows references to local file URLs in ingested media packages, allowing attackers to include local files from Opencast's host machines and making them available via the web interface.
Impact
Before Opencast 10.6, Opencast would open and include local files during ingests. Attackers could exploit this to include most local files the process has read access to, extracting secrets from the host machine.
For example, to expose the `custom.properties` of develop.opencast.org via the asset manager, an attacker could have run:
```
curl -f -i -u admin:opencast \
https://develop.opencast.org/ingest/addMediaPackage/fast \
-F 'flavor=presenter/source'\
-F mediaUri=file:///srv/opencast/opencast-dist-allinone/etc/custom.properties\
-F title="custom.properties"
```
An attacker would need to have the privileges required to add new media to exploit this. But these are often widely given.
Patches
The issue has been fixed in Opencast 10.6 and 11.0.
Workarounds
You can mitigate this issue by narrowing down the read access Opencast has to files on the file system using UNIX permissions or mandatory access control systems like SELinux. This cannot prevent access to files Opencast needs to read though and we highly recommend updating.
References
• Example of problematic code.
• Patch fixing the issue
For more information
If you have any questions or comments about this advisory:
• Open an issue in our issue tracker
• Email us at [email protected]
Related
Alias · CVE (1)
- CVE-2021-43821 Opencast is an Open Source Lecture Capture & Video Management for Education. vulnerability
Weakness · CWE (1)
- CWE-552 Files or Directories Accessible to External Parties weakness
References
- https://github.com/opencast/opencast/security/advisories/GHSA-59g4-hpg3-3gcp web
- https://nvd.nist.gov/vuln/detail/CVE-2021-43821 advisory
- https://github.com/opencast/opencast/commit/65c46b9d3e8f045c544881059923134571897764 web
- https://github.com/opencast/opencast package
- https://github.com/opencast/opencast/blob/69952463971cf578363e3b97d8edaf334ff51253/modules/ingest-service-impl/src/main/java/org/opencastproject/ingest/impl/IngestServiceImpl.java#L1587 web
- https://mvnrepository.com/artifact/org.opencastproject/opencast-ingest-service-impl web