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Authentication Bypass For Endpoints With Anonymous Access in Opencast

Critical severity GitHub Reviewed Published Jan 29, 2020 in opencast/opencast • Updated Jan 9, 2023

Package

maven org.opencastproject:opencast-kernel (Maven)

Affected versions

< 7.6
>= 8.0, < 8.1

Patched versions

7.6
8.1

Description

Impact

Using a remember-me cookie with an arbitrary username can cause Opencast to assume proper authentication for that user even if the remember-me cookie was incorrect given that the attacked endpoint also allows anonymous access.

This way, an attacker can, for example, fake a remember-me token, assume the identity of the global system administrator and request non-public content from the search service without ever providing any proper authentication.

Patches

This problem is fixed in Opencast 7.6 and Opencast 8.1

Workarounds

As a workaround for older, unpatched versions, disabling remember-me cookies in etc/security/mh_default_org.xml will mitigate the problem but will obviously also disable this feature without obvious indication. To deactivate this, remove the following line from the security configuration:

<sec:remember-me … />

References

For more information

If you have any questions or comments about this advisory:

References

@lkiesow lkiesow published to opencast/opencast Jan 29, 2020
Reviewed Jan 30, 2020
Published to the GitHub Advisory Database Jan 30, 2020
Last updated Jan 9, 2023

Severity

Critical

EPSS score

0.174%
(55th percentile)

Weaknesses

CVE ID

CVE-2020-5206

GHSA ID

GHSA-vmm6-w4cf-7f3x

Source code

No known source code
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