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HTTP Method Spoofing

High severity GitHub Reviewed Published Dec 14, 2021 in opencast/opencast • Updated Feb 1, 2023

Package

maven org.opencastproject:opencast-common (Maven)

Affected versions

< 9.10

Patched versions

9.10

Description

Opencast versions prior to 9.10 allow HTTP method spoofing, allowing to change the assumed HTTP method via URL parameter. This allows attackers to turn HTTP GET requests into PUT requests or an HTTP form to send DELETE requests. This bypasses restrictions otherwise put on these types of requests and aids in cross-site request forgery (CSRF) attacks, which would otherwise not be possible.

Impact

The vulnerability allows attackers to craft links or forms which may change the server state. For example, the following GET request would create a new user:

% curl -i -u admin:opencast \
  'https://legacy.opencast.org/admin-ng/users/test.json?_method=PUT&username=test&password=attack'
HTTP/2 200
…

If an admin is logged in to legacy.opencast.org and accidentally clicks this link, a user will silently be created.

Patches

This issue is fixed in Opencast 9.10 and 10.0.

Workarounds

You can mitigate the problem by setting the SameSite=Strict attribute for your cookies. If this is a viable option for you depends on your integrations. We strongly recommend updating in any case.

References

For more information

If you have any questions or comments about this advisory:

References

@lkiesow lkiesow published to opencast/opencast Dec 14, 2021
Published by the National Vulnerability Database Dec 14, 2021
Reviewed Dec 14, 2021
Published to the GitHub Advisory Database Dec 14, 2021
Last updated Feb 1, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS score

0.123%
(48th percentile)

Weaknesses

CVE ID

CVE-2021-43807

GHSA ID

GHSA-j4mm-7pj3-jf7v

Source code

Credits

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