Description

Graylog is a free and open log management platform. Starting in version 4.3.0 and prior to versions 5.1.11 and 5.2.4, reauthenticating with an existing session cookie would re-use that session id, even if for different user credentials. In this case, the pre-existing session could be used to gain elevated access to an existing Graylog login session, provided the malicious user could successfully inject their session cookie into someone else's browser. The complexity of such an attack is high, because it requires presenting a spoofed login screen and injection of a session cookie into an existing browser, potentially through a cross-site scripting attack. No such attack has been discovered. Graylog 5.1.11 and 5.2.4, and any versions of the 6.0 development branch, contain patches to not re-use sessions under any circumstances. Some workarounds are available. Using short session expiration and explicit log outs of unused sessions can help limiting the attack vector. Unpatched this vulnerability exists, but is relatively hard to exploit. A proxy could be leveraged to clear the `authentication` cookie for the Graylog server URL for the `/api/system/sessions` endpoint, as that is the only one vulnerable.

Weaknesses 1

Affected Products 2

References 3

• github.com https://github.com/Graylog2/graylog2-server/commit/1596b749db86368ba476662f23a0f0c5ec2b5097
  Patch
• github.com https://github.com/Graylog2/graylog2-server/commit/b93a66353f35a94a4e8f3f75ac4f5cdc5a2d4a6a
  Patch
• github.com https://github.com/Graylog2/graylog2-server/security/advisories/GHSA-3xf8-g8gr-g7rh
  Vendor Advisory

Remediation

• github.com https://github.com/Graylog2/graylog2-server/commit/1596b749db86368ba476662f23a0f0c5ec2b5097
  Patch
• github.com https://github.com/Graylog2/graylog2-server/commit/b93a66353f35a94a4e8f3f75ac4f5cdc5a2d4a6a
  Patch