S2S TcpToken authentication bypass
Advisory ID: SVD-2022-0503
CVSSv3.1 Score: 7.5, High
CVE ID: CVE-2021-31559
Last Update: 2022-05-03
CVSSv3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
A crafted request bypasses S2S TCP Token authentication writing arbitrary events to an index in Splunk Enterprise Indexer 8.1 versions before 8.1.5 and 8.2 versions before 8.2.1. The vulnerability impacts Indexers configured to use TCPTokens. It does not impact Universal Forwarders.
When Splunk forwarding is secured using TLS, the attack requires compromising the certificate. As a partial mitigation and a security best practice, see Configure Splunk forwarding to use your own SSL certificates. Implementation reduces the severity to Medium.
Upgrade Splunk Enterprise Indexer 8.1 versions to 8.1.5 or later and 8.2.0 versions to 8.2.1 or later.
|Product||Version||Affected Versions||Fix Version|
|Splunk Enterprise||8.1||8.1.4 and earlier||8.1.5|
The vulnerability does not impact Splunk Cloud Platform instances.