[CVE-2020-17516] Apache Cassandra internode encryption enforcement vulnerability

[Aleksey Yeschenko <aleksey () apache org>]

CVE-2020-17516: Apache Cassandra doesn't enforce encryption setting on inbound internode connections

Severity:
Important

Vendor:
The Apache Software Foundation

Versions Affected:
Cassandra 2.1.0 to 2.1.22
Cassandra 2.2.0 to 2.2.19
Cassandra 3.0.0 to 3.0.23
Cassandra 3.11.0 to 3.11.9

Description:
When using ‘dc’ or ‘rack’ internode_encryption setting, a Cassandra instance allows both encrypted
and unencrypted connections. A misconfigured node or a malicious user can use the unencrypted
connection despite not being in the same rack or dc, and bypass mutual TLS requirement.

Mitigation:
Users of ALL versions should switch from ‘dc’ or ‘rack’ to ‘all’ internode_encryption setting, as they are inherently 
insecure
3.0.x users should additionally upgrade to 3.0.24
3.11.x users should additionally upgrade to 3.11.10

Credit:
This issue was discoverd by Jon Meredith