Client Encryption
Scanned 5/30/2026
Install via CLI
openskills install CyberStrikeus/CyberStrike---
name: cis-cassandra40-v110-5.2
description: "Client Encryption"
category: cis-cassandra
version: "1.1.0"
author: cyberstrike-official
tags: [cis, cassandra, encryption, tls, ssl, client]
cis_id: "5.2"
cis_benchmark: "CIS Apache Cassandra 4.0 Benchmark v1.1.0"
tech_stack: [cassandra]
cwe_ids: []
chains_with: []
prerequisites: []
severity_boost: {}
---
# 5.2 Client Encryption
## Profile Applicability
- Level 1 - Cassandra on Linux
## Description
Cassandra offers the option to encrypt data in transit between the client and nodes on the cluster. By default client encryption is turned off.
## Rationale
Data in transit between the client and node on the cluster should be encrypted to avoid network snooping, whether legitimate or not.
## Audit
The Cassandra configuration files can be found in the conf directory of tarballs. For packages, the configuration files will be located in `/etc/cassandra`.
Open up the `cassandra.yaml` file, look for `client_encryption_options` section.
Look for `enabled:` and `optional:`:
```yaml
enabled: true
optional: false
```
If neither is true, then all client connections are unencrypted which makes this a finding.
If enabled is true and optional is false, then all client connections must be encrypted which makes this not a finding.
If enabled is false and optional is true, then enabled wins and all client connections are unencrypted which makes this a finding.
If both are set to true, then both unencrypted and encrypted connections are allowed on the same port which makes this not a finding.
## Remediation
The client encryption should be implemented before anyone accesses the Cassandra server.
To enable the client encryption mechanism:
1. Stop the Cassandra database.
2. If not done so already, build out your keystore and truststore.
3. Modify `cassandra.yaml` file to modify/add entries under `client_encryption_options`:
```yaml
set enabled: true
set optional: false
```
This will force all connections to be encrypted between client and node on the cluster.
4. Start the Cassandra database.
## Default Value
```yaml
enabled: false
optional: false
```
## References
1. http://cassandra.apache.org/doc/latest/operating/security.html
## CIS Controls
**v8:**
- 3.10 Encrypt Sensitive Data in Transit - Encrypt sensitive data in transit. Example implementations can include: Transport Layer Security (TLS) and Open Secure Shell (OpenSSH).
**v7:**
- 14.4 Encrypt All Sensitive Information in Transit - Encrypt all sensitive information in transit.
## Profile
- Level 1 | Automated
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