# Cis Cassandra41 5.2

> Client Encryption

- Skill: `cyberstrikeus/cis-cassandra41-5-2` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-cassandra41-5-2`
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- Category: Coding & Dev Tools
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/cis-cassandra41-5-2

---


# 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
client_encryption_options:
  enabled: true
  optional: false
  keystore: /path/to/keystore
  keystore_password: <password>
  require_client_auth: false
  truststore: /path/to/truststore
  truststore_password: <password>
  protocol: TLS
  algorithm: SunX509
  store_type: JKS
  cipher_suites: [TLS_RSA_WITH_AES_128_CBC_SHA, TLS_RSA_WITH_AES_256_CBC_SHA]
```

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