Title

Firefox deprecated ciphers must be disabled. (Cat II impact)

Discussion

A weak cipher is defined as an encryption/decryption algorithm that uses a key of insufficient length. Using an insufficient length for a key in an encryption/decryption algorithm opens up the possibility (or probability) that the encryption scheme could be broken.

Check Content

Type "about:policies" in the browser address bar. If "DisabledCiphers" is not displayed under Policy Name or the Policy Value is not "TLS_RSA_WITH_3DES_EDE_CBC_SHA" with a value of "true", this is a finding.

Fix Text

Windows group policy: 1. Open the group policy editor tool with "gpedit.msc". 2. Navigate to Policy Path: Computer Configuration\Administrative Templates\Mozilla\Firefox\Disabled Ciphers Policy Name: TLS_RSA_WITH_3DES_EDE_CBC_SHA Policy State: Enabled macOS "plist" file: Add the following: <key>DisabledCiphers</key> <dict> <key>TLS_RSA_WITH_3DES_EDE_CBC_SHA</key> <true/> </dict> Linux "policies.json" file: Add the following in the policies section: "DisabledCiphers": { "TLS_RSA_WITH_3DES_EDE_CBC_SHA": true }

Additional Identifiers

Rule ID: SV-251571r879587_rule

Vulnerability ID: V-251571

Group Title: SRG-APP-000141

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.