STIGQter: STIG Summary: Mozilla Firefox Security Technical Implementation Guide Version: 6 Release: 8 Benchmark Date: 01 Jul 2026:

Firefox deprecated ciphers must be disabled.

DISA Rule

SV-251571r960963_rule

Vulnerability Number

V-251571

Group Title

SRG-APP-000141

Rule Version

FFOX-00-000027

Severity

CAT II

CCI(s)

• CCI-000381 - Configure the system to provide only organization-defined mission essential capabilities.

Weight

10

Fix Recommendation

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
}

Check Contents

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.

Vulnerability Number

V-251571

Documentable

False

Rule Version

FFOX-00-000027

Severity Override Guidance

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.

Check Content Reference

M

Target Key

5446