TMA-IIS-7.3
Ensure SSLv3 is Disabled
Description
The SSLv3 protocol is not considered cryptographically secure, therefore should be disabled. SCHANNEL\Protocols\SSL 3.0\Server and \Client must both have Enabled=0 and DisabledByDefault=1. Affects every SCHANNEL service; a reboot is required after changes. PowerShell 5.1; reads the registry (run elevated).
How it is checked
Audit method: Windows registry
$base = 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols'; $bad = @('Server', 'Client' | Where-Object { $p = Get-ItemProperty -Path "$base\SSL 3.0\$_" -ErrorAction SilentlyContinue; $null -eq $p -or $p.Enabled -ne 0 -or $p.DisabledByDefault -ne 1 }); if ($bad.Count -eq 0) { 'compliant' } else { 'noncompliant' }- Expected output
compliant
How it is fixed
Fix method: Guidance or infrastructure patch
For both Server and Client: New-Item 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server' -Force | Out-Null; New-ItemProperty -Path <key> -Name Enabled -Value 0 -PropertyType DWord -Force; New-ItemProperty -Path <key> -Name DisabledByDefault -Value 1 -PropertyType DWord -Force; then reboot.
Properties
- Operating systems
- Any
- Tags
- iistls
- Reference
- CIS Microsoft IIS 10 Benchmark v1.2.1 - 7.3 Ensure SSLv3 is Disabled
Check this host
Run this on a machine you are allowed to audit. The scan is read-only.
tmaegis scan --target iis