SV-225482r852254: The system must be configured to limit how often keep-alive packets are sent. | Microsoft Windows Server 2012/2012 R2 Member Server STIG SCAP Benchmark

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Assessment Title

Rule Text

The system must be configured to limit how often keep-alive packets are sent.

Description

Discussion Text

This setting controls how often TCP sends a keep-alive packet in attempting to verify that an idle connection is still intact. A higher value could allow an attacker to cause a denial of service with numerous connections.

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-002385CCE-24310-5SV-52927V-4113

References

DPMS Target Microsoft Windows Server 2012-2012 R2 MS DISA DPMS Target Microsoft Windows Server 2012-2012 R2 MS 4214

Checks

OVAL

oval:mil.disa.fso.windows:var:456900 ← xccdf_mil.disa.stig_value_keep_alive_time_var

DISA STIG (Manual Reference)

If the following registry value does not exist or is not configured as specified, this is a finding:

Registry Hive: HKEY_LOCAL_MACHINE 
Registry Path: \System\CurrentControlSet\Services\Tcpip\Parameters\

Value Name: KeepAliveTime

Value Type: REG_DWORD
Value: 300000 (or less)

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

# Windows PowerShell
# Reconstructed from oval:mil.disa.fso.windows:def:4569
# The system must be configured to limit how often keep-alive packets are sent.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# Verifies 'MSS: (KeepAliveTime) How often keep-alive packets are sent in milliseconds' is set to '300000 or 5 minutes (recommended)' or less
# registry_object (registry_test)
function test_1 {
  return (((@{String='reg_sz';ExpandString='reg_expand_sz';Binary='reg_binary';DWord='reg_dword';MultiString='reg_multi_sz';QWord='reg_qword';None='reg_none'}[(Get-Item -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters').GetValueKind('KeepAliveTime').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters' -Name 'KeepAliveTime' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'KeepAliveTime') -le 300000))
}

if (test_1) {
  Write-Output "PASS"
} else {
  Write-Output "FAIL"
}

Assessment Script Powered by AISyntax-verified

A standalone PowerShell script to assess this control automatically. Review before running it in your environment.

Syntax-checked as valid PowerShell. Not executed here — running it for real needs the actual ms_windows_2012_and_2012_r2_ms target this check assesses.

#
# This script implements the OVAL definition: oval:mil.disa.fso.windows:def:4569
$registryPath = "HKLM:\System\CurrentControlSet\Services\Tcpip\Parameters"
$registryKey = "KeepAliveTime"
if(Test-Path $registryPath){
    $registryValue = (Get-ItemProperty -Path $registryPath -Name $registryKey -ErrorAction SilentlyContinue).$registryKey
    if($registryValue -eq $null -or [int]$registryValue -le 300000){
        Write-Output "PASS"; exit 0
    }
}
Write-Output "FAIL"; exit 1

Remediation

Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options -> "MSS: (KeepAliveTime) How often keep-alive packets are sent in milliseconds" to "300000 or 5 minutes (recommended)" or less.

(See "Updating the Windows Security Options File" in the STIG Overview document if MSS settings are not visible in the system's policy tools.)