SV-205924r991589: Windows Server 2019 must preserve zone information when saving attachments. | Microsoft Windows Server 2019 STIG SCAP Benchmark

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Assessment Title

Rule Text

Windows Server 2019 must preserve zone information when saving attachments.

Description

Discussion Text

Attachments from outside sources may contain malicious code. Preserving zone of origin (Internet, intranet, local, restricted) information on file attachments allows Windows to determine risk.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000366SV-103399V-93311

References

DPMS Target Microsoft Windows Server 2019 DISA DPMS Target Microsoft Windows Server 2019 2907

Checks

DISA STIG (Manual Reference)

The default behavior is for Windows to mark file attachments with their zone information.

If the registry Value Name below does not exist, this is not a finding.

If it exists and is configured with a value of "2", this is not a finding.

If it exists and is configured with a value of "1", this is a finding.

Registry Hive: HKEY_CURRENT_USER
Registry Path: \SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Attachments\

Value Name: SaveZoneInformation

Value Type: REG_DWORD
Value: 0x00000002 (2) (or if the Value Name does not exist)

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.stig.windows2019:def:205924
# Windows Server 2019 must preserve zone information when saving attachments.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.
#
# MANUAL REVIEW REQUIRED -- the module(s) below could not be reconstructed
# into working code from curated SCC reference data, and are excluded from
# the automated result:
#   - ntuser_object (ntuser_test) -- 'Do not preserve zone information in file attachments' is set to 'Not Configured' or 'Disabled': no extractor for field "type"

# For the current user, 'Do not preserve zone information in file attachments' is set to 'Not Configured' or 'Disabled'
# registry_object (registry_test)
function test_2 {
  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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments').GetValueKind('SaveZoneInformation').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments' -Name 'SaveZoneInformation' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'SaveZoneInformation') -eq 2))
}

if (test_2) {
  Write-Output "PASS (automated portion only -- MANUAL REVIEW still required, see notes above)"
} else {
  Write-Output "FAIL (or see MANUAL REVIEW note above)"
}

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_server_2019 target this check assesses.

# OVAL Definition: oval:mil.disa.stig.windows2019:def:205924
if (!(Get-ItemProperty -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments" -ErrorAction SilentlyContinue).SaveZoneInformation -eq 2) { Write-Output "FAIL"; exit 1 } else { Write-Output "PASS"; exit 0 }

Remediation

The default behavior is for Windows to mark file attachments with their zone information.

If this needs to be corrected, configure the policy value for User Configuration >> Administrative Templates >> Windows Components >> Attachment Manager >> "Do not preserve zone information in file attachments" to "Not Configured" or "Disabled".