SV-83443r1: Structured Exception Handling Overwrite Protection (SEHOP) must be turned on. | Windows 7 Security Technical Implementation Guide

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Assessment Title

Rule Text

Structured Exception Handling Overwrite Protection (SEHOP) must be turned on.

Description

Discussion Text

Attackers are constantly looking for vulnerabilities in systems and applications. Structured Exception Handling Overwrite Protection (SEHOP) blocks exploits that use the Structured Exception Handling overwrite technique, a common buffer overflow attack.

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

IA Controls

NIST SP 800-53

Not mappedCCI-002824

References

DPMS Target Windows 7 DISA DPMS Target Windows 7 1712

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:5152
# Structured Exception Handling Overwrite Protection (SEHOP) must be turned on.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# Verifies SEHOP is on and configured correctly
# 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\Control\Session Manager\kernel').GetValueKind('DisableExceptionChainValidation').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\kernel' -Name 'DisableExceptionChainValidation' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'DisableExceptionChainValidation') -eq 0))
}
# Verifies EMET is installed
# registry_object (registry_test)
function test_2 {
  return (($null -ne (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\Products' -Name 'Comments')) -or ($null -ne (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\Products' -Name 'Comments')))
}
# Verifies EMET 5.5 or higher is installed
# registry_object (registry_test)
function test_3 {
  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\').GetValueKind('DisplayVersion').ToString()]) -eq 'reg_sz') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\' -Name 'DisplayVersion' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'DisplayVersion') -ge '5.5'))
}
# Verifies 'System SEHOP' is set to 'Enabled' with 'Application Opt Out' selected
# registry_object (registry_test)
function test_4 {
  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\Software\Policies\Microsoft\EMET\SysSettings').GetValueKind('SEHOP').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\EMET\SysSettings' -Name 'SEHOP' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'SEHOP') -eq 2))
}

if ((test_1 -or (test_2 -and test_3 -and test_4))) {
  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 windows_7 target this check assesses.

# OVAL Definition: oval:mil.disa.fso.windows:def:5152
if (!(Test-Path -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\kernel\DisableExceptionChainValidation" -ErrorAction SilentlyContinue) -or ((Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\kernel\DisableExceptionChainValidation" -ErrorAction SilentlyContinue).DisableExceptionChainValidation -ne 0)) {Write-Output "FAIL"; Exit 1} else {Write-Output "PASS"; Exit 0}

Remediation

Configure the following registry value:

				Registry Hive: HKEY_LOCAL_MACHINE
				Registry Path: \SYSTEM\CurrentControlSet\Control\Session Manager\kernel\

				Value Name: DisableExceptionChainValidation

				Value Type: REG_DWORD
				Value: 0