SV-25169r2: The system must be configured to prevent unsolicited remote assistance offers. | Windows 7 Security Technical Implementation Guide

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Assessment Title

Rule Text

The system must be configured to prevent unsolicited remote assistance offers.

Description

Discussion Text

Remote assistance allows another user to view or take control of the local session of a user. Unsolicited remote assistance is help that is offered by the remote user. This may allow unauthorized parties access to the resources on the computer.

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

IA Controls

NIST SP 800-53

Not mappedCCI-001090CCE-9960-6

Additional Details

Mitigations

3.082 Win 7

Third-Party Tools

Mitigation Control

-Users must be trained to include the following: -Users must know who they can accept a remote assistance offer from. The remote assistance offer must be in response to a help desk request or confirmed with the help desk if an unsolicited remote assistance offer comes through. -Users must know how to accept a request, allow view or control, and disconnect a remote assistance session. -Users must monitor the remote assistance activity at the workstation while it is occurring. -The support personnel allowed to offer remote assistance (helpers) must be limited and documented. -Port 3389 must be blocked at the perimeter to prevent other access. Accounts and groups authorized to offer remote assistance (helpers) are identified in the following registry key. Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services\ RAUnsolicit\ Each account or group will be listed under a separate value name with the value equaling the value name as in the following examples: Value Name: Administrators Value Type: REG_SZ Value: Administrators Value Name: TestUser Value Type: REG_SZ Value: TestUser

Responsibility

System Administrator

References

DPMS Target Windows 7 DISA DPMS Target Windows 7 1712

Checks

OVAL

oval:mil.disa.fso.windows:var:381800 ← xccdf_mil.disa.stig_value_offer_remote_assistance_var

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:3818
# The system must be configured to prevent unsolicited remote assistance offers.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# Verifies 'Configure Offer Remote Assistance' is set to 'Disabled'
# 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\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services').GetValueKind('fAllowUnsolicited').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services' -Name 'fAllowUnsolicited' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'fAllowUnsolicited') -eq 0))
}

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 windows_7 target this check assesses.

# OVAL Definition: oval:mil.disa.fso.windows:def:3818
$regPath = "HKLM:\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services"
$regKey = "fAllowUnsolicited"
$regValue = 0

if (-not (Test-Path $regPath)) { exit 0 }
if (-not (Get-ItemProperty -Path $regPath -Name $regKey -ErrorAction SilentlyContinue).$regKey -eq $regValue) { exit 1 }
exit 0

Remediation

Configure the system to prevent unsolicited remote assistance offers by setting the policy value for Computer Configuration >> Administrative Templates >> System >> Remote Assistance >> "Offer Remote Assistance" to "Disabled".