TMA-IIS-4.7

Ensure Unlisted File Extensions are not allowed

보통레벨 1자동iis

설명

The FileExtensions Request Filter allows administrators to define specific extensions their web server(s) will allow and disallow. The property allowUnlisted will cover all other file extensions not explicitly allowed or denied. Often times, extensions such as .config, .bat, .exe, to name a few, should never be served. The AllowExtensions and DenyExtensions options are the UrlScan equivalents. requestFiltering fileExtensions allowUnlisted must be false at server level (then allow only required extensions). PowerShell 5.1 with the WebAdministration module; run elevated.

점검 방법

감사 방식: 셸 명령

shell

Import-Module WebAdministration -ErrorAction Stop; $c = Get-WebConfiguration -Filter 'system.webServer/security/requestFiltering/fileExtensions' -PSPath 'MACHINE/WEBROOT/APPHOST'; if ($c.allowUnlisted -eq $false) { 'compliant' } else { 'noncompliant' }

예상 출력: compliant

조치 방법

조치 방식: 가이드 또는 인프라 패치

Set-WebConfigurationProperty -PSPath 'MACHINE/WEBROOT/APPHOST' -Filter system.webServer/security/requestFiltering/fileExtensions -Name allowUnlisted -Value False (after adding <add fileExtension='.aspx' allowed='true'/> etc. for required types)

속성

운영 체제: 모두
태그: iisrequest-filtering
참고 자료: CIS Microsoft IIS 10 Benchmark v1.2.1 - 4.7 Ensure Unlisted File Extensions are not allowed

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shell

tmaegis scan --target iis