An IIS 10.0 web server must maintain the confidentiality of controlled information during transmission through the use of an approved Transport Layer Security (TLS) version.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
high	V-218821	SRG-APP-000439-WSR-000156	IIST-SV-000153	SV-218821r1067596_rule	2025-02-11	3

Description
TLS encryption is a required security setting for a private web server. Encryption of private information is essential to ensuring data confidentiality. If private information is not encrypted, it can be intercepted and easily read by an unauthorized party. A private web server must use a FIPS 140-2-approved TLS version, and all non-FIPS-approved SSL versions must be disabled. NIST SP 800-52 specifies the preferred configurations for government systems.

Description

TLS encryption is a required security setting for a private web server. Encryption of private information is essential to ensuring data confidentiality. If private information is not encrypted, it can be intercepted and easily read by an unauthorized party. A private web server must use a FIPS 140-2-approved TLS version, and all non-FIPS-approved SSL versions must be disabled. NIST SP 800-52 specifies the preferred configurations for government systems.

ℹ️ Check
Access the IIS 10.0 Web Server. Navigate to: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server Verify a REG_DWORD value of "0" for "DisabledByDefault". Verify a REG_DWORD value of "1" for "Enabled". Navigate to: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server Verify a REG_DWORD value of "1" for "DisabledByDefault". Verify a REG_DWORD value of "0" for "Enabled". If any of the respective registry paths do not exist or are configured with the wrong value, this is a finding. SSL 3.0 is disabled by default in newer Operating Systems. If SSL 3.0 has a registry DWORD enabled with a value of 1, this is a finding. If this key is not present, this is not a finding.

ℹ️ Check

Access the IIS 10.0 Web Server. Navigate to: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server Verify a REG_DWORD value of "0" for "DisabledByDefault". Verify a REG_DWORD value of "1" for "Enabled". Navigate to: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server Verify a REG_DWORD value of "1" for "DisabledByDefault". Verify a REG_DWORD value of "0" for "Enabled". If any of the respective registry paths do not exist or are configured with the wrong value, this is a finding. SSL 3.0 is disabled by default in newer Operating Systems. If SSL 3.0 has a registry DWORD enabled with a value of 1, this is a finding. If this key is not present, this is not a finding.

✔️ Fix
Access the IIS 10.0 Web Server. Navigate to: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server Create a REG_DWORD named "DisabledByDefault" with a value of "0". Create a REG_DWORD named "Enabled" with a value of "1". Navigate to: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server For each protocol: Create a REG_DWORD named "DisabledByDefault" with a value of "1". Create a REG_DWORD named "Enabled" with a value of "0".

✔️ Fix

Access the IIS 10.0 Web Server. Navigate to: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server Create a REG_DWORD named "DisabledByDefault" with a value of "0". Create a REG_DWORD named "Enabled" with a value of "1". Navigate to: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server For each protocol: Create a REG_DWORD named "DisabledByDefault" with a value of "1". Create a REG_DWORD named "Enabled" with a value of "0".