COM settings in OPC Classic client components: Difference between revisions

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[[Category:COM/DCOM]] [[Category:Troubleshooting]]
[[Category:COM/DCOM]] [[Category:Troubleshooting]]
This article describes the internal effects of the UseCustomSecurity, TurnOffCallSecurity and TurnOffActivationSecurity settings.
This article describes the internal effects of the UseCustomSecurity, TurnOffCallSecurity, TurnOffActivationSecurity and EnsureDataIntegrity settings.


'''COM and proxy initialization:'''
'''COM and proxy initialization:'''
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(see https://docs.microsoft.com/en-us/windows/win32/com/turning-off-activation-security?redirectedfrom=MSDN)
(see https://docs.microsoft.com/en-us/windows/win32/com/turning-off-activation-security?redirectedfrom=MSDN)


'''Common authentication level:''' RPC_C_AUTHN_LEVEL_CONNECT (2).
'''Common authentication level:''' In QuickOPC versions up to 2021.3: Always RPC_C_AUTHN_LEVEL_CONNECT (2). In QuickOPC versions 2022.1 and later:
* Without EnsureDataIntegrity (the default): RPC_C_AUTHN_LEVEL_CONNECT (2).
* With EnsureDataIntegrity: RPC_C_AUTHN_LEVEL_PKT_INTEGRITY (5). For [https://support.microsoft.com/en-us/topic/kb5004442-manage-changes-for-windows-dcom-server-security-feature-bypass-cve-2021-26414-f1400b52-c141-43d2-941e-37ed901c769c KB5004442—Manage changes for Windows DCOM Server Security Feature Bypass (CVE-2021-26414)].

Revision as of 18:07, 26 January 2022

This article describes the internal effects of the UseCustomSecurity, TurnOffCallSecurity, TurnOffActivationSecurity and EnsureDataIntegrity settings.

COM and proxy initialization:

  • Without UseCustomSecurity: CoInitializeSecurity is not called, CoSetProxyBlanket is not called
  • With UseCustomSecurity (the default): CoInitializeSecurity is called, CoSetProxyBlanket is called

CoInitializeSecurity parameters:

  • Without TurnOffCallSecurity (the default): dwAuthnLevel = Common authentication level (see below); dwImpLevel = RPC_C_IMP_LEVEL_IMPERSONATE (3); pSecDesc = CSecurityDescriptor::InitializeFromThreadToken()>
  • With TurnOffCallSecurity: dwAuthnLevel = RPC_C_AUTHN_LEVEL_NONE (1); dwImpLevel = RPC_C_IMP_LEVEL_IMPERSONATE (3); pSecDesc = NULL

CoSetProxyBlanket parameters: dwAuthnLevel and dwImpLevel are the same as those used with CoInitializeSecurity.

COAUTHINFO* pAuthInfo in COSERVERINFO* passed to CoCreateInstanceEx (when machine name is not empty):

  • Without TurnOffActivationSecurity (the default): dwAuthnSvc = RPC_C_AUTHN_NONE; dwAuthzSvc = RPC_C_AUTHZ_NONE; pwszServerPrincName = NULL; dwAuthnLevel = RPC_C_AUTHN_LEVEL_NONE; dwImpersonationLevel = RPC_C_IMP_LEVEL_IMPERSONATE; pAuthIdentityData = NULL; dwCapabilities = EOAC_NONE;
  • With TurnOffActivationSecurity: NULL

(see https://docs.microsoft.com/en-us/windows/win32/com/turning-off-activation-security?redirectedfrom=MSDN)

Common authentication level: In QuickOPC versions up to 2021.3: Always RPC_C_AUTHN_LEVEL_CONNECT (2). In QuickOPC versions 2022.1 and later:

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