Microsoft-Windows-CAPI2 › Event 81

Event ID 81 — For more details for this event, please refer to the "Details" section

Provider
Microsoft-Windows-CAPI2
Channel
Operational
Level
Informational
Task
VerifyTrust
Opcode
Stop

Description

For more details for this event, please refer to the "Details" section.

Message #

For more details for this event, please refer to the "Details" section

Fields #

NameDescription
WinVerifyTrust.ActionID
WinVerifyTrust.UIChoice
WinVerifyTrust.RevocationCheck
WinVerifyTrust.StateAction
WinVerifyTrust.Flags
WinVerifyTrust.CatalogInfo
WinVerifyTrust.DigestInfo
WinVerifyTrust.RegPolicySetting
WinVerifyTrust.SignatureSettingsFlags
WinVerifyTrust.SignerInfo
WinVerifyTrust.CertificateChain
WinVerifyTrust.TimestampInfo
WinVerifyTrust.TimestampChain
WinVerifyTrust.EventAuxInfo
WinVerifyTrust.CorrelationAuxInfo
WinVerifyTrust.Result
EventWriteData UnicodeString

Example Event #

{
  "system": {
    "provider": "Microsoft-Windows-CAPI2",
    "guid": "{5bbca4a8-b209-48dc-a8c7-b23d3e5216fb}",
    "event_source_name": "",
    "event_id": 81,
    "version": 0,
    "level": 4,
    "task": 80,
    "opcode": 2,
    "keywords": 4611686018427387968,
    "time_created": "2026-03-13T20:00:05.310932+00:00",
    "event_record_id": 3570,
    "correlation": {},
    "execution": {
      "process_id": 3384,
      "thread_id": 2456
    },
    "channel": "Microsoft-Windows-CAPI2/Operational",
    "computer": "LAB-WIN11.ludus.domain",
    "security": {
      "user_id": "S-1-5-18"
    }
  },
  "user_data": {
    "WinVerifyTrust": {
      "ActionID": "{00AAC56B-CD44-11D0-8CC2-00C04FC295EE}",
      "UIChoice": {
        "value": "2",
        "Value": "WTD_UI_NONE"
      },
      "RevocationCheck": {
        "value": "1",
        "WTD_REVOKE_WHOLECHAIN": "true"
      },
      "StateAction": {
        "value": "1",
        "Value": "WTD_STATEACTION_VERIFY"
      },
      "Flags": {
        "value": "80001440",
        "WTD_REVOCATION_CHECK_CHAIN": "true",
        "WTD_USE_DEFAULT_OSVER_CHECK": "true",
        "WTD_CACHE_ONLY_URL_RETRIEVAL": "true",
        "CPD_USE_NT5_CHAIN_FLAG": "true"
      },
      "CatalogInfo": {
        "filePath": "C:\\Windows\\system32\\CatRoot\\{F750E6C3-38EE-11D1-85E5-00C04FC295EE}\\HyperV-UX-UI-merged-Package~31bf3856ad364e35~amd64~en-US~10.0.22621.1.cat",
        "Member": {
          "tag": "50663E8AAB49E7F04F52B4364ACE3B775A0696EF",
          "filePath": "C:\\Windows\\WinSxS\\msil_microsoft.virtualiz..on.client.resources_31bf3856ad364e35_10.0.22621.1_en-us_916cee91268b6c0a\\Microsoft.Virtualization.client.resources.dll",
          "hasFileHandle": "true",
          "hash": "50663E8AAB49E7F04F52B4364ACE3B775A0696EF",
          "hashFilePath": "\\Windows\\WinSxS\\msil_microsoft.virtualiz..on.client.resources_31bf3856ad364e35_10.0.22621.1_en-us_916cee91268b6c0a\\Microsoft.Virtualization.client.resources.dll"
        }
      },
      "DigestInfo": {
        "digestAlgorithm": "SHA1",
        "digest": "50663E8AAB49E7F04F52B4364ACE3B775A0696EF"
      },
      "RegPolicySetting": {
        "value": "23C00",
        "WTPF_OFFLINEOK_IND": "true",
        "WTPF_OFFLINEOK_COM": "true",
        "WTPF_OFFLINEOKNBU_IND": "true",
        "WTPF_OFFLINEOKNBU_COM": "true",
        "WTPF_IGNOREREVOCATIONONTS": "true"
      },
      "SignatureSettingsFlags": {
        "value": "20000000",
        "WSS_OUT_FILE_SUPPORTS_SEAL": "true"
      },
      "SignerInfo": {
        "DigestAlgorithm": {
          "oid": "2.16.840.1.101.3.4.2.1",
          "hashName": "SHA256"
        }
      },
      "CertificateChain": {
        "chainRef": "{422C2A8A-2D14-43B7-8F70-6DD1C807BC48}"
      },
      "TimestampInfo": {
        "format": "RFC 3161",
        "DigestAlgorithm": {
          "oid": "2.16.840.1.101.3.4.2.1",
          "hashName": "SHA256"
        },
        "SignTime": "2022-05-07T04:33:12.256Z"
      },
      "TimestampChain": {
        "chainRef": "{EB187775-EA45-4715-9648-CA7864F79031}"
      },
      "EventAuxInfo": {
        "ProcessName": "MsSense.exe"
      },
      "CorrelationAuxInfo": {
        "TaskId": "{116ED906-7813-42DD-902B-79FD5BF3FB24}",
        "SeqNumber": "11"
      },
      "Result": {
        "value": "0"
      }
    }
  },
  "message": ""
}

Detection Rules #

View all rules referencing this event →

Splunk # view in reference

  • Windows SIP WinVerifyTrust Failed Trust Validation source: The following analytic detects failed trust validation attempts using Windows Event Log - CAPI2 (CryptoAPI 2). It specifically triggers on EventID 81, which indicates that "The digital signature of the object did not verify." This detection leverages the CAPI2 Operational log to identify instances where digital signatures fail to validate. Monitoring this activity is crucial as it can indicate attempts to execute untrusted or potentially malicious binaries. If confirmed malicious, this activity could allow attackers to bypass security controls and execute unauthorized code, leading to potential system compromise.