8a162702-b043-4108-bb6c-1488751a4a32

dkrTK.sys :inline :inline

Description

The User Agent tjr.exe, which is protected via a virtual machine, drops the kernel driver to the user temporary directory C:%User%\AppData\Local\Temp\Ktgn.sys. It then installs the dropped driver with the name ktgn and the start value = System (to start when the system restarts). From our analysis of what occurs when a user interfaces with this driver, we observed that it only uses one of the exposed Device Input and Output Control (IOCTL) code — Kill Process, which is used to kill security agent processes installed on the system.

  • UUID: 8a162702-b043-4108-bb6c-1488751a4a32
  • Created: 2023-05-22
  • Author: Will BushidoToken
  • Acknowledgement: BushidoToken | BushidoToken

DownloadBlock

This download link contains the malicious driver!

Commands

sc.exe create dkrTK.sys binPath=C:\windows\temp\dkrTK.sys type=kernel && sc.exe start dkrTK.sys
Use CasePrivilegesOperating System
Elevate privilegeskernelWindows 10

Detections

YARA 🏹

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Exact Match

with header and size limitation

Threat Hunting

without header and size limitation

Sigma 🛡️

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Names

detects loading using name only

Hashes

detects loading using hashes only

Sysmon 🔎

Expand

Block

on hashes

Alert

on hashes

Resources


  • https://www.trendmicro.com/content/dam/trendmicro/global/en/research/23/e/blackcat-ransomware-deploys-new-signed-kernel-driver/indicators-blackcat-ransomware-deploys-new-signed-kernel-driver.txt
  • https://www.trendmicro.com/en_us/research/23/e/blackcat-ransomware-deploys-new-signed-kernel-driver.html

    • Known Vulnerable Samples

    PropertyValue
    FilenamedkrTK.sys
    Creation Timestamp2022-06-02 04:09:08
    MD5a837302307dace2a00d07202b661bce2
    SHA191568d7a82cc7677f6b13f11bea5c40cf12d281b
    SHA25652d5c35325ce701516f8b04380c9fbdb78ec6bcc13b444f758fdb03d545b0677
    Authentihash MD5233c2815720d7aa90838780dc482ddb9
    Authentihash SHA16271a84b349debb9a1bf7a5a164e91ef6cb9f869
    Authentihash SHA25624395b622d4fd48864a50978ffd2b82fdded5189741a6deea9293cc075cd0c6b
    RichPEHeaderHash MD5ffdf660eb1ebf020a1d0a55a90712dfb
    RichPEHeaderHash SHA13e905e3d061d0d59de61fcf39c994fcb0ec1bab3
    RichPEHeaderHash SHA2562b3f99a94b7a7132854be769e27b331419c53989ef42f686d6f5ba09ddefefd6

    Download

    Certificates

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    Certificate 38de06b8be15187f107e04f8b1138977
    FieldValue
    ToBeSigned (TBS) MD51e71dd41570c4bb591861555853106a3
    ToBeSigned (TBS) SHA11cb57dd770235af6c117b995e9c52909a0e44684
    ToBeSigned (TBS) SHA2564ebff6116837c32889b3bcbabd82137e69a7d30ea1458d8e8e9a1861379761f3
    SubjectC=CN, ST=Shandong, L=Zaozhuang, O=Bopsoft, CN=Bopsoft
    ValidFrom2018-03-02 00:00:00
    ValidTo2018-11-28 23:59:59
    Signature261c8eec3489c246498e8f65d4f68bd4f1e569760f9653601c877ad5f755bdd0ff729e81ced79aa051ea3ad404a74ba13cfeba87cc44b1960463280c5e44162713038f4d63e5737afe06427b934e403eb31fe76ae672575dc7fc72dd9fb199680d9fc4a8dcb31662b45423e6e738418066d9e14968a0d3e85c3c8e820692d6bcc203e675079a773681d8ddb91b81a808c2f1be43fba6343d82403ea067bbc6a3fe28a67de9a82707dfbbd8e1e06e977676242b32467bd02351843eefe183b603c04af960d6777e2958b7d88d6512190b3af858188be9e9bc3cd1e2fe92adbec1bca5885ab6d021a048f258b55a0ff5b7d55d94db1694840771f54b63862a9cd2
    SignatureAlgorithmOID1.2.840.113549.1.1.5
    IsCertificateAuthorityFalse
    SerialNumber38de06b8be15187f107e04f8b1138977
    Version3
    Certificate 47974d7873a5bcab0d2fb370192fce5e
    FieldValue
    ToBeSigned (TBS) MD5e3a93dc2a8a8a668fdbb286bfe9afab5
    ToBeSigned (TBS) SHA195795d2aa2a554a423bc8c6e5b0a016d14887d35
    ToBeSigned (TBS) SHA256d8844186775bddbccaf3dc017064df7d760fd4b85c5d07561a3efd7da950f89e
    SubjectC=US, O=Thawte, Inc., CN=Thawte Code Signing CA , G2
    ValidFrom2010-02-08 00:00:00
    ValidTo2020-02-07 23:59:59
    Signature56fe535ce1c79ebca7ed7e536d6a144b518c405e805faaa4e82fef38c804c9ca3ecfdf3a584eb0d4b663c52957fa02059a454d68db2a1bd4343d9f00c35acb9549a56ee1b0c5fc414d414a6fd377c8d7388de419de18f31f1565836d450c53f90a9a2ea55dbf6f32811892196a5500ad631c52067e55d92968ae4a7c189a79886b2323d827382a298776cafbc7b662231fed7a564cdd9c325bf53d0c4618953b2a2368836441d9006d0f1924156872bdc571676eac4cdb90eb51a51a6207d0be6a00473c722fec4f613e7385ce5a0ab7bac01c1375e3223928dd6d1d09469d4fbae8408191c6a4ce94721b01cf2a6e15679589ae7db7b7cdf90a3d75b66b3c25
    SignatureAlgorithmOID1.2.840.113549.1.1.5
    IsCertificateAuthorityTrue
    SerialNumber47974d7873a5bcab0d2fb370192fce5e
    Version3
    Certificate 611fb0a400000000001d
    FieldValue
    ToBeSigned (TBS) MD5a3f222107d4e1085e73b5b589c2f480b
    ToBeSigned (TBS) SHA1b94aa26cd77c48d91a53ac44506cbd255e1d362c
    ToBeSigned (TBS) SHA256a39ed0d6fd4eb1a6f7fed60f726e23eae668b7591bc004644625d22c701213fa
    SubjectC=US, O=thawte, Inc., OU=Certification Services Division, OU=(c) 2006 thawte, Inc. , For authorized use only, CN=thawte Primary Root CA
    ValidFrom2011-02-22 19:31:57
    ValidTo2021-02-22 19:41:57
    Signature2dcc71b5e8ba94ff5ee64467007b6afc412c3ee70e41855ab12a932ba95b89f2f72b499c8003f297b8e760a80ed7fd5de545467594f4ed1c9de166228b61fb29f2c6a8bdf387c98f7f47e1c058b64a1aa2e7f718606969e083069e26c775c40c0d79da746b52b9fae8ea3359b9bb18dd291a14dfd36a37277a9da0dacffffc22c4faf009ff33e93e17ba1cc742cfce2743d30c0c5581303db96060ce02ece19ee81ddc852ce0a18d966d95ac17a4713ea16741b6281d2ce3b615e5b7e5a2f6256d86e320acf9f8314f8e629b9833376d6af735523e90feb03b5fc5b852a9e06ea0479a279e97aea24a9e531939ec357ec659de3ae0aaf533f06abda0821812dea18c4570ca2bd62e959145995a5c240049bd23b30ceca43df5b9e1d1b1825a38eea3fba1ab483a8c5dffa065223fd3d3fe4990db1446a3852e8a554b09ab38b2ab63a008d1fdad48e273d812bcc26ca516fad09ac05e38383a2b718e553aac42197a1f0d4220e7ab5d8c6880524ca1c0d488d02321fb901309007b4937afa9df486022abf4f6c2363bf8513c34bbc586e43ae19f4b90fe5461024b159c34176aa94b8d4cb69d2326c83af1d6b805cdda1d6240183a2f1b41cd3a993a0aa9d1d77eb8c4aff7b8c980105ed55df6ce7a9a02c50f6381efb564e9fc5bd8d2619a68c37cf9c78df91e87d5fa2cf816ae9dab068fc86dc741cda14e84e3dac26ebcfb
    SignatureAlgorithmOID1.2.840.113549.1.1.5
    IsCertificateAuthorityTrue
    SerialNumber611fb0a400000000001d
    Version3

    Imports

    Expand
    • ntoskrnl.exe
    • ntoskrnl.exe
    • HAL.dll

    Imported Functions

    Expand
    • rand
    • srand
    • RtlInitUnicodeString
    • RtlGetVersion
    • KeDelayExecutionThread
    • ExAllocatePoolWithTag
    • ExFreePoolWithTag
    • ExSystemTimeToLocalTime
    • MmGetSystemRoutineAddress
    • IofCompleteRequest
    • IoCreateDevice
    • IoCreateSymbolicLink
    • IoDeleteDevice
    • IoGetCurrentProcess
    • ObReferenceObjectByHandleWithTag
    • ObfDereferenceObject
    • ObfDereferenceObjectWithTag
    • MmIsAddressValid
    • PsGetProcessExitStatus
    • PsIsThreadTerminating
    • PsLookupProcessByProcessId
    • PsLookupThreadByThreadId
    • PsGetThreadProcess
    • PsIsSystemThread
    • ObOpenObjectByPointerWithTag
    • KeBugCheckEx
    • ExAllocatePool
    • NtQuerySystemInformation
    • ExFreePoolWithTag
    • IoAllocateMdl
    • MmProbeAndLockPages
    • MmMapLockedPagesSpecifyCache
    • MmUnlockPages
    • IoFreeMdl
    • KeQueryActiveProcessors
    • KeSetSystemAffinityThread
    • KeRevertToUserAffinityThread
    • DbgPrint
    • KeQueryPerformanceCounter

    Exported Functions

    Expand

    Sections

    Expand
    • .text
    • .rdata
    • .data
    • .pdata
    • INIT
    • .YUC
    • .(~z
    • .A<b
    • .reloc

    Signature

    Expand
    {
  "Certificates": [
    {
      "IsCertificateAuthority": false,
      "SerialNumber": "38de06b8be15187f107e04f8b1138977",
      "Signature": "261c8eec3489c246498e8f65d4f68bd4f1e569760f9653601c877ad5f755bdd0ff729e81ced79aa051ea3ad404a74ba13cfeba87cc44b1960463280c5e44162713038f4d63e5737afe06427b934e403eb31fe76ae672575dc7fc72dd9fb199680d9fc4a8dcb31662b45423e6e738418066d9e14968a0d3e85c3c8e820692d6bcc203e675079a773681d8ddb91b81a808c2f1be43fba6343d82403ea067bbc6a3fe28a67de9a82707dfbbd8e1e06e977676242b32467bd02351843eefe183b603c04af960d6777e2958b7d88d6512190b3af858188be9e9bc3cd1e2fe92adbec1bca5885ab6d021a048f258b55a0ff5b7d55d94db1694840771f54b63862a9cd2",
      "SignatureAlgorithmOID": "1.2.840.113549.1.1.5",
      "Subject": "C=CN, ST=Shandong, L=Zaozhuang, O=Bopsoft, CN=Bopsoft",
      "TBS": {
        "MD5": "1e71dd41570c4bb591861555853106a3",
        "SHA1": "1cb57dd770235af6c117b995e9c52909a0e44684",
        "SHA256": "4ebff6116837c32889b3bcbabd82137e69a7d30ea1458d8e8e9a1861379761f3",
        "SHA384": "738b7cc310cd6dd8166ed2317a8bc065a3fe0245b8b0ff73a781f0902c3a6c29f5e133f2f43e040f49aec974a618063c"
      },
      "ValidFrom": "2018-03-02 00:00:00",
      "ValidTo": "2018-11-28 23:59:59",
      "Version": 3
    },
    {
      "IsCertificateAuthority": true,
      "SerialNumber": "47974d7873a5bcab0d2fb370192fce5e",
      "Signature": "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",
      "SignatureAlgorithmOID": "1.2.840.113549.1.1.5",
      "Subject": "C=US, O=Thawte, Inc., CN=Thawte Code Signing CA , G2",
      "TBS": {
        "MD5": "e3a93dc2a8a8a668fdbb286bfe9afab5",
        "SHA1": "95795d2aa2a554a423bc8c6e5b0a016d14887d35",
        "SHA256": "d8844186775bddbccaf3dc017064df7d760fd4b85c5d07561a3efd7da950f89e",
        "SHA384": "78d972495720b43a6470b18ae1226bcca20707628087717a9364c14ca053ba264e6d149718b103542d9942200138a69d"
      },
      "ValidFrom": "2010-02-08 00:00:00",
      "ValidTo": "2020-02-07 23:59:59",
      "Version": 3
    },
    {
      "IsCertificateAuthority": true,
      "SerialNumber": "611fb0a400000000001d",
      "Signature": "2dcc71b5e8ba94ff5ee64467007b6afc412c3ee70e41855ab12a932ba95b89f2f72b499c8003f297b8e760a80ed7fd5de545467594f4ed1c9de166228b61fb29f2c6a8bdf387c98f7f47e1c058b64a1aa2e7f718606969e083069e26c775c40c0d79da746b52b9fae8ea3359b9bb18dd291a14dfd36a37277a9da0dacffffc22c4faf009ff33e93e17ba1cc742cfce2743d30c0c5581303db96060ce02ece19ee81ddc852ce0a18d966d95ac17a4713ea16741b6281d2ce3b615e5b7e5a2f6256d86e320acf9f8314f8e629b9833376d6af735523e90feb03b5fc5b852a9e06ea0479a279e97aea24a9e531939ec357ec659de3ae0aaf533f06abda0821812dea18c4570ca2bd62e959145995a5c240049bd23b30ceca43df5b9e1d1b1825a38eea3fba1ab483a8c5dffa065223fd3d3fe4990db1446a3852e8a554b09ab38b2ab63a008d1fdad48e273d812bcc26ca516fad09ac05e38383a2b718e553aac42197a1f0d4220e7ab5d8c6880524ca1c0d488d02321fb901309007b4937afa9df486022abf4f6c2363bf8513c34bbc586e43ae19f4b90fe5461024b159c34176aa94b8d4cb69d2326c83af1d6b805cdda1d6240183a2f1b41cd3a993a0aa9d1d77eb8c4aff7b8c980105ed55df6ce7a9a02c50f6381efb564e9fc5bd8d2619a68c37cf9c78df91e87d5fa2cf816ae9dab068fc86dc741cda14e84e3dac26ebcfb",
      "SignatureAlgorithmOID": "1.2.840.113549.1.1.5",
      "Subject": "C=US, O=thawte, Inc., OU=Certification Services Division, OU=(c) 2006 thawte, Inc. , For authorized use only, CN=thawte Primary Root CA",
      "TBS": {
        "MD5": "a3f222107d4e1085e73b5b589c2f480b",
        "SHA1": "b94aa26cd77c48d91a53ac44506cbd255e1d362c",
        "SHA256": "a39ed0d6fd4eb1a6f7fed60f726e23eae668b7591bc004644625d22c701213fa",
        "SHA384": "64b7643e4146016cbf83c911eb67e4601b6bb8d66f8ee8dcee67b815f91770d86ab23678b984430f22a963e5484881b7"
      },
      "ValidFrom": "2011-02-22 19:31:57",
      "ValidTo": "2021-02-22 19:41:57",
      "Version": 3
    }
  ],
  "CertificatesInfo": "",
  "Signer": [
    {
      "Issuer": "C=US, O=Thawte, Inc., CN=Thawte Code Signing CA , G2",
      "SerialNumber": "38de06b8be15187f107e04f8b1138977",
      "Version": 1
    }
  ],
  "SignerInfo": ""
}

    source

    last_updated: 2024-09-26