d0cc79b2-a789-4cf3-9a88-25bdabb79416

devhost.sys :inline :inline

Description

devhost.sys is a WHQL attestation-signed kernel driver that exposes arbitrary memory read primitives to usermode. The device object at \.\devhost has no ACL beyond a device handle. At load, the driver reads IA32_LSTAR MSR to locate ntoskrnl base via backward MZ walk, then dynamically resolves APIs (including MmMapIoSpace and MmCopyMemory) using a djb2-style hash algorithm over the PE export directory. Only 11 benign imports are visible statically. The system CR3 is leaked to user-mode at DriverEntry. Authentication uses a hardcoded magic cookie via IOCTL 0x28E017. IOCTL 0x28E01B accepts a caller-supplied CR3 and target virtual address, performs a manual 4-level x64 page-table walk (PML4-PDPT-PD-PT), and reads physical memory via MmMapIoSpace. Additional IOCTLs expose NtBuildNumber, PsLoadedModuleList, and per-CPU KPCR CurrentThread. Nextron Research noted that these primitives are tailor-made for credential theft (e.g. LSASS memory dumping), though no confirmed malicious usage has been publicly documented. WHQL attestation signed with active cert (Nov 2025-Nov 2026). SpcSpOpusInfo identifies the submitter as Shenzhen Aolian Information Security Technology Co Ltd.

  • UUID: d0cc79b2-a789-4cf3-9a88-25bdabb79416
  • Created: 2026-04-22
  • Author: Michael Haag
  • Acknowledgement: Florian Roth | @cyaboratory

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Commands

sc.exe create devhost binPath=C:\windows\temp\devhost.sys type=kernel && sc.exe start devhost
Use CasePrivilegesOperating System
Arbitrary kernel memory read via page-table walk and MmMapIoSpacekernelWindows 10

Detections

YARA 🏹

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Exact Match

with header and size limitation

Threat Hunting

without header and size limitation

Renamed

for renamed driver files

Sigma 🛡️

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Names

detects loading using name only

Hashes

detects loading using hashes only

Sysmon 🔎

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Block

on hashes

Alert

on hashes

Resources


  • https://x.com/nextaboratory/status/1914729845602783262

    • Known Vulnerable Samples

    PropertyValue
    Filenamedevhost.sys
    Creation Timestamp2026-01-17 16:10:13
    MD5a8bafdb454162ba3776e551f6b552f8e
    SHA1ba349735882fef5e60d8b6f7791d6220bccebcb5
    SHA256ee8844ffd3879190fb389b0f613cb2dcdcd83375cf0a6994170a648c5ca8c479
    Authentihash MD513090f2fc8ac6d7d78c581370eb3351e
    Authentihash SHA1c1c1f350e55413ac335b1f25dbbb87ac1b9c8f9e
    Authentihash SHA256c3ad079fc6516504775869a9667e154dc6710a8dc39771fe81b1f15f5c3bdf5d
    RichPEHeaderHash MD56d4f45050eba836593a9fddff29db793
    RichPEHeaderHash SHA15c6ce550d1acbe2162aa36b47383f10ff1576d27
    RichPEHeaderHash SHA256f34b4979e896de802a9df1dcf322125ed13da225806904a997ec687b0a1d4bbc

    Download

    Certificates

    Expand
    Certificate 330000013c4a61fb3578d2b6dd00000000013c
    FieldValue
    ToBeSigned (TBS) MD593354b540685ae615b51e692ea0895de
    ToBeSigned (TBS) SHA1b38cd5d491c85bd55e9b111e98430171a01e9515
    ToBeSigned (TBS) SHA256037c041a283132dc57d29bc339b4d0d006787e32ac0a60afd7206c41c9fbf61f
    SubjectC=US, ST=Washington, L=Redmond, O=Microsoft Corporation, CN=Microsoft Windows Hardware Compatibility Publisher
    ValidFrom2025-11-13 19:59:40
    ValidTo2026-11-10 19:59:40
    Signature86e91c9dd77bcbe24e9c811c4ec9c47116d9d554243f04666bef14828edbfeb665280fa10b643a59d05c4db8b5f2bae0657af9a75457236e455f956ed7ba65f7e8019355d00e322f681ab15f14718b34bff1e50d8cde1217dc158c31a875b17fa45f015b4b2a30c471d43345257c729d83c2287716b3d19c177ed341da95687f8af92cfebc42e1e4439eb4304762e17feb85a09316afe8153e4783a98153d91249d29da0bca831ea6ccd93bace88fc284e82987df65bcd8ab0263a2da5e178e710c26e8abec12fe398782d1f1bc669ec9c5cbf3010f8e2600133a59fb8269daba61e5b2facee4f96ba19f9cfaef3fdb21e933a65c3245f6de70cb08f28f2c818
    SignatureAlgorithmOID1.2.840.113549.1.1.11
    IsCertificateAuthorityFalse
    SerialNumber330000013c4a61fb3578d2b6dd00000000013c
    Version3
    Certificate 610baac1000000000009
    FieldValue
    ToBeSigned (TBS) MD5a569061297e8e824767dbc3184a69bea
    ToBeSigned (TBS) SHA1adbb26a587a8f44b4fccaecb306f980d1c55a150
    ToBeSigned (TBS) SHA256cec1afd0e310c55c1dcc601ab8e172917706aa32fb5eaf826813547fdf02dd46
    SubjectC=US, ST=Washington, L=Redmond, O=Microsoft Corporation, CN=Microsoft Windows Third Party Component CA 2012
    ValidFrom2012-04-18 23:48:38
    ValidTo2027-04-18 23:58:38
    Signature5a8a67daccd5fd0d264177bf0a4678b4b3de12692b7723c2652f015fd203f461ba509d2e8c3972f36c3e6ab11e766decb7f382dcccbbc56970287366173f54ebee011648c446d91b80ae813a8d0f796d68b09eea2d3f39d3ca387ebd5e7c086e19dcc6c2f438336861e2524783e1000156d2bacb878205310a418b4ee77f5f5fed5fd3392d45eba213bffd1ec298417161165fc80a70257c59693124e471e70abb0417f79f721ec9d2bb1abe3d02fe090cb243b4591a99539396215fe0d6b72601429536ac27fdbef48577683d18bdf4be98882211865216f345ec0397107087a37043713cdbc98603170cf5735bc67de15c64edd7c548d7ed32e2d1aad3cfa7f6574e61f977eb67f288b3de00da038fd08a34373e1dd862b8d2b1f3e12f8b723b81967c6ffcec667672601b24f2a0896d5b6d002eef28dd868705c2b4b9e5be64c22af24a155c98e2c42785ff52e3627e0fb2020bd766c70ab2d33d200414503259830a7d9bed5a38120152ba2f5e20728e4af1fde771028c3be107bec973f4dd47d8b4efb4a4b330b9893e76cab90098567eabea8ab8a5d038ab6977130b142fe9aa411ff7babd3a2b348aee0aab63e663f788248e200d2b3b9de3c24952ac9f1f0e393b5dd46e506ae67d523aaa7c3315290d265e0158a74ea93d7a846f743f609fe4324f3600af6d71d33ea646655f8174f1fec171da4ca0415a82ddf11f
    SignatureAlgorithmOID1.2.840.113549.1.1.11
    IsCertificateAuthorityTrue
    SerialNumber610baac1000000000009
    Version3

    Imports

    Expand
    • ntoskrnl.exe

    Imported Functions

    Expand
    • KeRevertToUserAffinityThread
    • KeSetSystemAffinityThread
    • KeQueryActiveProcessors
    • MmProbeAndLockPages
    • MmUnlockPages
    • IoAllocateMdl
    • IoFreeMdl
    • __C_specific_handler
    • MmSystemRangeStart
    • MmUserProbeAddress
    • NtBuildNumber

    Exported Functions

    Expand

    Sections

    Expand
    • .text
    • .rdata
    • .data
    • .pdata
    • PAGE
    • INIT
    • .reloc

    Signature

    Expand
    {
  "Certificates": [
    {
      "CertificateType": "Leaf (Code Signing)",
      "IsCA": false,
      "IsCertificateAuthority": false,
      "IsCodeSigning": true,
      "SerialNumber": "330000013c4a61fb3578d2b6dd00000000013c",
      "Signature": "86e91c9dd77bcbe24e9c811c4ec9c47116d9d554243f04666bef14828edbfeb665280fa10b643a59d05c4db8b5f2bae0657af9a75457236e455f956ed7ba65f7e8019355d00e322f681ab15f14718b34bff1e50d8cde1217dc158c31a875b17fa45f015b4b2a30c471d43345257c729d83c2287716b3d19c177ed341da95687f8af92cfebc42e1e4439eb4304762e17feb85a09316afe8153e4783a98153d91249d29da0bca831ea6ccd93bace88fc284e82987df65bcd8ab0263a2da5e178e710c26e8abec12fe398782d1f1bc669ec9c5cbf3010f8e2600133a59fb8269daba61e5b2facee4f96ba19f9cfaef3fdb21e933a65c3245f6de70cb08f28f2c818",
      "SignatureAlgorithmOID": "1.2.840.113549.1.1.11",
      "Subject": "C=US, ST=Washington, L=Redmond, O=Microsoft Corporation, CN=Microsoft Windows Hardware Compatibility Publisher",
      "TBS": {
        "MD5": "93354b540685ae615b51e692ea0895de",
        "SHA1": "b38cd5d491c85bd55e9b111e98430171a01e9515",
        "SHA256": "037c041a283132dc57d29bc339b4d0d006787e32ac0a60afd7206c41c9fbf61f",
        "SHA384": "bbef5ad51ba2a76ba3f0e39459837c9533a56420db0da55814511346155922c98ae905d6541df5a79895ce1a51d53491"
      },
      "ValidFrom": "2025-11-13 19:59:40",
      "ValidTo": "2026-11-10 19:59:40",
      "Version": 3
    },
    {
      "CertificateType": "CA",
      "IsCA": true,
      "IsCertificateAuthority": true,
      "IsCodeSigning": false,
      "SerialNumber": "610baac1000000000009",
      "Signature": "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",
      "SignatureAlgorithmOID": "1.2.840.113549.1.1.11",
      "Subject": "C=US, ST=Washington, L=Redmond, O=Microsoft Corporation, CN=Microsoft Windows Third Party Component CA 2012",
      "TBS": {
        "MD5": "a569061297e8e824767dbc3184a69bea",
        "SHA1": "adbb26a587a8f44b4fccaecb306f980d1c55a150",
        "SHA256": "cec1afd0e310c55c1dcc601ab8e172917706aa32fb5eaf826813547fdf02dd46",
        "SHA384": "e947cac936803f5683196e4ff1b259096073395d0b908522ddce90d57597c9f7b57f7ddcdbe021ba863d843c340da8ba"
      },
      "ValidFrom": "2012-04-18 23:48:38",
      "ValidTo": "2027-04-18 23:58:38",
      "Version": 3
    }
  ],
  "CertificatesInfo": "",
  "Signer": [
    {
      "Issuer": "C=US, ST=Washington, L=Redmond, O=Microsoft Corporation, CN=Microsoft Windows Third Party Component CA 2012",
      "SerialNumber": "330000013c4a61fb3578d2b6dd00000000013c",
      "Version": 1
    }
  ],
  "SignerInfo": ""
}

    source

    last_updated: 2026-04-23