学步园

rootkit is hot today, everybody wanna write a rootkit, if you often browse USENET, you're gonna see many guys ask for
how to get an undocumented kernel structure, or something how to hook a kernel routine, it's too bad, these techniques
are also widely used by some *famous* commercial products, of course, rootkits.
i usually run IceSword to check what's going on if i find my box is in a *unusual* status, IceSword is cool and can locate many of malicious software esp. kernel mode malware. one day i find:

apparently, this is a highly suspicious module required being striked! (or my bad, i will be striked, it's a shame ! ) .
because i have no 2 boxes for real kernel debugging, so i hook up the WinDbg to do a quick local kernel debug to
catch the bad guy living in my sweet machine.

lkd> lm
start    end        module name
00de0000 00e11000   kext       (deferred)            
01000000 0106b000   windbg     (deferred)            
01690000 01799000   ext        (deferred)            
01900000 01953000   exts       (deferred)            
01960000 01acd000   kdexts     (deferred)            
02000000 022b7000   dbgeng     (deferred)            
03000000 03118000   dbghelp    (deferred)            
4b210000 4b261000   MSCTF      (deferred)            
4c510000 4c53e000   msctfime   (deferred)            
63090000 63099000   LPK        (deferred)            
71b30000 71b41000   MPR        (deferred)            
74ae0000 74b41000   USP10      (deferred)            
74b80000 74bf0000   RICHED20   (deferred)            
75d60000 75d87000   apphelp    (deferred)            
76180000 7619d000   IMM32      (deferred)            
77370000 77407000   COMCTL32   (deferred)            
774b0000 775e4000   ole32      (deferred)            
77b60000 77b68000   VERSION    (deferred)            
77b70000 77bca000   msvcrt     (deferred)            
77bd0000 77c18000   GDI32      (deferred)            
77c20000 77cbf000   RPCRT4     (deferred)            
77cd0000 77dd3000   comctl32_77cd0000   (deferred)            
77e10000 77ea1000   USER32     (deferred)            
77eb0000 77f02000   SHLWAPI    (deferred)            
77f30000 77fdc000   ADVAPI32   (deferred)            
7c800000 7c92b000   kernel32   (deferred)            
7c930000 7ca00000   ntdll      (deferred)            
7ca10000 7d1f0000   SHELL32    (deferred)            
80800000 80a6b000   nt         (pdb symbols)          e:/symbol/ntoskrnl.pdb/4106003FF97D4BCBA99245BF2172A8C12/ntoskrnl.pdb
80a6b000 80a8a000   hal        (deferred)            
b9092000 b90c2000   kmixer     (deferred)            
b9110000 b9123000   sysaudio   (deferred)            
b9123000 b913e000   wdmaud     (deferred)            
b9436000 b94507c0   naiavf5x   (deferred)            
b985d000 b9860b80   vmnetuserif   (deferred)            
b99a1000 b99ff000   srv        (deferred)            
b9ac7000 b9b18000   HTTP       (deferred)            
b9b18000 b9b2dc80   vmx86      (deferred)            
ba426000 ba442000   dump_atapi   (deferred)            
ba442000 ba458000   Udfs       (deferred)            
ba458000 ba46d000   Cdfs       (deferred)            
ba495000 ba4bc000   ipnat      (deferred)            
ba4bc000 ba4cd000   Fips       (deferred)            
ba4cd000 ba543000   mrxsmb     (deferred)            
ba543000 ba573000   rdbss      (deferred)            
ba573000 ba59d000   afd        (deferred)            
ba59d000 ba5ce000   netbt      (deferred)            
ba5ce000 ba62f000   tcpip      (deferred)            
ba62f000 ba648000   ipsec      (deferred)            
ba708000 ba71c000   usbhub     (deferred)            
ba7bc000 ba7fc000   update     (deferred)            
ba7fc000 ba833000   rdpdr      (deferred)            
ba8d3000 ba8e6000   raspptp    (deferred)            
ba8e6000 ba900000   ndiswan    (deferred)            
ba91e000 ba933000   rasl2tp    (deferred)            
ba933000 ba945000   i8042prt   (deferred)            
ba945000 ba95d000   parport    (deferred)            
ba95d000 ba970000   serial     (deferred)            
ba970000 ba985000   drmk       (deferred)            
ba985000 ba9ae000   portcls    (deferred)            
ba9ae000 ba9d6000   ks         (deferred)            
ba9d6000 ba9e9000   redbook    (deferred)            
ba9e9000 ba9fe000   cdrom      (deferred)            
ba9fe000 baa28000   USBPORT    (deferred)            
baa28000 baa43000   VIDEOPRT   (deferred)            
baa43000 baa66700   s3gnbm     (deferred)            
bf800000 bf9d0000   win32k     (deferred)            
bf9d0000 bf9e6000   dxg        (deferred)            
bf9e6000 bfa3e080   s3gnb      (deferred)            
f71f9000 f7218000   Mup        (deferred)            
f7218000 f724e000   NDIS       (deferred)            
f724e000 f72e3000   Ntfs       (deferred)            
f72e3000 f730a000   KSecDD     (deferred)            
f730a000 f732f000   fltMgr     (deferred)            
f732f000 f7342000   CLASSPNP   (deferred)            
f7342000 f7361000   SCSIPORT   (deferred)            
f7361000 f737d000   Unknown_Module_f7361000   (deferred)   // NOTE: This is the unknow driver.
f737d000 f73a6000   volsnap    (deferred)            
f73a6000 f73d1000   dmio       (deferred)            
f73d1000 f73f7000   ftdisk     (deferred)            
f73f7000 f740c000   pci        (deferred)            
f740c000 f7440000   ACPI       (deferred)            
f7440000 f7465e00   d347bus    (deferred)            
f7487000 f7490000   WMILIB     (deferred)            
f7497000 f74a6000   isapnp     (deferred)            
f74a7000 f74b4000   PCIIDEX    (deferred)            
f74b7000 f74c7000   MountMgr   (deferred)            
f74c7000 f74d2000   PartMgr    (deferred)            
f74d7000 f74e7000   disk       (deferred)            
f74e7000 f74f3000   Dfs        (deferred)            
f74f7000 f7506000   viaagp     (deferred)            
f7507000 f7511000   crcdisk    (deferred)            
f7517000 f7521000   flpydisk   (deferred)            
f7527000 f7533000   vga        (deferred)            
f7537000 f7542000   Msfs       (deferred)            
f7547000 f7554000   Npfs       (deferred)            
f7557000 f7565000   msgpc      (deferred)            
f7567000 f7575460   mvstdi5x   (deferred)            
f7577000 f7584000   netbios    (deferred)            
f7597000 f75a4000   wanarp     (deferred)            
f75b7000 f75c0000   dump_WMILIB   (deferred)            
f75c7000 f75d0000   ndisuio    (deferred)            
f75d7000 f75e1000   Dxapi      (deferred)            
f75e7000 f75f5000   processr   (deferred)            
f75f7000 f7600000   watchdog   (deferred)            
f7607000 f7611b00   viaudio    (deferred)            
f7617000 f7620e00   fetnd5     (deferred)            
f7627000 f7632000   fdc        (deferred)            
f7637000 f7641000   serenum    (deferred)            
f7647000 f7651000   mouclass   (deferred)            
f7657000 f7661000   kbdclass   (deferred)            
f7667000 f7670000   ndistapi   (deferred)            
f7677000 f7686000   raspppoe   (deferred)            
f7687000 f7692000   TDI        (deferred)            
f7697000 f76a2000   ptilink    (deferred)            
f76a7000 f76b0000   raspti     (deferred)            
f76b7000 f76c6000   termdd     (deferred)            
f76c7000 f76d0000   mssmbios   (deferred)            
f76f7000 f7705000   NDProxy    (deferred)            
f7707000 f770f000   kdcom      (deferred)            
f770f000 f7717000   BOOTVID    (deferred)            
f7717000 f771e000   viaide     (deferred)            
f771f000 f7726000   dmload     (deferred)            
f777f000 f7784200   RTL8139    (deferred)            
f7787000 f778c180   usbuhci    (deferred)            
f778f000 f7795a00   usbehci    (deferred)            
f7797000 f779f000   msmpu401   (deferred)            
f779f000 f77a7000   fsvga      (deferred)            
f77a7000 f77af000   audstub    (deferred)            
f77c7000 f77cf000   Fs_Rec     (deferred)            
f77cf000 f77d6000   Null       (deferred)            
f77d7000 f77de000   Beep       (deferred)            
f77df000 f77e7000   mnmdd      (deferred)            
f77e7000 f77ef000   RDPCDD     (deferred)            
f77ef000 f77f7000   rasacd     (deferred)            
f77f7000 f77fe000   dxgthk     (deferred)            
f781f000 f7824400   vmnetbridge   (deferred)            
f784f000 f7853b00   hcmon      (deferred)            
f7857000 f785e000   parvdm     (deferred)            
f790b000 f790d800   VMNET      (deferred)            
f795f000 f7961780   gameenum   (deferred)            
f7983000 f7985580   vmnetadapter   (deferred)            
f7987000 f7988480   d347prt    (deferred)            
f799b000 f799c300   kldbgdrv   (deferred)            
f79a5000 f79a6280   swenum     (deferred)            
f79af000 f79b0580   USBD       (deferred)            
f7a47000 f7a48b40   VMparport   (deferred)            
f7b7c000 f7b7c600   SetupNT    (deferred)     

first, let check the driver and device object, if the driver need process I/O request, usually it require a driver object and
a device object (in most cases, this is true, we don't talk about very sophisticate stuff here),

lkd> !object /driver
Object: e1007898  Type: (84e84488) Directory
    ObjectHeader: e1007880
    HandleCount: 0  PointerCount: 88
    Directory Object: e10016d8  Name: Driver

    Hash Address  Type          Name
    ---- -------  ----          ----
     00  84b863f0 Driver        Beep
         84c34cb8 Driver        NDIS
         84c67a18 Driver        KSecDD
     01  84b9be30 Driver        FsVga
         84bcb9b8 Driver        Mouclass
         84b198e8 Driver        Raspti
     03  848628a0 Driver        Fips
         84bcbad8 Driver        Kbdclass
     04  84b90240 Driver        VgaSave
         84b159e0 Driver        NDProxy
     05  84b1ff38 Driver        Ptilink
         84e2a040 Driver        MountMgr
         843d4aa8 Driver        wdmaud
     06  84b74a78 Driver        Processor
         84481228 Driver        SetupNT
     07  84e2aa88 Driver        dmload
         84e29178 Driver        isapnp
     08  84b46c18 Driver        redbook
         84df6438 Driver        atapi
     10  84b8c358 Driver        RasAcd
         84b15c20 Driver        VMnetAdapter
         84e2a860 Driver        dmio
         84b53760 Driver        IpNat
     11  84bcac30 Driver        audstub
         84b92040 Driver        usbuhci
         84bc2e38 Driver        Win32k
         8446b198 Driver        VMnetuserif
     12  84b6e870 Driver        usbhub
         84b16b08 Driver        swenum
         84b19a08 Driver        rdpdr
         84b68ce0 Driver        ms_mpu401
         8464ea30 Driver        VMnetBridge
     13  84b53650 Driver        RDPCDD
         84b1fd10 Driver        Update
         84b1ce18 Driver        RasPppoe
         84b468e0 Driver        FETNDIS
         84851680 Driver        HTTP
     14  843d5618 Driver        kldbgdrv
         84b1b158 Driver        TermDD
         84e2ad60 Driver        Ftdisk
         84e7bae8 Driver        d347bus
         843d43d0 Driver        sysaudio
     15  84bca670 Driver        Rasl2tp
         84b55500 Driver        Fdc
     16  84614ce8 Driver        Parvdm
     18  84b1c040 Driver        PptpMiniport
         84bd91c0 Driver        serenum
         84c33df0 Driver        crcdisk
         84e35168 Driver        WMIxWDM
         84e354c0 Driver        ACPI_HAL
     19  84649f00 Driver        hcmon
     21  84864778 Driver        NaiAvTdi1
         8486e600 Driver        NetBT
         84e29280 Driver        viaagp
     22  84b6b3e8 Driver        Cdrom
         84b1e220 Driver        mssmbios
         84b46d38 Driver        VIAudio
     23  84df7f38 Driver        ViaIde
         84350530 Driver        kmixer
     24  8484f6d8 Driver        Wanarp
         849df620 Driver        Tcpip
         84b54400 Driver        mnmdd
         84b9b670 Driver        gameenum
     25  84e2a1a0 Driver        VolSnap
     28  84b91178 Driver        Null
         84b51040 Driver        usbehci
         84e28e30 Driver        d347prt
     29  84bb3da0 Driver        IPSec
         84c7df38 Driver        Disk
         84e50c18 Driver        PCI
     30  84b94f38 Driver        Serial
         84b1d140 Driver        NdisTapi
         84b1f040 Driver        NdisWan
         84df6540 Driver        PartMgr
     31  849df040 Driver        Gpc
     32  84e32420 Driver        ACPI
         84bde158 Driver        vmx86
     33  84b90458 Driver        Flpydisk
         84bb6e90 Driver        rtl8139
         84e81ec8 Driver        PnpManager
         8467e1b8 Driver        VMparport
         84b93da0 Driver        NaiAvFilter1
     34  849eeba8 Driver        AFD
         8464d040 Driver        Ndisuio
     35  84b95660 Driver        Parport
     36  84b9bf38 Driver        i8042prt
         84b5a858 Driver        S3SavageNB

all seems to be OK. then i get stucked for a while. after a few minutes, i think we can get started to dump the raw memory
of the driver image, perhaps i can find some clue if we're lucky enough (if the code is not extremely obfuscated)

lkd> dc f7361000 f737cfff
(Note: because the output is too large, so i only list most interesting bits here)

f736ccf0  735c3a64 74727672 72645c6d 72657669  d:/srvrtm/driver
f736cd00  74735c73 6761726f 64695c65 74615c65  s/storage/ide/at
f736cd10  5c697061 74696e69 cc00632e cccccccc  api/init.c..

f736e220  00730055 00720065 006c0053 00760061  U.s.e.r.S.l.a.v.
f736e230  00440065 00760065 00630069 00540065  e.D.e.v.i.c.e.T.
f736e240  006d0069 006e0069 004d0067 0064006f  i.m.i.n.g.M.o.d.
f736e250  00410065 006c006c 0077006f 00640065  e.A.l.l.o.w.e.d.
f736e260  00000032 00000000 00730055 00720065  2.......U.s.e.r.
f736e270  0061004d 00740073 00720065 00650044  M.a.s.t.e.r.D.e.
f736e280  00690076 00650063 00690054 0069006d  v.i.c.e.T.i.m.i.
f736e290  0067006e 006f004d 00650064 006c0041  n.g.M.o.d.e.A.l.
f736e2a0  006f006c 00650077 00320064 00000000  l.o.w.e.d.2.....

f736e7e0  6d6d6f43 63696e75 6f697461 7265506e  CommunicationPer
f736e7f0  65687069 006c6172 4e6e6547 00007465  ipheral.GenNet..
f736e800  0074654e 6964654d 68436d75 65676e61  Net.MediumChange
f736e810  72655072 65687069 006c6172 436e6547  rPeripheral.GenC
f736e820  676e6168 00007265 6e616843 00726567  hanger..Changer.
f736e830  6974704f 446c6163 506b7369 70697265  OpticalDiskPerip
f736e840  61726568 0000006c 4f6e6547 63697470  heral...GenOptic
f736e850  00006c61 6974704f 006c6163 6e616353  al..Optical.Scan
f736e860  5072656e 70697265 61726568 0000006c  nerPeripheral...
f736e870  536e6547 6e6e6163 00007265 6e616353  GenScanner..Scan
f736e880  0072656e 6f526443 7265506d 65687069  ner.CdRomPeriphe
f736e890  006c6172 436e6547 6d6f5264 00000000  ral.GenCdRom....
f736e8a0  6f526443 0000006d 6d726f57 69726550  CdRom...WormPeri
f736e8b0  72656870 00006c61 576e6547 006d726f  pheral..GenWorm.    // I'm scared by *GenWorm* !
f736e8c0  6d726f57 00000000 636f7250 6f737365  Worm....Processo
f736e8d0  72655072 65687069 006c6172 506e6547  rPeripheral.GenP
f736e8e0  65636f72 726f7373 00000000 636f7250  rocessor....Proc
f736e8f0  6f737365 00000072 6e697250 50726574  essor...PrinterP
f736e900  70697265 61726568 0000006c 506e6547  eripheral...GenP
f736e910  746e6972 00007265 6e697250 00726574  rinter..Printer.
f736e920  65706154 69726550 72656870 00006c61  TapePeripheral..
f736e930  536e6547 65757165 6169746e 0000006c  GenSequential...
f736e940  75716553 69746e65 00006c61 6b736944  Sequential..Disk
f736e950  69726550 72656870 00006c61 446e6547  Peripheral..GenD
f736e960  006b7369 6b736944 00000000 ca01ac1c  isk.Disk........

f7375140  00650052 00690067 00740073 00790072  R.e.g.i.s.t.r.y.
f7375150  004d005c 00630061 00690068 0065006e  /.M.a.c.h.i.n.e.
f7375160  0053005c 00730079 00650074 005c006d  /.S.y.s.t.e.m./.
f7375170  00750043 00720072 006e0065 00430074  C.u.r.r.e.n.t.C.
f7375180  006e006f 00720074 006c006f 00650053  o.n.t.r.o.l.S.e.
f7375190  005c0074 006f0043 0074006e 006f0072  t./.C.o.n.t.r.o.
f73751a0  005c006c 006e0050 00000070 00440000  l./.P.n.p.....D.
f73751b0  00730069 00620061 0065006c 00690046  i.s.a.b.l.e.F.i.
f73751c0  006d0072 00610077 00650072 0061004d  r.m.w.a.r.e.M.a.
f73751d0  00700070 00720065 004c0000 00670065  p.p.e.r...L.e.g.
f73751e0  00630061 00440079 00740065 00630065  a.c.y.D.e.t.e.c.
f73751f0  00690074 006e006f 004c0000 00670065  t.i.o.n...L.e.g.
f7375200  00630061 00440079 00740065 00630065  a.c.y.D.e.t.e.c.
f7375210  00690074 006e006f cccc0000 cccccccc  t.i.o.n.......

f7369df0  0044005c 00760065 00630069 005c0065  /.D.e.v.i.c.e./.
f7369e00  00640049 005c0065 00640049 00440065  I.d.e./.I.d.e.D.
f7369e10  00760065 00630069 00500065 00640025  e.v.i.c.e.P.%.d.
f7369e20  00250054 004c0064 00640025 0025002d  T.%.d.L.%.d.-.%.
f7369e30  00000078 cccccccc ff8bcccc 81ec8b55  x...........U...

great, the driver seems to have some relationship with ATAPI.sys, and has
interest in storage device, but there is a bad sign since i found GenWorm,
i'm exciting (scared of course!). The most important clues are the registry path
and the device name format string. i first try to find the device who's name match
the pattern /Device/Ide/IdeDeviceP*T*L*, it's a reasonable check, i think.

lkd> !object /device/ide
Object: e1438230  Type: (84e84488) Directory
    ObjectHeader: e1438218
    HandleCount: 0  PointerCount: 9
    Directory Object: e1007980  Name: Ide

    Hash Address  Type          Name
    ---- -------  ----          ----
     03  84df4b58 Device        IdeDeviceP0T0L0-3
         84e25028 Device        IdePort0
     04  84df2028 Device        IdePort1
         84df7278 Device        PciIde0Channel0-0
     19  84e2bd10 Device        PciIde0Channel1-1
     32  84e2b030 Device        PciIde0
     33  84df4410 Device        IdeDeviceP1T0L0-e

mmm, not bad. let me dump the device fields.

lkd> dt nt!_DEVICE_OBJECT 84df4b58
   +0x000 Type             : 3
   +0x002 Size             : 0x234
   +0x004 ReferenceCount   : 0
   +0x008 DriverObject     : 0x84df6438
   +0x00c NextDevice       : 0x84df2028
   +0x010 AttachedDevice   : 0x84e28cb0
   +0x014 CurrentIrp       : (null)
   +0x018 Timer            : (null)
   +0x01c Flags            : 0x5050
   +0x020 Characteristics  : 0x101
   +0x024 Vpb              : (null)
   +0x028 DeviceExtension  : 0x84df4c10
   +0x02c DeviceType       : 2
   +0x030 StackSize        : 1 ''
   +0x034 Queue            : __unnamed
   +0x05c AlignmentRequirement : 1
   +0x060 DeviceQueue      : _KDEVICE_QUEUE
   +0x074 Dpc              : _KDPC
   +0x094 ActiveThreadCount : 0
   +0x098 SecurityDescriptor : 0xe15e8658
   +0x09c DeviceLock       : _KEVENT
   +0x0ac SectorSize       : 0
   +0x0ae Spare1           : 1
   +0x0b0 DeviceObjectExtension : 0x84df4d90
   +0x0b4 Reserved         : (null)

lkd> !devstack 84df4b58
  !DevObj   !DrvObj            !DevExt   ObjectName
  84b95748  /Driver/redbook    84b95800 
  84b95030  /Driver/Cdrom      84b950e8  CdRom0
  84e28cb0  /Driver/ACPI       84e311a8  00000066
> 84df4b58  /Driver/atapi      84df4c10  IdeDeviceP0T0L0-3
!DevNode 84e28b08 :
  DeviceInst is "IDE/CdRomSAMSUNG_DVD-ROM_SD-816B_________________H001____/5&782cc20&0&0.0.0"
  ServiceName is "cdrom"

lkd> dt nt!_DRIVER_OBJECT 0x84df6438
   +0x000 Type             : 4
   +0x002 Size             : 168
   +0x004 DeviceObject     : 0x84df4410
   +0x008 Flags            : 0x12
   +0x00c DriverStart      : (null)
   +0x010 DriverSize       : 0
   +0x014 DriverSection    : 0x84e84d08
   +0x018 DriverExtension  : 0x84df64e0
   +0x01c DriverName       : _UNICODE_STRING "/Driver/atapi"
   +0x024 HardwareDatabase : 0x809f9260  "/REGISTRY/MACHINE/HARDWARE/DESCRIPTION/SYSTEM"
   +0x028 FastIoDispatch   : (null)
   +0x02c DriverInit       : 0xf737957f     Unknown_Module_f7361000!GsDriverEntry+0
   +0x030 DriverStartIo    : 0xf7368dec     Unknown_Module_f7361000!IdePortStartIo+0
   +0x034 DriverUnload     : 0x84b01c50     +ffffffff84b01c50
   +0x038 MajorFunction    : [28] 0x84b01bf8     +ffffffff84b01bf8

this indicate that the device object is created by ATAPI.sys. however, no ATAPI in lm command output.
ATAPI may have been hijacked by some bad guys.

let's dump the dispatch routines:
lkd> dps 0x84df6438+0x38 L20
84df6470  84b01bf8
84df6474  84b01bf8
84df6478  84b01bf8
84df647c  84b01bf8
84df6480  84b01bf8
84df6484  84b01bf8
84df6488  84b01bf8
84df648c  84b01bf8
84df6490  84b01bf8
84df6494  84b01bf8
84df6498  84b01bf8
84df649c  84b01bf8
84df64a0  84b01bf8
84df64a4  84b01bf8
84df64a8  84b01bf8
84df64ac  84b01bf8
84df64b0  84b01bf8
84df64b4  84b01bf8
84df64b8  84b01bf8
84df64bc  84b01bf8
84df64c0  84b01bf8
84df64c4  84b01bf8
84df64c8  84b01bf8
84df64cc  84b01bf8
84df64d0  84b01bf8
84df64d4  84b01bf8
84df64d8  84b01bf8
84df64dc  84b01bf8
84df64e0  84df6438
84df64e4  f7373208
84df64e8  00000000
84df64ec  000c000a

then check the assembler code:
lkd> uf 84b01bf8
84b01bf8  jmp     84b01bfc

84b01bfc  push    ebx
84b01bfd  lea     ebx,[84b01c5c]
84b01c03  push    ebx
84b01c04  push    eax
84b01c05  push    esp
84b01c06  call    nt!IoAcquireVpbSpinLock (80848c58)

84b01c0b  mov     ebx,[ebx]
84b01c0d  call    dword ptr [ebx+0x90]
84b01c13  call    nt!IoReleaseVpbSpinLock (8084ab53)
84b01c18  mov     eax,[ebx+0x8]
84b01c1b  sahf
84b01c1c  pushfd
84b01c1d  mov     eax,[esp+0x14]
84b01c21  push    eax
84b01c22  mov     eax,[eax+0x60]
84b01c25  movzx   eax,byte ptr [eax]
84b01c28  push    dword ptr [esp+0x14]
84b01c2c  call    dword ptr [ebx+eax*4+0x20]
84b01c30  mov     [esp+0x4],eax
84b01c34  push    eax
84b01c35  push    esp
84b01c36  call    nt!IoAcquireVpbSpinLock (80848c58)
84b01c3b  call    dword ptr [ebx+0x94]
84b01c41  pop     eax
84b01c42  popfd
84b01c43  push    eax
84b01c44  jnz     84b01c0b

84b01c46  call    nt!IoReleaseVpbSpinLock (8084ab53)
84b01c4b  pop     eax
84b01c4c  pop     ebx
84b01c4d  ret     0x8

examine the instruction -> call    dword ptr [ebx+0x90]
lkd> u poi(poi(84b01c5c)+90)
f7455a4e  lock    inc dword ptr [ebx+0xc]
f7455a52  ret
f7455a53  lock    dec dword ptr [ebx+0xc]
f7455a57  jnz     f7455a61
f7455a59  pushad
f7455a5a  push    ebx
f7455a5b  call    f7443cf2
f7455a60  popad

lkd> u poi(84b5fbe4+0x94)
*** ERROR: Module load completed but symbols could not be loaded for d347bus.sys
d347bus+0x15a53:
f7455a53  lock    dec dword ptr [ebx+0xc]
f7455a57  jnz     d347bus+0x15a61 (f7455a61)
f7455a59  pushad
f7455a5a  push    ebx
f7455a5b  call    d347bus+0x3cf2 (f7443cf2)
f7455a60  popad
f7455a61  ret
f7455a62  push    ebp

lkd> lmvm d347bus
start    end        module name
f7440000 f7465e00   d347bus    (no symbols)          
    Loaded symbol image file: d347bus.sys
    Image path: d347bus.sys
    Image name: d347bus.sys
    Timestamp:        Sun Aug 22 21:31:09 2004 (4128A01D)
    CheckSum:         00034FBA
    ImageSize:        00025E00
    Translations:     0000.04b0 0000.04e0 0409.04b0 0409.04e0

so d347bus hijack ATAPI, scan the code address 84b01bf8 
lkd> !pool 84b01bf8 
Pool page 84b01bf8 region is Nonpaged pool
 84b01000 size:  ba0 previous size:    0  (Allocated)  RTLm
 84b01ba0 size:    8 previous size:  ba0  (Free)       ....
 84b01ba8 size:   48 previous size:    8  (Allocated)  NDpf
*84b01bf0 size:  108 previous size:   48  (Allocated) *V386
  Owning component : Unknown (update pooltag.txt)
 84b01cf8 size:   18 previous size:  108  (Free)       MntA
 84b01d10 size:   80 previous size:   18  (Allocated)  PXh.
 84b01d90 size:    8 previous size:   80  (Free)       Thre
 84b01d98 size:   18 previous size:    8  (Allocated)  Wmip
 84b01db0 size:  100 previous size:   18  (Allocated)  NDmo
 84b01eb0 size:  150 previous size:  100  (Allocated)  WanJ

So actually ATAPI's dispatch routine is hijaced by d347bus.sys with a
ExAllocatePoolWithTag and copy the instructions to the allocated pool
to hook the dispatch routines.

the atapi driver object is listed in the debug output, however, the module has been
modified, so the debugger can not recognize the ATAPI.sys since no pdb symbol
match the checksum, i think.

there're some obfuscated code in the image, this is interesting. and i am still have concern
on what's the heck GenWorm mean?! may i can build a repro in VMWare to trace
d347bus.sys.
d347bus.sys is bus driver of Daemon Tool, basically it should do no harm to my
computer, however, if d347bus.sys is hijacked by another driver, this will become
more complex, resreved for future striking!

ok, now, go to bed.