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Assembly Source File | 1993-08-05 | 14.9 KB | 472 lines

;───────────────────────────────────────────────────────────────────────────── ; Black Wolf's File Protection Utilities 2.1s ; ;EncrEXE - This program encrypts specified file and attaches the decryption ; code from EN_EXE onto the file so that it will decrypt on ; each execution. It utilizes ULTIMUTE .93ß to protect then EN_EXE ; code from easy manipulation. ; ;LISCENSE: ; Released As Freeware - These files may be distributed freely. ; ;Any modifications made to this program should be listed below the solid line, ;along with the name of the programmer and the date the file was changed. ;Also - they should be commented where changed. ; ;NOTE THAT MODIFICATION PRIVILEDGES APPLY ONLY TO THIS VERSION (2.1s)! ;I'd appreciate notification of any modifications if at all possible, ;reach me through the address listed in the documentation file (bwfpu21s.doc). ; ;DISCLAIMER: The author takes ABSOLUTELY NO RESPONSIBILITY for any damages ;resulting from the use/misuse of this program/file. The user agrees to hold ;the author harmless for any consequences that may occur directly or ;indirectly from the use of this program by utilizing this program/file ;in any manner. ;───────────────────────────────────────────────────────────────────────────── ;Modifications: ; None as of 08/05/93 - Initial Release. .model tiny .radix 16 .code org 100 extrn _ULTMUTE:near, _END_ULTMUTE:byte, Init_Rand:near extrn Get_Rand:near start: call GetFilename call Init_Rand call Get_Rand mov [Key1],ax call Get_Rand mov [Key2],ax call Get_Rand mov [Key3],ax call Get_Rand mov [Key4],ax call Do_File mov ax,4c00 int 21 ;--------------------------------------------------------------------------- GetFilename: mov ah,09 mov dx,offset Message int 21 mov dx,offset Filename_Data mov al,60 call gets ret ;--------------------------------------------------------------------------- ;--------------------------------------------------------------------------- Message: db 'EncrEXE 2.0 (c) 1993 Black Wolf Enterprises.',0a,0dh db 'Enter Filename To Protect -> $' ;--------------------------------------------------------------------------- gets: mov ah,0a push bx mov bx,dx mov byte ptr ds:[bx],al mov byte ptr ds:[bx+1],0 pop bx int 21 push bx mov bx,dx mov al,byte ptr ds:[bx+1] xor ah,ah add bx,ax mov byte ptr ds:[bx+2],0 pop bx ret ;--------------------------------------------------------------------------- Save_Header: mov ax,word ptr [exeheader+0e] ;Save old SS mov word ptr [Old_SS],ax mov ax,word ptr [exeheader+10] ;Save old SP mov word ptr [Old_SP],ax mov ax,word ptr [exeheader+14] ;Save old IP mov word ptr [Old_IP],ax mov ax,word ptr [exeheader+16] ;Save old CS mov word ptr [Old_CS],ax ret Do_File: mov ax,3d02 mov dx,offset Filename int 21 jnc Terminate_NOT jmp Terminate Terminate_NOt: xchg bx,ax call GetTime call BackupFile mov ah,3f mov cx,1a mov dx,offset EXEheader int 21 cmp word ptr [EXEheader],'ZM' ;not EXE file. je IsEXE jmp close_file IsEXE: call Save_Header mov ax,4200 xor cx,cx xor dx,dx ;Go back to beginning int 21 mov ax,word ptr [EXEheader+08] mov cl,4 ;convert header to bytes shl ax,cl mov word ptr [HeaderSize],ax mov cx,ax mov dx,offset Header ;Load header mov ah,3f int 21 call Encrypt_Entire_File mov ax,4202 xor cx,cx ;Go end xor dx,dx int 21 mov cl,4 shr ax,cl inc ax shl ax,cl mov cx,dx ;Pad file mov dx,ax mov ax,4200 int 21 push ax dx call calculate_CSIP ;calculate starting ;point. mov ah,40 mov dx,offset Set_Segs mov cx,end_set_segs-set_segs int 21 push bx mov si,offset begin_password ;On Entry -> CS=DS=ES mov di,offset _END_ULTMUTE ;SI=Source, DI=Destination mov bx,word ptr [exeheader+14] ;BX=Next Entry Point add bx,end_set_segs-set_segs mov cx,end_password-begin_password+1 ;CX=Size to Encrypt add cx,word ptr [headersize] ;add in EXE header mov ax,1 ;AX=Calling Style call _ULTMUTE ;On Return -> CX=New Size pop bx pop dx ax ;DX:AX = unmodified ;file size. push cx bx add cx,end_set_segs-set_segs call calculate_size pop bx cx mov dx,offset _END_ULTMUTE mov ah,40 int 21 mov ax,4200 xor dx,dx xor cx,cx int 21 mov ah,40 mov cx,1a mov dx,offset EXEheader int 21 mov cx,word ptr [headersize] sub cx,1a jz Close_File Zero_Header: push cx mov ah,40 mov cx,1 mov dx,offset zero int 21 pop cx loop Zero_Header Close_File: mov ax,5701 mov cx,word ptr cs:[Time] mov dx,word ptr cs:[Date] ;restore date/time int 21 mov ah,3e int 21 ret GetTime: mov ax,5700 int 21 mov word ptr cs:[Time],cx mov word ptr cs:[Date],dx ret Time dw 0 Date dw 0 Terminate: mov ah,09 mov dx,offset BadFile int 21 ret BadFile db 'Error Opening File.',07,0dh,0a,24 zero db 0,0 calculate_CSIP: push ax mov cl,4 mov ax,word ptr [exeheader+8] ;Get header length ;and convert it to shl ax,cl ;bytes. mov cx,ax pop ax sub ax,cx ;Subtract header sbb dx,0 ;size from file ;size for memory ;adjustments mov cl,0c ;Convert DX into shl dx,cl ;segment Address mov cl,4 push ax ;Change offset (AX) into shr ax,cl ;segment, except for last add dx,ax ;digit. Add to DX and shl ax,cl ;save DX as new CS, put pop cx ;left over into CX and sub cx,ax ;store as the new IP. mov word ptr [exeheader+16],dx ;Set new CS:IP mov word ptr [exeheader+10],0fffe ;Set new SP mov word ptr [exeheader+0e],dx ;Set new SS = CS mov word ptr [exeheader+14],cx mov word ptr [exeheader+6],0 ;Set 0 relocation items. ret calculate_size: add ax,cx ;Add virus size to DX:AX adc dx,0 push ax ;Save offset for later mov cl,7 shl dx,cl ;convert DX to pages mov cl,9 shr ax,cl add ax,dx inc ax mov word ptr [exeheader+04],ax ;save # of pages pop ax ;Get offset mov dx,ax shr ax,cl ;Calc remainder shl ax,cl ;in last page sub dx,ax mov word ptr [exeheader+02],dx ;save remainder ret Set_Segs: push es ds push cs cs pop es ds End_Set_Segs: Encrypt_Entire_File: mov ah,3f mov cx,400 mov dx,offset Encrypt_Buffer ;Read in buffer full int 21 or ax,ax jz Add_Protection_Code ;None left? leave... push ax call EncryptBytes ;Encrypt buffer pop ax push ax xor dx,dx sub dx,ax mov cx,0ffff ;Go back to where we mov ax,4201 ;read from int 21 mov ah,40 pop cx mov dx,offset Encrypt_Buffer ;Write it back int 21 cmp ax,400 ;Buffer full? loop... je Encrypt_Entire_File Add_Protection_Code: ret EncryptBytes: ;This algorithm needs help.... push ax bx cx dx si di mov si,offset Encrypt_Buffer mov di,si mov cx,200 Decrypt_Loop: lodsw ror ax,1 add ax,[Key4] xor ax,[Key3] rol ax,1 sub ax,[Key2] xor ax,[Key1] stosw loop Decrypt_Loop pop di si dx cx bx ax ret dw 0 dw 0 Filename_data dw 0 Filename db 80 dup(0) Exeheader db 1a dup(0) Encrypt_Buffer dw 400 dup(0) HeaderSize dw 0 BackupFile: mov si,offset Filename mov cx,80 Find_Eofn: lodsb cmp al,'.' je FoundDot or al,al jz FoundZero loop Find_Eofn jmp Terminate FoundZero: mov byte ptr [si-1],'.' inc si FoundDot: mov word ptr [si],'LO' mov byte ptr [si+2],'D' mov byte ptr [si+3],0 mov dx,offset Filename mov word ptr [SourceF],bx mov ah,3c xor cx,cx int 21 jnc GCreate jmp Terminate GCreate: mov word ptr cs:[Destf],ax BackLoop: mov ah,3f mov bx,word ptr cs:[Sourcef] mov cx,400 mov dx,offset Encrypt_Buffer int 21 mov cx,ax mov ah,40 mov bx,word ptr cs:[Destf] mov dx,offset Encrypt_Buffer int 21 cmp ax,400 je BackLoop DoneBack: mov ah,3e mov bx,word ptr cs:[Destf] int 21 mov ax,4200 xor cx,cx xor dx,dx mov bx,word ptr cs:[Sourcef] int 21 ret SourceF dw 0 DestF dw 0 begin_password: ;code from en_exe ;------------------------------------------------------------------------ db 0e8h, 02dh, 01h, 058h, 050h, 02eh, 089h, 086h, 076h, 02h db 02eh, 089h, 086h, 0fh, 01h, 033h, 0dbh, 05h, 010h, 00h db 08ch, 0c9h, 02bh, 0c8h, 0d1h, 0e1h, 083h, 0d3h, 00h, 0ebh db 0ch, 090h, 0eah, 0d1h, 0e3h, 0d1h, 0e1h, 083h, 0d3h, 00h db 0ebh, 0bh, 0ffh, 0d1h, 0e3h, 0d1h, 0e1h, 083h, 0d3h, 00h db 0ebh, 0edh, 09ah, 08eh, 0c0h, 08eh, 0d8h, 033h, 0f6h, 033h db 0ffh, 0e8h, 0fbh, 00h, 0ebh, 01h, 0eah, 0adh, 033h, 086h db 080h, 02h, 03h, 086h, 082h, 02h, 0d1h, 0c8h, 033h, 086h db 084h, 02h, 02bh, 086h, 086h, 02h, 0d1h, 0c0h, 0abh, 053h db 051h, 08bh, 0c6h, 08bh, 0d8h, 0b1h, 04h, 0d3h, 0e8h, 0d3h db 0e0h, 03bh, 0c3h, 075h, 0dh, 083h, 0eeh, 010h, 083h, 0efh db 010h, 01eh, 058h, 040h, 08eh, 0d8h, 08eh, 0c0h, 059h, 05bh db 0e2h, 0c9h, 083h, 0fbh, 00h, 074h, 06h, 04bh, 0ebh, 0c1h db 0e8h, 0b6h, 00h, 050h, 01eh, 033h, 0c0h, 08eh, 0d8h, 08dh db 086h, 0d5h, 01h, 087h, 06h, 00h, 00h, 050h, 08ch, 0c8h db 087h, 06h, 02h, 00h, 050h, 033h, 0c9h, 02eh, 0c7h, 086h db 0a4h, 01h, 090h, 090h, 0f7h, 0f1h, 058h, 087h, 06h, 02h db 00h, 058h, 087h, 06h, 00h, 00h, 01fh, 058h, 07h, 01fh db 02eh, 08bh, 086h, 076h, 02h, 05h, 010h, 00h, 02eh, 03h db 086h, 07ch, 02h, 0fah, 08eh, 0d0h, 02eh, 08bh, 0a6h, 07eh db 02h, 0fbh, 033h, 0c0h, 08bh, 0f0h, 08bh, 0f8h, 02eh, 0ffh db 0aeh, 078h, 02h, 02eh, 08bh, 086h, 076h, 02h, 05h, 010h db 00h, 02eh, 01h, 086h, 07ah, 02h, 0e8h, 01h, 00h, 0cfh db 050h, 053h, 051h, 052h, 06h, 01eh, 056h, 057h, 055h, 08bh db 0ddh, 02eh, 08bh, 0afh, 0a0h, 02h, 02eh, 08bh, 08fh, 08eh db 02h, 0bh, 0c9h, 074h, 027h, 03h, 0ebh, 02eh, 0c5h, 0b6h db 088h, 02h, 02bh, 0ebh, 08ch, 0d8h, 02eh, 03h, 087h, 076h db 02h, 05h, 010h, 00h, 08eh, 0d8h, 02eh, 08bh, 087h, 076h db 02h, 05h, 010h, 00h, 01h, 04h, 083h, 0c5h, 04h, 0e8h db 017h, 00h, 0e2h, 0d9h, 05dh, 05fh, 05eh, 01fh, 07h, 05ah db 059h, 05bh, 058h, 0c3h, 05dh, 0ebh, 01h, 0eah, 055h, 081h db 0edh, 03h, 01h, 0c3h, 0c3h, 0ebh, 014h, 090h, 0eah, 0e8h db 02ch, 00h, 0ebh, 06h, 090h, 0e8h, 026h, 00h, 0ebh, 0f5h db 0bh, 0edh, 074h, 0f7h, 05dh, 0ebh, 0e9h, 055h, 033h, 0edh db 0ebh, 0efh, 050h, 072h, 06fh, 074h, 065h, 063h, 074h, 069h db 06fh, 06eh, 020h, 062h, 079h, 020h, 042h, 06ch, 061h, 063h db 06bh, 020h, 057h, 06fh, 06ch, 066h, 0e4h, 021h, 034h, 02h db 0e6h, 021h, 045h, 0c3h, 00h, 00h ;------------------------------------------------------------------------ Old_IP dw 0 Old_CS dw 0fff0 Old_SS dw 0fff0 Old_SP dw 0 Key1 dw 0 Key2 dw 0 Key3 dw 0 Key4 dw 0 ;------------------------------------------------------------------------ end_password: Header: db 800 dup(0) ;leave space for ultimute with db (0)'s end start