m0n1x90/elfxtractCTF/PWN 챌린지를 위한 자동화된 ELF 바이너리 분석 도구입니다. Radare2 및 r2ghidra를 사용하여 보안 완화(mitigations), ROP 가젯, PLT/GOT 테이블을 추출하고 ASM을 C로 디컴파일합니다. 잠재적인 버퍼 오버플로우, 포맷 스트링, 명령어 인젝션 취약점을 식별합니다.
ELFXtract는 ELF 바이너리를 열거하는 데 사용되는 자동화된 분석 도구입니다.
이 도구는 PWN 챌린지를 위해 특별히 개발되었으며 다양한 자동화 기능을 제공합니다.
ELF의 거의 모든 세부 정보를 표시하며, r2ghidra를 사용하여 어셈블리 코드를 C 코드로 역컴파일합니다.
Ghidra에서 ELF를 역컴파일하는 데는 더 많은 시간이 걸리지만, elfxtract에서는 몇 초 만에 역컴파일하여 표시합니다.
git clone https://github.com/AidenPearce369/elfxtract
cd elfxtract
chmod +x install.sh
./install.sh
pip install -r requirements.txt
elfxtract를 -a 플래그와 함께 실행하면 ELF의 모든 세부 정보를 나열할 수 있습니다.
ra@ubuntu:~/elfxtract$ python3 main.py --file programvuln -a
_____ _ ________ ___ _
| ___| | | ___\ \ / / | | |
| |__ | | | |_ \ V /| |_ _ __ __ _ ___| |_
| __|| | | _| / \| __| '__/ _` |/ __| __|
| |___| |____| | / /^\ \ |_| | | (_| | (__| |_
\____/\_____/\_| \/ \/\__|_| \__,_|\___|\__|
@aidenpearce369
***************************************************************************
> FILE INFO :
ELF Name : programvuln
ELF Type : ELF 64-bit LSB shared object
ELF Arch : x86-64
ELF SHA1 Hash : BuildID[sha1]=cf149d97ad1e895561080b1f5c317bc5bc1e8652
This binary is dynamically linked & not stripped
***************************************************************************
> SHARED OBJECT DEPENDENCY :
linux-vdso.so.1 (0x00007ffd525a4000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fd610d93000)
/lib64/ld-linux-x86-64.so.2 (0x00007fd610fa1000)
***************************************************************************
> ELF SECURITY MITIGATIONS :
RELRO : Full RELRO
STACK CANARY : No Canary found
NX BIT : NX disabled
PIE : PIE enabled
RPATH : No RPATH
RUNPATH : No RUNPATH
***************************************************************************
> POSSIBLE STRINGS :
nth paddr vaddr len size section type string
―――――――――――――――――――――――――――――――――――――――――――――――――――――――
0 0x00002008 0x00002008 31 32 .rodata ascii You have bypassed this function
1 0x00002028 0x00002028 12 13 .rodata ascii cat flag.txt
2 0x00002035 0x00002035 15 16 .rodata ascii Enter your name
3 0x00002045 0x00002045 13 14 .rodata ascii Your name is
***************************************************************************
> RODATA HEXDUMP :
0x00002000 01000200 00000000 596f7520 68617665 ........You have
0x00002010 20627970 61737365 64207468 69732066 bypassed this f
0x00002020 756e6374 696f6e00 63617420 666c6167 unction.cat flag
0x00002030 2e747874 00456e74 65722079 6f757220 .txt.Enter your
0x00002040 6e616d65 00596f75 72206e61 6d652069 name.Your name i
0x00002050 732000 s .
***************************************************************************
> ELF ENTRY POINT :
The entry point of the ELF is at 0x10c0
***************************************************************************
> HEADER MEMORY MAP :
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
PHDR 0x0000000000000040 0x0000000000000040 0x0000000000000040
0x00000000000002d8 0x00000000000002d8 R 0x8
INTERP 0x0000000000000318 0x0000000000000318 0x0000000000000318
0x000000000000001c 0x000000000000001c R 0x1
[Requesting program interpreter: /lib64/ld-linux-x86-64.so.2]
LOAD 0x0000000000000000 0x0000000000000000 0x0000000000000000
0x00000000000006a8 0x00000000000006a8 R 0x1000
LOAD 0x0000000000001000 0x0000000000001000 0x0000000000001000
0x00000000000002b5 0x00000000000002b5 R E 0x1000
LOAD 0x0000000000002000 0x0000000000002000 0x0000000000002000
0x00000000000001c8 0x00000000000001c8 R 0x1000
LOAD 0x0000000000002da0 0x0000000000003da0 0x0000000000003da0
0x0000000000000270 0x0000000000000278 RW 0x1000
DYNAMIC 0x0000000000002db0 0x0000000000003db0 0x0000000000003db0
0x00000000000001f0 0x00000000000001f0 RW 0x8
NOTE 0x0000000000000338 0x0000000000000338 0x0000000000000338
0x0000000000000020 0x0000000000000020 R 0x8
NOTE 0x0000000000000358 0x0000000000000358 0x0000000000000358
0x0000000000000044 0x0000000000000044 R 0x4
GNU_PROPERTY 0x0000000000000338 0x0000000000000338 0x0000000000000338
0x0000000000000020 0x0000000000000020 R 0x8
GNU_EH_FRAME 0x0000000000002054 0x0000000000002054 0x0000000000002054
0x000000000000004c 0x000000000000004c R 0x4
GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000
0x0000000000000000 0x0000000000000000 RWE 0x10
GNU_RELRO 0x0000000000002da0 0x0000000000003da0 0x0000000000003da0
0x0000000000000260 0x0000000000000260 R 0x1
***************************************************************************
[*] Loaded 14 cached gadgets for 'programvuln'
> ROP GADGETS :
0x1017 : add esp, 8;ret
0x1016 : add rsp, 8;ret
0x1221 : leave;ret
0x128c : pop r12;pop r13;pop r14;pop r15;ret
0x128e : pop r13;pop r14;pop r15;ret
0x1290 : pop r14;pop r15;ret
0x1292 : pop r15;ret
0x128b : pop rbp;pop r12;pop r13;pop r14;pop r15;ret
0x128f : pop rbp;pop r14;pop r15;ret
0x1193 : pop rbp;ret
0x1293 : pop rdi;ret
0x1291 : pop rsi;pop r15;ret
0x128d : pop rsp;pop r13;pop r14;pop r15;ret
0x101a : ret
***************************************************************************
> PLT TABLE :
__cxa_finalize : 0x1074
puts : 0x1084
system : 0x1094
printf : 0x10a4
gets : 0x10b4
***************************************************************************
> GOT TABLE :
_ITM_deregisterTMCloneTable : 0x3fd8
__libc_start_main : 0x3fe0
__gmon_start__ : 0x3fe8
_ITM_registerTMCloneTable : 0x3ff0
__cxa_finalize : 0x3ff8
puts : 0x3fb8
system : 0x3fc0
printf : 0x3fc8
gets : 0x3fd0
***************************************************************************
> FUNCTION TABLE :
__libc_csu_fini : 0x12a0
__libc_csu_init : 0x1230
win : 0x11a9
_start : 0x10c0
main : 0x11d6
***************************************************************************
> POSSIBLE USER DEFINED FUNCTIONS :
win : 0x11a9
main : 0x11d6
***************************************************************************
> ASSEMBLY AND DECOMPILED CODE :
[*] ASM - win :
┌ 45: sym.win ();
│ 0x000011a9 f30f1efa endbr64
│ 0x000011ad 55 push rbp
│ 0x000011ae 4889e5 mov rbp, rsp
│ 0x000011b1 488d3d500e00. lea rdi, str.You_have_bypassed_this_function ; 0x2008 ; "You have bypassed this function" ; const char *format
│ 0x000011b8 b800000000 mov eax, 0
│ 0x000011bd e8defeffff call sym.imp.printf ; int printf(const char *format)
│ 0x000011c2 488d3d5f0e00. lea rdi, str.cat_flag.txt ; 0x2028 ; "cat flag.txt" ; const char *string
│ 0x000011c9 b800000000 mov eax, 0
│ 0x000011ce e8bdfeffff call sym.imp.system ; int system(const char *string)
│ 0x000011d3 90 nop
│ 0x000011d4 5d pop rbp
└ 0x000011d5 c3 ret
[*] DECOMPILED CODE - win :
void sym.win(void)
{
sym.imp.printf("You have bypassed this function");
sym.imp.system("cat flag.txt");
return;
}
[*] ASM - main :
; DATA XREF from entry0 @ 0x10e1
┌ 77: int main (int argc, char **argv, char **envp);
│ ; var char *s @ rbp-0x40
│ 0x000011d6 f30f1efa endbr64
│ 0x000011da 55 push rbp
│ 0x000011db 4889e5 mov rbp, rsp
│ 0x000011de 4883ec40 sub rsp, 0x40
│ 0x000011e2 488d3d4c0e00. lea rdi, str.Enter_your_name ; 0x2035 ; "Enter your name" ; const char *s
│ 0x000011e9 e892feffff call sym.imp.puts ; int puts(const char *s)
│ 0x000011ee 488d45c0 lea rax, [s]
│ 0x000011f2 4889c7 mov rdi, rax ; char *s
│ 0x000011f5 b800000000 mov eax, 0
│ 0x000011fa e8b1feffff call sym.imp.gets ; char *gets(char *s)
│ 0x000011ff 488d3d3f0e00. lea rdi, str.Your_name_is_ ; 0x2045 ; "Your name is " ; const char *format
│ 0x00001206 b800000000 mov eax, 0
│ 0x0000120b e890feffff call sym.imp.printf ; int printf(const char *format)
│ 0x00001210 488d45c0 lea rax, [s]
│ 0x00001214 4889c7 mov rdi, rax ; const char *s
│ 0x00001217 e864feffff call sym.imp.puts ; int puts(const char *s)
│ 0x0000121c b800000000 mov eax, 0
│ 0x00001221 c9 leave
└ 0x00001222 c3 ret
[*] DECOMPILED CODE - main :
// WARNING: [r2ghidra] Failed to match type char * for variable s to Decompiler type:
undefined8 main(void)
{
undefined8 s;
sym.imp.puts("Enter your name");
sym.imp.gets(&s);
sym.imp.printf("Your name is ");
sym.imp.puts(&s);
return 0;
}
***************************************************************************
> VULNERABLE FUNCTIONS :
Possible vulnerability locations - Command Execution
0x000011ce e8bdfeffff call sym.imp.system ; int system(const char *string)
Possible vulnerability locations - Format String
0x000011bd e8defeffff call sym.imp.printf ; int printf(const char *format)
0x0000120b e890feffff call sym.imp.printf ; int printf(const char *format)
Possible vulnerability locations - Buffer Overflow
0x000011fa e8b1feffff call sym.imp.gets ; char *gets(char *s)
***************************************************************************
필요에 따라 인자를 전달하여 정보를 얻을 수도 있습니다.
ra@ubuntu:~/elfxtract$ python3 main.py -h
_____ _ ________ ___ _
| ___| | | ___\ \ / / | | |
| |__ | | | |_ \ V /| |_ _ __ __ _ ___| |_
| __|| | | _| / \| __| '__/ _` |/ __| __|
| |___| |____| | / /^\ \ |_| | | (_| | (__| |_
\____/\_____/\_| \/ \/\__|_| \__,_|\___|\__|
@aidenpearce369
***************************************************************************
usage: main.py [-h] -f FILE [-a] [-i] [-g] [--user-func] [--get-func GET_FUNC] [--asm-only]
[--decompiled-only] [-t]
optional arguments:
-h, --help show this help message and exit
-f FILE, --file FILE Path of the ELF
-a, --all Extract all info
-i, --info Displays basic info
-g, --gadgets Displays gadgets
--user-func Displays the details of user defined functions
--get-func GET_FUNC Displays the ASM & decompiled code of the given function
--asm-only Displays the ASM of ELF
--decompiled-only Displays the decompiled C code of ELF
-t, --tables Displays PLT, GOT & Function table
elfxtract는 PWN 바이너리 파싱에 최적화되어 개발되었습니다.
곧 시스템 바이너리 분석을 위한 새로운 기능이 추가될 예정입니다.
또한 자동 BOF 및 자동 ret2 익스플로잇 기능이 추가될 것입니다.