Custom Python RAT Builder
This week I already wrote a diary about "code reuse" in the malware landscape[1] but attackers also have plenty of tools to generate new samples on the fly. When you received a malicious Word documents, it has not been prepared by hand, it has been for sure automatically generated. Except if you're a "nice" target for attackers and victim of some kind of "APT". The keyword here is "automation". If defenders try to automate as much as possible, attackers too!
Today, Discord is often used by attackers as a nice C2 server[2] and we can find plenty of Python malware that interact with Discord. Most of them are info stealers. I already found plenty of such scripts but today I spotted something else. A script to generate your own RAT ("Remote Access Tool"). The script has a VT score of 7/56[3] (SHA256:f13433cc26702e7b6116e36629625cc798d0ad4b26aa782a551a38ec3dc8ab23). I had to fine tune a bit the script to make it work in my sandbox but the usage is pretty simple:
The script is very simple, it contains the RAT standard code and the provided token is injected into it:
file.write("""import winreg import ctypes import sys import os import ssl import random import threading import time import cv2 import subprocess import discord from comtypes import CLSCTX_ALL from discord.ext import commands from ctypes import * import asyncio import discord from discord import utils token = '~~TOKENHERE~~' global appdata appdata = os.getenv('APPDATA') client = discord.Client() bot = commands.Bot(command_prefix='!') ... ... """.replace("~~TOKENHERE~~", tokenbot))
You can see that the script asks if the script must be compiled. This is achieved using the pyinstaller[4] module.Once completed, you will have a fully standalone PE file ready to be sent to your victims. I uploaded my sample to VT and it got a score of 10/67, not so bad from an attacker's point of view.
Here is a quick overview of the supported bot commands:
!kill | Kill the bot (disconnect from Discord) |
!dumpkeylogger | Dump captured keys to the Discoard channel |
!exit | Exit the bot (process) |
!windowstart | Start Window logging |
!windowstop | Stop Window logging |
!screenshot | Take a screenshot |
!webcampic | Take picture with the webcam |
!message | Display a message on the desktop (via MessageBoxW()) |
!wallpaper | Change the desktop background |
!upload | Upload a file |
!shell | Remote command execution |
!download | Download a file |
!cd | Change current directory |
!help | Because attackers need some help too :-) |
!write | Write something (like on the keyboard) |
!clipboard | Get clipboard data |
!sysinfo | Collect system information |
!geolocate | Collect GeoIP details about the victim |
!admincheck | Check if bot is running with admin privileges |
!uacbypass | Try UAC privileges escalation |
!startkeylogger | Start the keylogger |
!stopkeylogger | Stop the keylogger |
!blockinput | Annoy the user[5] |
!unblockinput | Release the user |
!streamwebcam | Start webcam recording |
!stopwebcam | Stop webcal recording |
!getdiscordinfo | What about the Discord session? |
!streamscreen | Record multiple screenshots |
!stopscreen | Stop screen streaming |
!shutdown | Stop the victim's computer |
!restart | Reboot the victim's computer |
!logoff | Logoff the current user |
!bluescreen | Generate a BSOD (!) |
!currentdir | Print current directory |
!displaydir | List files in the direcotry |
!dateandtime | Return the victim's computer date & time |
!listprocess | Return the list of running processes |
!prockill | Try to kill a process |
!recscreen | Record a video from screen |
!reccam | Record a video from webcam |
!recaudio | Record a wav from the internal mic |
!delete | Delete a file |
!disableantivirus | Try to disable the AV |
!disablefirewall | Try to disable the firewall |
!audio | Play a record file |
!selfdestruct | Try to wipe the computer |
!windowspass | Try to collect system credentials |
!displayoff | Turn off display |
!displayon | Turn on display |
!hide | Try to hide a file ("attrib +h") |
!unhide | Try to unhide a file |
!decode | Decode Base64 |
!ejectcd | Open CD tray |
!retractcd | Close CD tray |
!critproc | Set process as critical |
!website | Visit a webpage |
!distaskmgr | Try to disable the task manager |
!enbtaskmgr | Try to re-enable the task manager |
!getwifipass | Exfiltrate Wifi passwords |
[1] https://isc.sans.edu/forums/diary/Code+Reuse+In+the+Malware+Landscape/28216/
[2] https://crawl3r.github.io/2020-01-25/DaaC2
[3] https://www.virustotal.com/gui/file/f13433cc26702e7b6116e36629625cc798d0ad4b26aa782a551a38ec3dc8ab23/details
[4] https://pypi.org/project/pyinstaller/
[5] https://isc.sans.edu/forums/diary/A+Simple+Batch+File+That+Blocks+People/28212/
Xavier Mertens (@xme)
Xameco
Senior ISC Handler - Freelance Cyber Security Consultant
PGP Key
Reverse-Engineering Malware: Advanced Code Analysis | Singapore | Nov 18th - Nov 22nd 2024 |
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