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Pivot into private VPC networks using a VPN connection
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vpc_vpn_pivot
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LICENSE Initial commit Jun 29, 2019
README.md
requirements.txt status command Oct 7, 2019
vpc-vpn-pivot Latest Oct 6, 2019

README.md

Pivoting into VPC networks

This tool automates the creation of a VPN between the attacker's workstation and an AWS resource in the target VPC with the objective of connecting to other AWS services, such as EC2 instances, which are not accessible from the Internet.

vpn-vpc-pivot-demo

Or watch this demo on asciinema.

Use case

You are performing a cloud penetration test and gained access to a set of AWS credentials. The target infrastructure uses VPCs and most of the interesting services are private (can only be accessed by other hosts connected to the same VPC or subnet).

This tool completely automates the process of creating a VPN between your workstation and the target VPC so you can connect to those private services.

Depending on the permissions associated with the compromised credentials the tool will use different techniques to create and maintain the VPN service running. For example, if the credentials have permissions for EC2 and ACM then an AWS Client VPN is created and the openvpn client is used to connect to it.

Supported services

This tool will try to create the VPN connection using different techniques, based on the permissions associated with the compromised credentials. The supported services for creating the VPN are:

The following will be implemented in the future:

  • EC2
  • Lambda
  • LightSail
  • Fargate

Noise

The tool will generate a lot of CloudTrail logs and if anyone is paying attention you will get detected and blocked.

Installation

The vpc-vpn-pivot tool uses Python 3.6. The full installation steps are:

git clone https://github.com/andresriancho/vpc-vpn-pivot.git
cd vpc-vpn-pivot

pip3 install requirements.txt
sudo apt-get install openvpn

Usage

This command will setup the SSL certificates, routes and other resources required for the AWS Client VPN to work:

./vpc-vpn-pivot create --profile={profile-name} --subnet-id={subnet-id}

The profile needs to contain compromised credentials for the target AWS account and be stored in ~/.aws/credentials/, the VPC ID can be obtained using aws ec2 describe-vpcs.

Everything is ready! Just connect your workstation to the VPC using openvpn:

sudo ./vpc-vpn-pivot connect

./vpc-vpn-pivot status
route -n
nmap -sS ...

The script needs to be run using sudo because openvpn requires root privileges to create the tun interface.

Once connected to the VPC you should be able to inspect the IP address range with ifconfig and run any tool, such as nmap to find open services on the VPC.

Use the following commands to disconnect from the VPN and remove all remote resources created for the VPN to work:

./vpc-vpn-pivot disconnect
./vpc-vpn-pivot purge

Troubleshooting

vpc-vpn-pivot keeps current state and the names of all the created resources in the state file (~/.vpc-vpn-pivot/state). This file is useful if you need to manually kill the openvpn process or remove the AWS resources.

Warning

In order to create an AWS Client VPN we import two certificates into the target's AWS account. There is a hard-limit of 20 imported certificates per year, by using this tool you are reducing the number of available ACM certificates.

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