AWS Pen-Testing Laboratory – Pentesting Lab With A Kali Linux Instance Accessible Via Ssh And Wireguard VPN And With Vulnerable Instances In A Private Subnet

PenTesting laboratory deployed as IaC with Terraform on AWS. It deploys a Kali Linux instance accessible via ssh & wireguard VPN. Vulnerable instances in a private subnet.

NOTE:

• Ids only defined for region “eu-west-1”
• For other regions, kali ami id must be specified and metasploitable3 id (after building it)

Changelog

• [2021-06-02] AMI IDs changed to use Kali 2021.2
• [2021-03-10] Use new Kali version 2021.1

Diagram

Components

• Kali 2021.2 instance (private key is saved into kali.pem)
  • Wireguard VPN service: client file client_vpn.wg
  • Accessible via ssh/scp
  • Public Subnet 10.0.0.5/24
• Vulnerable machine “Metasploitable” (ami build is public)
  • Private subnet 10.0.1.5/24
• More vulnerable labs/machines/docker (to-be-done)

Features added

• User management
  • Automatically create non privileged users in kali instance with rsa
  • Wireguard VPN client file per user
• Command line audit logging in syslog
• auditd enabled with sudo_log and users_log keys for auditing user actions (see also ausearch command)
• ToDO: Forward terminal audit to CloudWatch or an S3 Bucket with write once policy

How-To

• Requirements:
  • Terraform CLI install guide
  • AWS CLI install guide
  • $PATH configured for AWS CLI & Terraform
  • AWS account and configure credentials via aws cli: aws configure
  • Kali Linux Subscription in AWS Marketplace (version 2020.04)
  • Metasploitable3 AMI image previously built (public AMI available for eu-west-1 region) see

Deploy

1. Enable/disable vulnerable instances to be deployed setting 0 or 1 in variables.tf:

variable "deploment-control" {
  type = map
  default = {
    #"instance" = 0 or 1, to disable or enable
    "metasploitable3" = 1
    "dvca" = 0
  }
  description = "Control which EC2 instances are deployed, 0 for none or 1"
}

2. Use terraform for deploy infraestructure

terraform init
terraform plan
terraform apply -auto-approve   

Outputs

Terraform outputs will show following entries:

• ssh connection command for kali user (root via sudo)
• wireguard client file for kali user will be automatically retrieved from kali server
• scp command to retrieve wireguard client file (just in case defined terraform local-exec command fails)
• For each of the normal users created in Kali instance
  • Private key file for ssh connection
  • Wireguard client file for VPN connectivity

Usage

Either connect to Kali via ssh or wireguard:

• SSH: (Only command line) Use autogenerated private key (see terraform output)

KALI_IP=<KALI_IP>     # configure kali public ip
ssh -i kali.pem -o StrictHostKeyChecking=no -o IdentitiesOnly=yes kali@${KALI_IP}

• Wireguard: Connect your local kali instance via wireguard (see client_vpn.wg generated file)

KALI_IP=<KALI_IP>     # configure kali public ip
scp -i kali.pem -o StrictHostKeyChecking=no IdentitiesOnly=yes kali@${KALI_IP}:/home/kali/client_vpn.wg .

####
(local_kali)$ sudo apt-get install –y wireguard 
(local_kali)$ sudo gedit /etc/wireguard/wg0.conf # copy contents of client_vpn.wg
(local_kali)$ sudo chmod 700 /etc/wireguard/wg0.conf
(local_kali)$ sudo wg-quick up wg0

(local_kali)$ ping 10.0.0.5  # test connectivity with kali instance in AWS

Destroy

terraform destroy -auto-approve

References

• rapid7 / metasploitable3 – license
• Kali 2021.2 AWS Marketplace
• terraform-aws-ec2-kali-linux