T1648 - Serverless Execution

Description from ATT&CK (opens in a new tab)

Adversaries may abuse serverless computing, integration, and automation services to execute arbitrary code in cloud environments. Many cloud providers offer a variety of serverless resources, including compute engines, application integration services, and web servers.

Adversaries may abuse these resources in various ways as a means of executing arbitrary commands. For example, adversaries may use serverless functions to execute malicious code, such as crypto-mining malware (i.e. Resource Hijacking (opens in a new tab)).(Citation: Cado Security Denonia) Adversaries may also create functions that enable further compromise of the cloud environment. For example, an adversary may use the IAM:PassRole permission in AWS or the iam.serviceAccounts.actAs permission in Google Cloud to add Additional Cloud Roles (opens in a new tab) to a serverless cloud function, which may then be able to perform actions the original user cannot.(Citation: Rhino Security Labs AWS Privilege Escalation)(Citation: Rhingo Security Labs GCP Privilege Escalation)

Serverless functions can also be invoked in response to cloud events (i.e. Event Triggered Execution (opens in a new tab)), potentially enabling persistent execution over time. For example, in AWS environments, an adversary may create a Lambda function that automatically adds Additional Cloud Credentials (opens in a new tab) to a user and a corresponding CloudWatch events rule that invokes that function whenever a new user is created.(Citation: Backdooring an AWS account) This is also possible in many cloud-based office application suites. For example, in Microsoft 365 environments, an adversary may create a Power Automate workflow that forwards all emails a user receives or creates anonymous sharing links whenever a user is granted access to a document in SharePoint.(Citation: Varonis Power Automate Data Exfiltration)(Citation: Microsoft DART Case Report 001) In Google Workspace environments, they may instead create an Apps Script that exfiltrates a user's data when they open a file.(Citation: Cloud Hack Tricks GWS Apps Script)(Citation: OWN-CERT Google App Script 2024)

Atomic Tests

• Atomic Test #1 - Lambda Function Hijack

Atomic Test #1 - Lambda Function Hijack

Modify an existing Lambda function to execute arbitrary code.

Supported Platforms: Iaas:aws

auto_generated_guid: 87a4a141-c2bb-49d1-a604-8679082d8b91

Inputs:

Attack Commands: Run with powershell!

Import-Module "PathToAtomicsFolder/T1648/src/T1648-1/LambdaAttack.ps1" -Force
$access_key = "#{access_key}"
$secret_key = "#{secret_key}"
$session_token = "#{session_token}"
$aws_profile = "#{profile}"
$region = "#{region}"
Set-AWSAuthentication -AccessKey $access_key -SecretKey $secret_key -SessionToken $session_token -AWSProfile $aws_profile -AWSRegion $region
Invoke-Terraform -TerraformCommand init -TerraformDirectory "PathToAtomicsFolder/T1648/src/T1648-1"
Invoke-Terraform -TerraformCommand apply -TerraformDirectory "PathToAtomicsFolder/T1648/src/T1648-1" -TerraformVariables @("profile=T1648-1", "region=$region")
Invoke-LambdaAttack -AWSProfile "T1648-1" -AWSRegion $region

Cleanup Commands:

Import-Module "PathToAtomicsFolder/T1648/src/T1648-1/LambdaAttack.ps1" -Force
$access_key = "#{access_key}"
$secret_key = "#{secret_key}"
$session_token = "#{session_token}"
$aws_profile = "#{profile}"
$region = "#{region}"
Set-AWSAuthentication -AccessKey $access_key -SecretKey $secret_key -SessionToken $session_token -AWSProfile $aws_profile -AWSRegion $region
Invoke-Terraform -TerraformCommand destroy -TerraformDirectory "PathToAtomicsFolder/T1648/src/T1648-1" -TerraformVariables @("profile=T1648-1", "region=$region")
Remove-MaliciousUser -AWSProfile "T1648-1"
Remove-TFFiles -Path "PathToAtomicsFolder/T1648/src/T1648-1/"

Dependencies: Run with powershell!

Description: The AWS PowerShell module must be installed.

Check Prereq Commands:

try {if (Get-InstalledModule -Name AWSPowerShell -ErrorAction SilentlyContinue) {exit 0} else {exit 1}} catch {exit 1}

Get Prereq Commands:

Install-Module -Name AWSPowerShell -Force

Description: Terraform must be installed.

Check Prereq Commands:

terraform --version

Get Prereq Commands:

Write-Host "Terraform is required. Download it from https://www.terraform.io/downloads.html"