Skip to content

T1648 Serverless Execution

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).4 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 to a serverless cloud function, which may then be able to perform actions the original user cannot.56

Serverless functions can also be invoked in response to cloud events (i.e. Event Triggered Execution), potentially enabling persistent execution over time. For example, in AWS environments, an adversary may create a Lambda function that automatically adds Additional Cloud Credentials to a user and a corresponding CloudWatch events rule that invokes that function whenever a new user is created.2 Similarly, an adversary may create a Power Automate workflow in Office 365 environments that forwards all emails a user receives or creates anonymous sharing links whenever a user is granted access to a document in SharePoint.31

Item Value
ID T1648
Sub-techniques
Tactics TA0002
Platforms IaaS, Office 365, SaaS
Version 1.0
Created 27 May 2022
Last Modified 24 October 2022

Mitigations

ID Mitigation Description
M1018 User Account Management Remove permissions to create, modify, or run serverless resources from users that do not explicitly require them.

Detection

ID Data Source Data Component
DS0015 Application Log Application Log Content
DS0025 Cloud Service Cloud Service Modification

References