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).(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 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), 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.(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)
Procedure Examples |
|
| Name | Description |
|---|---|
| Pacu |
Pacu can create malicious Lambda functions.(Citation: GitHub Pacu) |
Mitigations |
|
| Mitigation | Description |
|---|---|
| Account Use Policies |
Configure features related to account use like login attempt lockouts, specific login times, etc. |
| User Account Management |
Manage the creation, modification, use, and permissions associated to user accounts. |
References
- Rhino Security Labs. (2019, August 22). Pacu. Retrieved October 17, 2019.
- Spencer Gietzen. (n.d.). Privilege Escalation in Google Cloud Platform – Part 1 (IAM). Retrieved May 27, 2022.
- Rhino Security Labs. (n.d.). AWS IAM Privilege Escalation – Methods and Mitigation. Retrieved May 27, 2022.
- Matt Muir. (2022, April 6). Cado Discovers Denonia: The First Malware Specifically Targeting Lambda. Retrieved May 27, 2022.
- L'Hutereau Arnaud. (n.d.). Google Workspace Malicious App Script analysis. Retrieved October 2, 2024.
- HackTricks Cloud. (n.d.). GWS - App Scripts. Retrieved July 1, 2024.
- Eric Saraga. (2022, February 2). Using Power Automate for Covert Data Exfiltration in Microsoft 365. Retrieved May 27, 2022.
- Daniel Grzelak. (2016, July 9). Backdooring an AWS account. Retrieved May 27, 2022.
- Berk Veral. (2020, March 9). Real-life cybercrime stories from DART, the Microsoft Detection and Response Team. Retrieved May 27, 2022.
- Microsoft Developer Support. (2020, May 9). Control Access to Power Apps and Power Automate with Azure AD Conditional Access Policies. Retrieved July 1, 2024.
- Google Workspace. (2024, March 5). Monitor & restrict data access. Retrieved July 1, 2024.
- Microsoft. (2022, February 15). Email exfiltration controls for connectors. Retrieved May 27, 2022.
Связанные риски
Каталоги
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