GCP - Cloud Functions Post Exploitation

👉 Overview

👀 What ?

Google Cloud Functions Post Exploitation refers to a series of techniques and methods used by an attacker to exploit a Google Cloud Function after gaining initial access. Google Cloud Functions are a serverless execution environment for building and connecting cloud services. With Cloud Functions, you can write simple, single-purpose functions that are attached to events emitted from your cloud infrastructure and services.

🧐 Why ?

Understanding Google Cloud Functions Post Exploitation is of significant importance due to the ever-growing cloud adoption by businesses of all sizes. As more businesses migrate their infrastructure and services to the cloud, the attack surface becomes increasingly wider. Therefore, understanding how an attacker can exploit these services after initial access is vital for both blue teams and red teams. For blue teams, it aids in developing effective detection and prevention strategies. Simultaneously, for red teams, it helps in simulating realistic attack scenarios to test the effectiveness of defense strategies.

⛏️ How ?

GCP Cloud Functions Post Exploitation can be performed in various ways. An attacker who has gained initial access can explore the environment to identify potential weak spots, escalate privileges, or move laterally within the cloud environment. They can manipulate the function to perform actions it wasn't intended to, like exfiltrating data, destabilizing the service, or even deploying malicious software. Implementing defenses against post-exploitation involves monitoring for suspicious activity, hardening the cloud environment, and applying least privilege principles.

⏳ When ?

The practice of exploiting Google Cloud Functions has been on the rise ever since the adoption of cloud services increased. As more businesses started to use GCP and other cloud services, attackers found new ways to exploit these services. Therefore, the need for understanding and mitigating against such attacks became a crucial aspect of cybersecurity.

⚙️ Technical Explanations

Google Cloud Functions (GCF) are event-driven, meaning they respond to HTTP(s) events or published messages from Pub/Sub or Cloud Storage. When an attacker manages to exploit a GCF, they can potentially control the behavior of the function. This could involve altering the function's code, changing its triggers, or even using the function's permissions to access other services within the GCF project. To mitigate against such attacks, organizations should implement a robust IAM policy, regularly audit their functions and associated triggers, and monitor for any unusual activity.