Introduction: Cloud-Based Infrastructure and Its Forensic Challenges
Large-scale investigations have a wide array of challenges. One that’s increasingly common is navigating the cloud-based infrastructure of large organizations. As more businesses integrate cloud services with on-premises systems like Microsoft Active Directory, attackers can easily move between cloud and on-premises environments—an investigator’s nightmare!
Cloud platforms are tightly woven into corporate IT, yet they bring unique considerations for incident response and forensic investigations. A key point to remember is that cloud infrastructure essentially boils down to “someone else’s computer.” And unfortunately, that “someone else” may not be ready to grant you full forensic access when a breach occurs.
To get into the nitty-gritty of cloud forensics, it’s essential to understand the different types of cloud offerings: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). Each of these comes with unique access levels and data availability, impacting how effectively we can conduct investigations.
Diving Into Cloud Services: IaaS, PaaS, and SaaS
Let’s break down these cloud service types to see how they affect access to forensic data.
1. Infrastructure as a Service (IaaS)
What It Is: In IaaS, cloud providers offer virtual computing resources over the internet. You get to spin up virtual machines and networks, almost like your own data center, except it’s hosted by the provider.
Forensic Access: Since customers manage their own operating systems and applications, IaaS provides the most forensic access among cloud service types. Investigators can perform standard incident response techniques, like log analysis and memory captures, much as they would on on-prem systems.
Challenges: The major challenge is the dependency on the provider. Moving away from a provider you’ve invested in heavily can be a headache. So, it’s essential to plan security and forensic readiness from the start.
2. Platform as a Service (PaaS)
What It Is: PaaS bundles the OS with essential software, such as application servers, allowing you to deploy applications without worrying about the underlying infrastructure.
Forensic Access: This setup limits access to the underlying OS, which restricts what investigators can directly analyze. You can access logs and some application data, but full system access is typically off-limits.
Challenges: Because multiple customers often share the infrastructure, in-depth forensics might reveal data belonging to other clients. Therefore, cloud providers rarely allow forensic access to the physical machines in a PaaS setup.
3. Software as a Service (SaaS)
What It Is: SaaS handles everything from the OS up, so the customer only interacts with the software.
Forensic Access: Forensics in a SaaS environment is usually limited to logs, often determined by the service tier (and subscription cost). If a backend compromise occurs, SaaS logs might not give enough data to identify the root cause.
Challenges: This limitation can cause breaches to go unnoticed for extended periods. SaaS providers control everything, so investigators can only work with whatever logs or data the provider makes available.
Cloud-Based Forensics vs. Traditional On-Premises Forensics
With traditional on-premises forensics, investigators have deep access to various system components. They can use techniques like creating super timelines to correlate events across systems, uncovering hidden evidence. Cloud forensics, however, is a different story.
Cloud investigations resemble working with Security Information and Event Management (SIEM) systems in Security Operations Centers (SOCs). Just as SIEM setups depend on pre-selected data inputs, cloud providers offer only certain types of logs and data. This means you need to plan ahead to ensure you’re capturing the right logs. When it’s time to investigate, you’ll be limited to whatever was logged based on the initial setup and your subscription level.
Essential Steps for Incident Response in the Cloud
Handling incidents in the cloud follows many of the same steps as traditional response processes, but there’s an added emphasis on preparation. Without the right preparations, investigators could be left scrambling, unable to detect or respond to intrusions effectively.
Preparation:
Know Your Environment: Document the systems your organization uses, along with any defenses and potential weak spots. Prepare for likely incidents based on your cloud architecture and assets.
Logging: Make sure you’re subscribed to an adequate logging tier to capture the necessary data for investigations. Higher-tier subscriptions often provide more granular logs, which are crucial for in-depth analysis.
Data Retention: Cloud providers offer different retention periods depending on the subscription. Ensure the data you need is available long enough for proper analysis.
Detection:
Use tools like the MITRE ATT&CK® framework to identify techniques and indicators of compromise specific to cloud environments.
Regularly review security logs to detect anomalous activities. Log aggregators and monitoring tools can streamline this process.
Analysis:
For IaaS, you can perform traditional forensic techniques, such as memory analysis and file recovery.
For PaaS and SaaS, focus on analyzing available logs. If suspicious activity is detected, collect and analyze whatever data the provider can provide.
Correlate cloud logs with on-premises logs to trace attacker movements between environments.
Containment & Eradication:
In the cloud, containment often involves disabling specific accounts or access keys, updating permissions, or isolating compromised systems.
For SaaS or PaaS, the provider might handle containment on their end, so you’ll need a strong partnership with your provider to act quickly in a breach.
Recovery:
Implement any necessary changes to strengthen security and avoid re-compromise.
This may involve changing access policies, adjusting logging settings, or reconfiguring cloud resources.
Lessons Learned:
Post-incident, review what happened and how it was handled. Look for opportunities to enhance your response capabilities and bolster your cloud security posture.
Leveraging the MITRE ATT&CK Framework for Cloud Environments
The MITRE ATT&CK framework, renowned for cataloging adversary tactics and techniques, has been expanded to include cloud-specific threats. While current versions focus on major cloud platforms like Microsoft Azure and Google Cloud, they also include techniques applicable to IaaS and SaaS broadly. This makes it a valuable resource for proactive defense planning in cloud environments.
Regularly reviewing the techniques in the framework can help you design detections that fit your organization’s cloud architecture. By integrating the ATT&CK framework into your cloud incident response strategy, you’ll be better equipped to recognize suspicious behavior and quickly respond to emerging threats.
Conclusion: Embracing Cloud Forensics in an Evolving Threat Landscape
Cloud forensics presents a unique set of challenges, but with the right knowledge and tools, your organization can respond effectively to incidents in cloud environments. Remember, it’s all about preparation. Invest in adequate logging, establish incident response protocols, and familiarize your team with the MITRE ATT&CK framework. By doing so, you’ll ensure that you’re ready to tackle threats in the cloud with the same rigor and responsiveness as on-premises investigations.
Akash Patel
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