The cybersecurity industry is faced with the tremendous challenge of analyzing growing volumes of security data in a dynamic threat landscape with evolving adversary behaviors. Today’s security data is heterogeneous, including logs and alerts, and often comes from more than one cloud platform. In order to better analyze that data, we’re excited to announce the release of the Cloud Analytics project by the MITRE Engenuity Center for Threat-Informed Defense, and sponsored by Google Cloud and several other industry collaborators.
Since 2021, Google Cloud has partnered with the Center to help level the playing field for everyone in the cybersecurity community by developing open-source security analytics. Earlier this year, we introduced Community Security Analytics (CSA) in collaboration with the Center to provide pre-built and customizable queries to help detect threats to your workloads and to audit your cloud usage. The Cloud Analytics project is designed to complement CSA.
The Cloud Analytics project includes a foundational set of detection analytics for key tactics, techniques and procedures (TTPs) implemented as vendor-agnostic Sigma rules, along with their adversary emulation plans implemented with CALDERA framework. Here’s a overview of Cloud Analytics project, how it complements Google Cloud’s CSA to benefit threat hunters, and how they both embrace Autonomic Security Operations principles like automation and toil reduction (adopted from SRE) in order to advance the state of threat detection development and continuous detection and response (CD/CR).
Both CSA and the Cloud Analytics project are community-driven security analytics resources. You can customize and extend the provided queries, but they take a more do-it-yourself approach—you’re expected to regularly evaluate and tune them to fit your own requirements in terms of threat detection sensitivity and accuracy. For managed threat detection and prevention, check out Security Command Center Premium’s realtime and continuously updated threat detection services including Event Threat Detection, Container Threat Detection, and Virtual Machine Threat Detection. Security Command Center Premium also provides managed misconfiguration and vulnerability detection with Security Health Analytics and Web Security Scanner.
Cloud Analytics vs Community Security Analytics
Similar to CSA, Cloud Analytics can help lower the barrier for threat hunters and detection engineers to create cloud-specific security analytics. Security analytics is complex because it requires:
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Deep knowledge of diverse security signals (logs, alerts) from different cloud providers along with their specific schemas;
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Familiarity with adversary behaviors in cloud environments;
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Ability to emulate such adversarial activity on cloud platforms;
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Achieving high accuracy in threat detection with low false positives, to avoid alert fatigue and overwhelming your SOC team.
The following table summarizes the key differences between Cloud Analytics and CSA:
Together, CSA and Cloud Analytics can help you maximize your coverage of the MITRE ATT&CK® framework, while giving you the choice of detection language and analytics engine to use. Given the mapping to TTPs, some of these rules by CSA and Cloud Analytics overlap. However, Cloud Analytics queries are implemented as Sigma rules which can be translated to vendor-specific queries such as Chronicle, Elasticsearch, or Splunk using Sigma CLI or third party-supported uncoder.io, which offers a user interface for query conversion. On the other hand, CSA queries are implemented as YARA-L rules (for Chronicle) and SQL queries (for BigQuery and now Log Analytics). The latter could be manually adapted to specific analytics engines due to the universal nature of SQL.
Getting started with Cloud Analytics
To get started with the Cloud Analytics project, head over to the GitHub repo to view the latest set of Sigma rules, the associated adversary emulation plan to automatically trigger these rules, and a development blueprint on how to create new Sigma rules based on lessons learned from this project.
The following is a list of Google Cloud-specific Sigma rules (and their associated TTPs) provided in this initial release; use these as examples to author new ones covering more TTPs.
Sigma rule example
Using the canonical use case of detecting when a storage bucket is modified to be publicly accessible, here’s an example Sigma rule (copied below and redacted for brevity):
The rule specifies the log source (gcp.audit), the log criteria (storage.googleapis.com service and storage.setIamPermissions method) and the keywords to look for (allUsers, ADD) signaling that a role was granted to all users over a given bucket. To learn more about Sigma syntax, refer to public Sigma docs.
However, there could still be false positives such as a Cloud Storage bucket made public for a legitimate reason like publishing static assets for a public website. To avoid alert fatigue and reduce toil on your SOC team, you could build more sophisticated detections based on multiple individual Sigma rules using Sigma Correlations.
Using our example, let’s refine the accuracy of this detection by correlating it with another pre-built Sigma rule which detects when a new user identity is added to a privileged group. Such privilege escalation likely occurred before the adversary gained permission to modify access of the Cloud Storage bucket. Cloud Analytics provides an example of such correlation Sigma rule chaining these two separate events.
What’s next
The Cloud Analytics project aims to make cloud-based threat detection development easier while also consolidating collective findings from real-world deployments. In order to scale the development of high-quality threat detections with minimum false positives, CSA and Cloud Analytics promote an agile development approach for building these analytics, where rules are expected to be continuously tuned and evaluated.
We look forward to wider industry collaboration and community contributions (from rules consumers, designers, builders, and testers) to refine existing rules and develop new ones, along with associated adversary emulations in order to raise the bar for minimum self-service security visibility and analytics for everyone.
Acknowledgements
We’d like to thank our industry partners and acknowledge several individuals across both Google Cloud and the Center for Threat-Informed Defense for making this research project possible:
– Desiree Beck, Principal Cyber Operations Engineer, MITRE
– Michael Butt, Lead Offensive Security Engineer, MITRE
– Iman Ghanizada, Head of Autonomic Security Operations, Google Cloud
– Anton Chuvakin, Senior Staff, Office of the CISO, Google Cloud