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Build a Security Data Lake

A security data lake is an intriguing value proposition. If well-architected, it can lead to a highly cost-efficient and scalable telemetry engine. As organizations become more comfortable storing massive amounts of sensitive data in the public cloud, data gravity increases and renders the nearby compute services for security-centric workloads highly attractive.

However, building security data lake is a non-trivial engineering undertaking. Most detection and response workloads rely on structured data, requiring flexible data collection, parsing, cleaning, normalization. In addition, typical lake interfaces are developer-facing, require SQL knowledge, and data engineering skills—something security experts are insufficiently equipped with.

Nonetheless, those embarking on the journey to build a security data lake ideally know what they are doing. The above diagram shows an architecture with Tenzir acting at the transport layer, as well as supporting various detection, investigation, and response functions.

Key Takeaways
  • A security data lake holds promise for cost-efficient operation and scalable execution of security workloads, such as threat detection, hunting, investigation, and response.
  • Building a security lake is a complex undertaking requiring deep data engineering skills and security domain knowledge.
  • Tenzir complements a security data lake as a highly flexible ETL layer for collection, transformation, and shipping of security telemetry.
  • Tenzir offers numerous operators for data reshaping and normalization to combat the schema diversity that is at odds with the abstractions a data lake provides.
  • Tenzir provides several building blocks for specific security use cases, such as YARA and Sigma executing, or retro matching of indicators, that can run efficiently on top of a data lake.
Terminology: Data Warehouse → Data Lake → Data Lakehouse

Data warehouses are systems primarily for structured data, excelling in decision support and business intelligence applications, with coupled storage and compute, but less suited for unstructured or semi-structured data. Data lakes emerged as repositories for raw data in various formats, including unstructured data; they decouple storage and compute, offering flexibility and scalability but lack critical features like transaction support. Data lakehouses combine the strengths of both, with data warehouse-like structures and management features on top of low-cost cloud storage. They support unstructured and structured data, diverse workloads, and maintain a decoupled architecture while integrating key features of data warehouses. Data lake and lakehouse are often used interchangeably in the context of open-source layers like Delta Lake, Iceberg, and Hudi.

Problem: Skyrocketing security data

The telemetry data from network, endpoints, identity and cloud services keeps growing at a relentless pace. Security teams are faced with the tough challenge to keep up with the volume and diversity of this telemetry, as they need to leverage it for threat detection, hunting, investigation, and response to protect their constituency.

As organizations increasingly shift to public and private cloud offerings to centralize storage and processing needs, the traditional model of working with security data is under scrutiny. Building a security data lake appears attractive to those with data engineering resources.

However, building such a lake is heavy lifting and can fail in many ways. A key challenge is the translation of the complex security use cases to the abstractions provided by a data lake.

Forgetting the security transport layer

Populating a security data lake requires a flexible collection, transformation, and normalization layer to ship the data to the lake. In the above diagram, this is the extract-transform-load (ETL) layer. It has its dual on the output side, called Reverse ETL, to deliver the analytics results into dashboards, create models from data, expose subsets as dynamic APIs, or build (micro) products with the results.

A data lake has enough horse power for storage and analytics, but it does not come with a ETL layer that lifts security data into the desired structured form for ultra-scalable processing. Based on the scope of the lake, this can take up a non-negligible amount of engineering. Building a composable and fast ETL layer is an engineering feat on its own. The significance of this transport layer depends on the diversity and volume of the data that should land in the lake:

For low-volume, low-diversity settings, an ETL layer becomes insignificant. Arguably, the concept of "lake" only makes sense when there is either high-volume or high-diversity data or both. In these cases the transport layer plays a crucial role in the overall architecture.

Generic ETL solutions often lack support for domain-specific types, such as IP addresses, CIDR subnets, or URLs. Moreover, some workloads that do not require global correlation can cheaply run the ETL layer itself.

Wrangling metadata and juggling tables

At their core, data lakes store data typically in columnar form, e.g., Apache Parquet. This raw table format has several limitations that lakehouse metadata layers attempt to fix, such as schema evolution, time travel, partitioning, compaction, and record deletion.

A big part of a lake architecture is that storage and compute are decoupled. When building on top of open at-rest formats, like Parquet, this allows for choice of popular processing engines, e.g., DuckDB, Clickhouse, or polars. The decoupling benefits naturally apply to the highly integrated cloud provider services, which can be operated more cost-efficiently when engineering resources are scarce.

But even with a lake in place, making it security is non-trivial. For example, managing schemas are still hard, despite schema evolution. What a lake provides as abstraction for evolving schema is a monotonically increasing version. This linear time travel feature supports querying data at a given time, but that's not what we want for manual threat hunting and automatic retrospective detection. Instead, we want to query all compatible data. In other words, today's linear schema evolution is not suitable for typical detection and response workloads and requires custom engineering.

Solution: Tenzir as ETL for your Security Data Lake

Tenzir's Security Data Pipelines provide the ETL layer for your lake, taking care of data collection, reshaping, filtering, and normalization. Tenzir Pipelines can write into the cloud native's object storage, e.g., natively supporting writing Parquet files into an S3 bucket.

In addition to highly scalable data ingestion, Tenzir's pipelines support numerous building blocks for security use cases, such as high-performance contextualization with threat intelligence or matching YARA and Sigma rules.

The symmetry in the pipeline architecture also enables a streamlined hand-over from detection to data-driven response, e.g., by writing pipelines that reshape alerts into API calls for blocking user accounts. The SecDataOps principle of data driving use cases is the connective tissue of your security data lake.

The security ETL layer for your data lake

When you are building a security data lake to centralize storage and compute, Tenzir's pipelines complement lake with an ETL and reverse ETL transport layer. The data acquisition framework handles both structured and unstructured data, offering a one-stop solution for your data movement needs:

Tenzir pipelines support unstructured data as raw chunks of bytes and structured data as data frames backed by Apache Arrow record batches. We designed separate mechanisms saving/loading bytes and parsing/printing data frames. In fact, a single pipeline can switch between processing structured and unstructured data, making pipelines a universal vehicle to acquire, transform, and ship data.

The high customizability via plugins supports implementing your own operators, e.g., to deploy machine-learning models for in-band inference, perform feature extraction to obtain word/sentence/graph/image embeddings, or simply integrate a third-party library via C++ or Python.

In summary, Tenzir is much more than just connecting sources and sinks. You get a vehicle for executing security-specific workloads at a location of your choice.

Full control over data normalization

One way to escape the schema wrangling hell is to normalize your telemetry, coercing the data to a specific schema. Tenzir offers operators across the entire spectrum of normalization:

The spectrum begins with parsing data, i.e., moving it from unstructured to structured. Tenzir's ability to apply parsers recursively make it easy, e.g., to parse Syslog that contains JSON, which in turn contains a CEF record. In other words, parsers also work on individual fields to decompose them in their full structure. Most systems stop at renaming fields, e.g., in YAML configuration files, but fall short in supporting structural adaptations that change the nesting or "listness" of individual values. Tenzir also supports changing values and can ultimately validate schemas as well.1

Spatial schema evolution

Another way to alleviate schema wrangling pains is by automating partition/table management. Tenzir performs deep schema-inference for all its parsers (e.g., JSON, CSV) so that you don't have to think of schemas when onboarding data. This comes especially handy when time is of essence, e.g., during incident response engagements or post-breach investigations. Tenzir's catalog tracks schemas and their evolution, but in a spatial instead of temporal (linear) fashion: per-partition sparse indexes allow for quick identification of a relevant subset of tables. Instead of querying a specific table version, you come with an expression that yields a set of candidate partitions to process.

This light-weight catalog is by no means intended to be a replacement for Delta, Iceberg, or Hudi. Rather, it can can complement large-scale analytics for some some highly selective, security-specific workloads, such as retro-matching of indicators of compromise.


Embarking on a Security Data Lake project is quite an engineering feat, but when properly executed, can yield a highly efficient engine for running security workloads. Tenzir complements a lake as a powerful ETL layer, taking care of data collection, reshaping, normalization, and shipping.

Leveraging Tenzir's existing building blocks for detection and response use cases, such as executing YARA and Sigma rules, can further accelerate the development of certain services that run on top of a scalable lake infrastructure. Because Tenzir is built with open data standards, such as Apache Arrow and Parquet, there is a high degree of interoperability with existing solutions from the data ecosystem.


  1. The validate operator is still under development.