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VAST v1.0

· 4 min read
Dominik Lohmann

We are happy to announce VAST v1.0!

This release brings a new approach to software versioning for Tenzir. We laid out the semantics in detail in a new VERSIONING document.

Query events based on their import time​

The new #import_time extractor allows for exporting events based on the time they arrived at VAST. Most of the time, this timestamp is not far away from the timestamp of when the event occurred, but in certain cases the two may deviate substantially, e.g., when ingesting historical events from several years ago.

For example, to export all Suricata alerts that arrived at VAST on New Years Eve as JSON, run this command:

vast export json '#type == "suricata.alert" && #import_time >= 2021-12-31 && #import_time < 2022-01-01'

This differs from the :timestamp type extractor that queries all events that contain a type timestamp, which is an alias for the time type. By convention, the timestamp type represents the event time embedded in the data itself. However, the import time is not part of the event data itself, but rather part of metadata of every batch of events that VAST creates.

Omit null fields in the JSON export​

VAST renders all fields defined in the schema when exporting events as JSON. A common option for many tools that handle JSON is to skip rendering null fields, and the new --omit-nulls option to the JSON export does exactly that.

To use it on a case-by-case basis, add this flag to any JSON export.

vast export json --omit-nulls '<query>'
 
# This also works when attaching to a matcher.
vast matcher attach json --omit-nulls <matcher>

To always enable it, add this to your vast.yaml configuration file:

vast:
  import:
    omit-nulls: true

Selection and Projection Transform Steps​

Transforms → Pipelines

In VAST v2.2, we renamed transforms to pipelines, and transform steps to pipeline operators. This caused several configuration key changes. Please keep this in mind when reading the example below and consult the documentation for the up-to-date syntax.

Reshaping data during import and export is a common use case that VAST now supports. The two new built-in transform steps allow for filtering columns and rows. Filtering columns (projection) takes a list of column names as input, and filtering rows (selection) works with an arbitrary query expression.

Here’s a usage example that sanitizes data leaving VAST during a query. If any string field in an event contains the value tenzir or secret-username, VAST will not include the event in the result set. The example below applies this sanitization only to the events suricata.dns and suricata.http, as defined in the section transform-triggers.

vast:
  # Specify and name our transforms, each of which are a list of configured
  # transform steps. Transform steps are plugins, enabling users to write more
  # complex transformations in native code using C++ and Apache Arrow.
  transforms:
     # Prevent events with certain strings to be exported, e.g., "tenzir" or
     # "secret-username".
     remove-events-with-secrets:
       - select:
           expression: ':string !in ["tenzir", "secret-username"]'
 
  # Specify whether to trigger each transform at server- or client-side, on
  # import or export, and restrict them to a list of event types.
  transform-triggers:
    export:
      # Apply the remove-events-with-secrets transformation server-side on
      # export to the suricata.dns and suricata.http event types.
      - transform: remove-events-with-secrets
        location: server
        events:
          - suricata.dns
          - suricata.http

Threat Bus 2022.01.27​

Thanks to a contribution from Sascha Steinbiss (@satta), Threat Bus only reports failure when transforming a sighting context if the return code of the transforming program indicates failure.

A small peek behind the curtain: We’re building the next generation of Threat Bus as part of VAST. We will continue to develop and maintain Threat Bus and its apps for the time being.

Threat Bus 2022.01.27 is available 👉 here.