Isai
8eb32f96ce
- changed rule from esql to new_terms. While details are limited in telemetry, the noise is evident. We've also gotten complaints about the noise from our own infosec team, prompting this tuning. Changes to a new terms rule will reduce noise by over 90% when tested against prod data. - This originally only triggered for role chaining within a single AWS account, so excluded common cross-account role assumption. However, I am unable to apply a filter for that with KQL but the benefits to creating new-terms rule outweigh the benefits of keeping that exclusion with esql. - looks for unique combination of `aws.cloudtrail.user_identity.session_context.session_issuer.arn` (originating role) and `aws.cloudtrail.resources.arn`(target role). Because the only identity type we are concerned with here are `AssumedRole` types, we don't have the same new_terms field limitations as with other rules that also must consider `IAMUser` types. So these fields will suffice. - added highlighted fields - added index pattern. rule is compatible with filebeat - updated the investigation guide and description and description Note: I may consider creating a broader BBR rule, with the same criteria just not new terms, as a way of capturing all instances of role chaining for investigative purposes Co-authored-by: Terrance DeJesus <99630311+terrancedejesus@users.noreply.github.com>
rules/
Rules within this folder are organized by solution or platform. The structure is flattened out, because nested file hierarchies are hard to navigate and find what you're looking for. Each directory contains several .toml files, and the primary ATT&CK tactic is included in the file name when it's relevant (i.e. windows/execution_via_compiled_html_file.toml)
| folder | description |
|---|---|
. |
Root directory where rules are stored |
apm/ |
Rules that use Application Performance Monitoring (APM) data sources |
cross-platform/ |
Rules that apply to multiple platforms, such as Windows and Linux |
integrations/ |
Rules organized by Fleet integration |
linux/ |
Rules for Linux or other Unix based operating systems |
macos/ |
Rules for macOS |
ml/ |
Rules that use machine learning jobs (ML) |
network/ |
Rules that use network data sources |
promotions/ |
Rules that promote external alerts into detection engine alerts |
windows/ |
Rules for the Microsoft Windows Operating System |
Integration specific rules are stored in the integrations/ directory:
| folder | integration |
|---|---|
aws/ |
Amazon Web Services (AWS) |
azure/ |
Microsoft Azure |
cyberarkpas/ |
Cyber Ark Privileged Access Security |
endpoint/ |
Elastic Endpoint Security |
gcp/ |
Google Cloud Platform (GCP) |
google_workspace/ |
Google Workspace (formerly GSuite) |
o365/ |
Microsoft Office |
okta/ |
Oka |