Isai
1c59a6adde
* [Rule Tuning] Potential AWS S3 Bucket Ransomware Note Uploaded This rule was very loud in telemetry since it's last tuning. ~8,938 alerts in last 24 hours. All false positives due to regex pattern matches for file names like `enc` as part of /filetransfertmsadherence/ and absence/; `lock` as part of citations-blocks/. I've reworked this rule based on more research into common ransom note file name keywords and replaced the list here with the most common keywords. For `file` (the most common) and `back`, I was still seeing false positives so decided to alert on a combination of either or these 2 words in conjunction with any of the other words from the list. I also changed the regex to be case-insensitive. With this new query, I see only true positive results within the last year all from known testing events. I changed the toml file name so the rule looks new but it is just tuned. I've updated the description and investigation guide, and added the study I used as a reference: https://www.mdpi.com/2073-431X/10/11/145#computers-10-00145-f002 Test data is in our stack, script for executing is here: Screenshot of new working query in our test stack * Apply suggestions from code review * removing redundany regex pattern
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 |