Back to results

Suspicious access of BEC related documents in AWS S3 buckets

This query looks for users with suspicious spikes in the number of files accessed that relate to topics commonly accessed as part of Business Email Compromise (BEC) attacks. The query looks for access to files in AWS…

Description

This query looks for users with suspicious spikes in the number of files accessed that relate to topics commonly accessed as part of Business Email Compromise (BEC) attacks. The query looks for access to files in AWS S3 storage that relate to topics such as invoices or payments, and then looks for users accessing these files in significantly higher numbers than in the previous 14 days. Incidents raised by this analytic should be investigated to see if the user accessing these files should be accessing them, and if the volume they accessed them at was related to a legitimate business need. This query contains thresholds to reduce the chance of false positives, these can be adjusted to suit individual environments. In addition false positives could be generated by legitimate, scheduled actions that occur less often than every 14 days, additional exclusions can be added for these actions on username or IP address entities.

Detection logic

Detection requirements

Platform
IaaSOffice SuiteSaaS

The rule states no platform. This is derived from the ATT&CK technique it maps to.

Log source product
aws
Log source service
awscloudtrail

Detections can measure how the public catalogue is used — which detections people look for, and which pages bring them here. It sets a cookie that recognises this browser for 180 days. It is never linked to an account and never follows you to other sites. Privacy notice