Suspicious objects encryption in an AWS bucket

Cortex XDR Analytics Alert Reference by Alert name

Product
Cortex XDR
Last date published
2024-06-04
Category
Analytics Alert Reference
Order
Alert name

Synopsis

Activation Period

14 Days

Training Period

30 Days

Test Period

1 Hour

Deduplication Period

1 Day

Required Data

  • Requires:
    • AWS Audit Log

Detection Modules

Cloud

ATT&CK Tactic

Impact (TA0040)

ATT&CK Technique

Data Encrypted for Impact (T1486)

Severity

High

Description

An AWS KMS key from a non-organization owned account was used to encrypt multiple objects in the bucket for the first time.
This may indicate an attacker's attempt to perform a ransomware attack against the organization's cloud environment.

Attacker's Goals

  • Gain monetary compensation in exchange for decryption or the decryption key.
  • Permanently deny access to important storage objects.

Investigative actions

  • Check if the external KMS service is a legit encryption service.
  • Check if the identity performed enumeration activity to detect insecure s3 buckets, which are configured without the versioning and MFA Delete mechanisms.
  • Detect additional buckets that were encrypted using the same external KMS service.
  • Disable the identity from which the external service was configured.
  • Enable versioning on every critical bucket.
  • Enable MFA Delete on every critical bucket.