Synopsis
Activation Period |
14 Days |
Training Period |
30 Days |
Test Period |
N/A (single event) |
Deduplication Period |
1 Day |
Required Data |
|
Detection Modules |
Identity Threat Module |
Detector Tags |
|
ATT&CK Tactic |
|
ATT&CK Technique |
|
Severity |
Informational |
Description
A user configured an Exchange inbox forwarding rule, which forwards emails that meet specific conditions.
Attacker's Goals
Create an inbox rule using a compromised user account to automatically forward emails containing specific conditions to an external recipient.
Investigative actions
- Check what conditions are met in the inbox rule (e.g. specific keywords in the subject or body).
- Determine if any of the conditions and keywords look suspicious.
- Look for signs that the user account and mailbox are compromised (e.g. abnormal logins, unusual activity).
- Check if the forwarding domain is an unknown external domain and look up its reputation.
- Investigate the IP address associated with the rule.
- Follow further actions done by the account.
- Check for a possible phishing campaign on the organization.
- Look for emails sent to this recipient by other users.
Variations
Exchange inbox forwarding rule configured by a delegate userSuspicious Exchange inbox forwarding rule configured
External Exchange inbox forwarding rule configured