What are signs of an email attack?

The presence of all the listed scenarios indicates potential signs of an email attack.

A sudden increase in advertising and spam emails can suggest that an attacker has compromised an email account or that there has been a phishing attempt. This is often a tactic used to overwhelm users with malicious content and potentially gather sensitive information.

A change in the email template and signature might indicate that an email account has been hacked, leading to unauthorized modifications which can be leveraged in phishing scams to impersonate legitimate users or organizations.

Unavailability of the email server can point to a Distributed Denial of Service (DDoS) attack, where the server is overwhelmed with traffic, preventing legitimate users from accessing email services. This disruption is often an indication of an ongoing attack aimed at taking control of email communications.

In the context of incident response and handling, recognizing a combination of these signs is critical for identifying and mitigating email-based attacks effectively, making the collective understanding of these indicators essential for anybody involved in incident handling.