By Shahzad Subhani | TN Media News: As email remains a vital communication tool, cybercriminals continue to exploit it for malicious purposes. In this article—the second in a series on email security—we outline common types of email attacks and offer practical guidance to help organizations and individuals stay protected.
1. Email Relaying: What It Is: Email relaying occurs when an attacker uses your SMTP server to send emails to other domains without your consent. This used to be common when servers were poorly configured.
Prevention Tips: Configure your server to accept emails only for your domains. Restrict outbound email relay to authorized IP addresses. Limit port 25 access to trusted systems only.
2. Spam and Unwanted Emails:
Definition: Spam includes promotional, marketing, or unwanted emails. Such messages often flood corporate inboxes daily.
Causes: Stolen email addresses, Use of corporate accounts on third-party sites, Excessive graphics or shortened URLs
Prevention Tips: Regularly check for false positives and whitelist trusted senders. Block mailing list sources like Google Groups.
3. Email Malware and Ransomware:
Attack Method: Attackers send executable files or documents with hidden macros via email. These may contain links to malicious websites.
Prevention Tips: Train users not to click unexpected links. Block executable attachments using email gateways. Remove macros from documents through gateway settings like Symantec’s DISARM feature. Disable URLs in email bodies, and add sandboxing where possible.
4. Spoofing and Phishing:
Spoofing Explained: This occurs when attackers forge email addresses to appear legitimate. Often used in Business Email Compromise (BEC) attacks, they trick users into taking harmful actions.
Phishing Tactics: These emails mimic trusted sources and aim to steal personal or financial information.
Prevention Tips: Use DNS validation (SPF, DKIM, DMARC). Reject emails with invalid reverse DNS or mismatched sender domains. Flag emails that fail spoofing checks.
5. Spear Phishing:
Definition: A targeted form of phishing aimed at a specific individual or organization. Attackers often gather personal information to customize their messages.
Risk: Emails from hacked partner organizations can seem authentic, increasing the likelihood of victim engagement.
6. Email Impersonation:
What Happens: Attackers outside your network send emails pretending to be someone from your organization.
Prevention Tips: Use SPF, DKIM, and DMARC to validate outgoing emails. Block or flag emails failing DMARC checks on the receiving end.
7. Email DoS/DDoS Attacks
Overview: Attackers flood your servers with emails, overwhelming the system and blocking legitimate communication.
Prevention Tips: Set limits on concurrent connections and recipients per message.
Define email queue sizes and use IP reputation filtering.
Throttle or block abnormal traffic patterns.
Final Thoughts: Phishing, spoofing, and spam are just a few of the many threats targeting email systems today. With proper configuration, DNS validation, user awareness, and layered security measures, most attacks can be identified and blocked before any damage occurs.
To dive deeper into this topic, you can watch the full video guide on Email Attacks at TNMN.tv.
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