What are the best practices for securing email communications against advanced persistent threats?

2 Implement authentication

Authentication is the process of verifying the identity and legitimacy of the sender and the recipient of an email. Authentication can prevent spoofing, impersonation, or domain hijacking attacks that can trick you into opening malicious emails or revealing sensitive information. You can use authentication protocols, such as sender policy framework (SPF), domain keys identified mail (DKIM), or domain-based message authentication, reporting, and conformance (DMARC). SPF checks if the sender's IP address matches the domain's records, DKIM verifies if the email signature matches the domain's public key, and DMARC enforces a policy on how to handle emails that fail SPF or DKIM checks.

3 Apply filtering

Filtering is the process of screening incoming and outgoing emails for spam, malware, or phishing indicators. Filtering can reduce the volume and impact of malicious emails that can compromise your security or productivity. You can use filtering tools, such as spam filters, antivirus software, or email security gateways. Spam filters analyze the email headers, content, and reputation to block or quarantine unwanted or suspicious emails. Antivirus software scans the email attachments and links for malware or viruses and removes or blocks them. Email security gateways inspect the email traffic and apply various security policies and rules to prevent or detect APTs.

4 Educate users

Users are the weakest link in email security, as they can fall victim to social engineering, human error, or negligence. Users can expose themselves or their organizations to APTs by clicking on malicious links, opening infected attachments, or sharing sensitive information. To prevent or mitigate these risks, you need to educate your users on how to recognize and respond to email threats, how to use encryption and authentication tools, and how to follow security policies and best practices. You can provide regular training, awareness campaigns, or simulations to improve your users' security skills and behavior.