The several measures used to safeguard and protect email communication and infrastructure are called email hardening.
This can involve adding encryption, authentication, and spam filtering to prevent unwanted access and guard against risks like phishing assaults and malware.
Email hardening is critical since email is frequently the primary method of communication for both individuals and companies, and it is subject to various cyber-attacks. It is feasible to dramatically minimize the risk of these threats and secure sensitive information by taking actions to harden email systems.
Why is email hardening crucial and acts as an asset to daily communication?
Email hardening is necessary because email is a key medium for communication and cooperation in both personal and business settings. It is an attractive target for hackers since it is used to trade information, commercial transactions, and transmit sensitive data. Without effective security measures in place, email systems and the information contained inside them are exposed to a variety of dangers, including:
1. Spam and phishing: Assaults are false emails intended to deceive users into disclosing personal information or downloading malware.
2. Malware: Malicious software that may be sent over email and used to gain unauthorized access to networks, steal data, or disrupt operations.
3. Unauthorized access: Attackers who obtain access to accounts through weak passwords or other weaknesses can undermine email systems.
4. Security breaches: occur when sensitive information provided by email is intercepted and accessed by multiple persons, resulting in data breaches and the possibility of identity theft or other harm.
To counter these attacks and secure email systems, several email hardening procedures must be implemented. Among the most prevalent practices are:
1. Encryption: Quantitative techniques to encrypt data sent by email, rendering it unreadable to anybody who does not have the right decryption key. Encryption can aid in the prevention of data breaches and illegal access.
2. Authentication: Authenticating the sender and destination of an email to guarantee that only authorized personnel have access to the content. This may be achieved by employing mechanisms such as two-factor authentication and digital signatures.
3. Spam filtering: The use of software to detect and prevent spam and phishing emails before they reach the inbox of the receiver.
4. Network security: Making sure that email systems are secured by firewalls and other security measures can help prevent unwanted access and lower the chance of malware attacks.
5. Employee education: Informing staff on cyber hazards and best practices for securing email systems will help avert mishaps.
Overall, email hardening is crucial because it protects both persons and companies against cyber threats and the catastrophic economic consequences of email-based assaults.
It is conceivable to considerably decrease the danger of email-based attacks and secure sensitive information by deploying suitable security measures and remaining attentive.
Step 1: Begin by monitoring.
It may appear to be a straightforward question, but the sources of email rapidly expand as a business grows. It’s more than simply the email you send from your email client. Consider bills delivered via your accounting software, newsletters from a service like Mailchimp, and customer support from a service like Zendesk. All of these providers send emails on your domain’s behalf. There are less visible sources as well, such as automatic crash reports from your servers or your customer portal, which sends transactional emails such as password reset emails. That long-forgotten SaaS platform you put up may still be sending emails on your behalf.
Any of these might be misconfigured, affecting your domain reputation to the point that a recipient cannot reliably tell whether an email is valid or not.
It is possible to monitor all emails sent on your domain’s behalf. DMARC, an email security standard, allows you to request that receivers all over the globe give reports on emails received from your domain. These reports will provide you with useful information such as which services are sending the emails, which services are receiving them, and if the emails were accepted or refused based on the SPF and DKIM security standards.
A DMARC report aggregator service, such as Mailhardener, is then used to combine those numerous reports into an overview of which services are sending emails and how the receivers processed them.
Hardening Step 1: Use a DMARC aggregator service to monitor the email traffic from your domain.
Step 2: Use SPF to authorize your senders.
One of the first anti-spam and anti-fraud methods was an email protocol enhancement known as the sender policy framework or SPF for short. SPF enables a domain owner to set a policy governing which services may send emails on behalf of the domain.
SPF policies are published as DNS records under the domain used in the sender address. A receiving email system will look for the DNS record and use it to assess if the sender was authorized to send an email on behalf of the domain.
The recipient will consider the email with additional caution, apply harsher spam detection, or possibly reject it entirely if the sender is not on the SPF list. The receiver has a solid indicator that the email is likely real if the sender passes SPF inspection.
SPF breaks with forwarding services
SPF validation can break when the email is being forwarded by a forwarding service.
For example: if old company.com re-brands itself as newcompany.com, it usually set up a forwarding service so that all email received on oldcompany.com is automatically forwarded to newcompany.com. Naturally, they want to keep the original sender’s address when the email is forwarded. So when you send an email from yourdomain.com to olddomain.com it will be forwarded to newdomain.com.
This is a completely legitimate use case, but this also means that olddomain.com just sent an email on behalf of yourdomain.com by forwarding it.
Step 3: Use DKIM to sign all emails.
Because of SPF’s limitations, a second strategy for preventing spam and fraudulent email was developed under the fairly technical moniker DomainKeys Identified Mail, or simply DKIM.
Email is signed with a digital signature using DKIM. This signature demonstrates that the email is genuine (unaltered) and that the sender is permitted to send the email on the domain’s behalf.
The public key for the signature must be added as a DNS entry under your domain in order to utilize DKIM properly. You are telling the recipient to believe the sender if the DKIM signature matches this key by doing.
DKIM is completely optional, therefore the recipient may still accept emails without a DKIM signature. However, when it comes to spam and fraud detection, an email containing an (aligned) DKIM signature provides the recipient more assurance.
Email providers’ ability to self-sign the DKIM signature, which means that the DKIM public key is hosted in their domain rather than yours, is a problem with DKIM. The DKIM public key must be published under the same domain as the sender’s email address for a DKIM signature to be considered aligned in the context of email hardening. The recipient may still verify authenticity with an unaligned signature (the email hasn’t changed since it was delivered), but not authorization.
Be aware that most email services (such as Gmail, Outlook, and Yahoo) will report a DKIM inspection as passed, even if the DKIM signature isn’t aligned. To make sure that all your email is signed and aligned, use DMARC monitoring.
High confidence that the sender is authorized to send an email on behalf of the domain. Email is also authentic.
The email is authentic, but the sender may not be authorized to send an email on behalf of the domain
The receiver does not use DKIM (a ‘neutral’ pass), which can result in false positives and false negatives in spam/fraud detection
High confidence that the email is not authentic, the higher chance of the sender not being authenticated. The receiver may reject the email, or pass it with a high fraud/spam rating
Hardening Step 3: Confirm that all your email services are DKIM aligned.
Step 4: Deploy a DMARC policy
Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an email standard that makes it possible to advise receivers on how to treat email from your domain. DMARC also makes it possible to ask receivers to send reports on the SPF and DKIM inspection results of emails they received from your domain. This is the reporting that we have discussed in step 1.
DMARC is, like SPF, a policy that you publish as a DNS record under your domain. You use DMARC to advise receivers to expect SPF and/or DKIM alignment for all emails from your domain, and what to do if the email does not pass alignment.
The most significant value in a DMARC record is the p (policy) value. It advises the receiver on what to do if an email results in neither an aligned SPF pass nor an aligned DKIM pass. Note that unaligned SPF or DKIM passes do not count toward a DMARC pass.
Email hardening is a vital step in reducing the threat surface of email and protecting against fraudulent activity. By setting up DMARC monitoring, adjusting the settings of email-sending services to achieve SPF and DKIM alignment, and switching the DMARC policy to “p=quarantine” or “p=reject,” it is possible to make it much harder for fraudulent emails to be sent using your domain name. These steps can also improve deliverability and reduce the chances of your emails being flagged as spam. In summary, the key steps to email hardening include setting up DMARC monitoring, achieving SPF and DKIM alignment, and adjusting the DMARC policy.
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