DKIM
DKIM replay attacks are one of the new big things lately, and they work like this: Take a DKIM signed email message, and re-send it to a billion other people. Maybe add another header (or change the subject, if the signature doesn’t cover the subject), or maybe change nothing. Just take that message and randomly spam a million people. The mail will pass DKIM authentication checks, as long as it is sufficiently unchanged, and thus it authenticates as if it were a legitimate email message. Even if you weren’t the original intended recipient. Even if it was sent only to one person but then recent to a million other people, just to annoy them. That’s not a good thing — it can damage a sender’s domain reputation, because people unhappy about that unwanted mail will report it as spam, and spam reporting processing mechanisms will tie it back to the
DELIVTERMS: The (almost) weekly series here on Spam Resource that defines deliverability terminology. Today, I’m going to talk about DomainKeys Identified Mail (DKIM).What is DKIM? DomainKeys Identified Mail (DKIM) is an email authentication protocol. It is one of two different types of email authentication, the other being known as Sender Policy Framework (SPF). It uses a public/private key pair to generate a cryptographic signature for an email message, and the signature information is stored in a hidden “DKIM Signature” email header. The signature allows a receiving mail server to confirm that the message body (and various email headers) were not modified (that is to say, this is truly what was sent by the sender), and they also effectively identify the sender, when the domain name of the sender is the domain name used in the signature.A public/private key pair involves both a private key, which is a bit of information
Jennifer Nespola Lantz does it again! Last time it was a deep dive into the topic of IP warming, this time around it is everything you need to know about email authentication technology (and related bits), covering SPF, DKIM, DMARC and BIMI!Click on through for the first in the series (An Introduction to Email Authentication), and you’ll find links right there that can take you to the rest of the posts in the series. Or, if you’re looking to jump directly to a specific article, here you go:Part 1: Why Email Authentication Matters to Your Email ProgramPart 2: Understanding SPF AuthenticationPart 3: Understanding DKIM AuthenticationPart 4: Understanding DMARC AuthenticationPart 5: Understanding BIMI
DKIM Troubleshooting Guide March 29, 2022 Posted by: Nicola Selenu Category: DKIM , Email Authentication , GUIDES , No Comments Intro to the DKIM Troubleshooting Guide What is DKIM DKIM (Domain Keys Identified Mail) is an email authentication technique that allows the receiver to check that an email was indeed sent and authorized by the […]
There are several causes for DMARC failure. To ensure your emails are properly authenticated and your domain is protected from cybercrime such as spoofing, it’s critical to understand what caused DMARC to fail authentication. When it comes to cyber-attacks, 2021 has shown how unprepared businesses all over the world are. Although Google tries its best to block over 100 million spam messages every day, companies have lost millions of dollars in financial losses due to cybercrime. Spam comes in all shapes and sizes, so why are we so concerned about DMARC email authentication? 94% of all malware is downloaded to a computer via email, and the majority of people are not able to distinguish between a well-crafted phishing email and legitimate messages. DMARC, along with SPF and DKIM, helps you monitor who is sending messages from your email domain and protects your customers from phishing, spoofing, and other email scams. As…
There are several causes for DMARC failure. To ensure your emails are properly authenticated and your domain is protected from cybercrime such as spoofing, it’s critical to understand what caused DMARC to fail authentication. When it comes to cyber-attacks, 2021 has shown how unprepared businesses all over the world are. Although Google tries its best to block over 100 million spam messages every day, companies have lost millions of dollars in financial losses due to cybercrime. Spam comes in all shapes and sizes, so why are we so concerned about DMARC email authentication? 94% of all malware is downloaded to a computer via email, and the majority of people are not able to distinguish between a well-crafted phishing email and legitimate messages. DMARC, along with SPF and DKIM, helps you monitor who is sending messages from your email domain and protects your customers from phishing, spoofing, and other email scams. As
Email spoofing and phishing increased by 220% in 2021. With such high numbers, cyber-criminals are taking advantage of opportunities to spoof emails and phish for valuable information and credentials. As a result, the average cost of a data breach in 2021 was $4.24 million! Types of Spoofing There are many ways cybercriminals can attempt to steal your personal information. These are 8 types of spoofing: Email Spoofing When a malicious sender forges email headers to commit email fraud by faking a sender’s email address. Email spoofing turns into a phishing attack when the hacker embeds the spoofed email with malicious links or an attachment that can install malware onto the recipient’s computer. Caller ID Spoofing When a caller attempts to disguise their identity by falsifying the phone number sent to your caller ID screen during phone calls. They use these spam calls to try and trick you into giving away confidential…
Email marketing has been a staple in internet marketing. Despite this tough pandemic, marketers have developed new email marketing trends to help businesses continue to generate revenue with their email programs. This article shows you the latest email marketing trends that will assist you in making an impact in your email marketing efforts in 2022. Companies have tried their best to make adjustments during this pandemic. They have had to rethink and restructure everything that comes with running a business, developing an email marketing strategy to connect with their customers, as well as, running successful email campaigns. So, what is the best way to recover from this epidemic and stay ahead of your competition? Digital marketing is the answer! Learn these top marketing trends for 2022 to show you how email marketing can help you attract email clients that will lead your business to success. Read along as we dive…
I’ve blogged about using OpenDKIM with Postfix, having myself run the two together for a quite a number of years now. I’ve set up enough servers from scratch to have compiled my own setup guide. You’d find it cryptic and confusing, so I won’t share it. But what I can share instead is this wonderful guide from EasyDMARC that explains how to configure OpenDKIM to add DKIM support to your Postfix install. I’m so glad they put this all together, and if you’re the right type of email nerd, or want to become one, this is something that you will want to bookmark. Read it here.
How do I use OpenDKIM with multiple domain names on a single postfix server? That’s a question I myself had when I first set up my current VPS to host my current email system. So I searched around a bit. I found this guide, but it’s kind of a pain in the rear. Too much heavy lifting.So I tried this instead. It’s a bit of a hacker trick nobody seems to mention online: In your opendkim.conf file, where you specify the domain, you can just include multiple domains here, separated by commas.Instead ofdomain example.comJust putdomain example.com,example.org,mydomain3.comIn your opendkim.conf file.Upside: Super easy.Downside: All domains have to share the same DKIM key, because there’s only one DKIM key setting in opendkim.conf.It works fine. Though you specify the domain name when creating a DKIM key, there’s nothing in the key that is actually domain-specific. At scale, this is insecure. At the hobbyist level, where…