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If you receive an email that looks like it's from one of your friends, just beware! It's possible that the email has been sent by someone else in an attempt to compromise your system. A security researcher has discovered a collection of vulnerabilities in more than 30 popular email client applications that could allow anyone to send spoofed emails bypassing anti-spoofing mechanisms. Discovered by security researcher Sabri Haddouche, the set of vulnerabilities, dubbed MailSploit, affects Apple Mail (macOS, iOS, and watchOS), Mozilla Thunderbird, several Microsoft email clients, Yahoo Mail, ProtonMail, and others. Although most of these affected email client applications have implemented anti-spoofing mechanisms, such as DKIM and DMARC, MailSploit takes advantage of the way email clients and web interfaces parse "From" header. Email spoofing is an old-school technique, but it works well, allowing someone to modify email headers and send an email with the forged sender address to trick recipients into believing they are receiving that email from a specific person. In a dedicated website went up today, Haddouche explained how the lack of input sanitization implemented by vulnerable email clients could lead to email spoofing attack—without actually exploiting any flaw in DMARC. To demonstrate this attack, Haddouche created a payload by encoding non-ASCII characters inside the email headers, successfully sending a spoofed email from an official address belonging to President of the United States. "Using a combination of control characters such as new lines or null-byte, it can result in hiding or removing the domain part of the original email," Haddouche says in his blog post. "We've seen a lot of malware spreading via emails, relying on social engineering techniques to convince users to open unsafe attachments, or click on phishing links. The rise of ransomware distributed over email clearly demonstrates the effectivity of those mechanisms." Besides spoofing, the researcher found some of the email clients, including Hushmail, Open Mailbox, Spark, and Airmail, are also vulnerable to cross-site scripting (XSS) vulnerabilities, which stems from the email spoofing issue. Haddouche reported this spoofing bug to 33 different client applications, 8 of which have already patched this issue in their products before the public disclosure and 12 are on their way to fix it. Here you can find the list of all email and web clients (both patched and unpatched) that are vulnerable to MailSploit attack. However, Mozilla and Opera consider this bug to be a server-side issue and will not be releasing any patch. Mailbird closed the ticket without responding to the issue, while remaining 12 vendors did not yet comment on the researcher's report. Via thehackernews.com

DMARC - What is it? DMARC, which stands for "Domain-based Message Authentication, Reporting & Conformance", is a technical specification created by a group of organizations that want to help reduce the potential for email-based abuse by solving a couple of long-standing operational, deployment, and reporting issues related to email authentication protocols. DMARC standardizes how email receivers perform email authentication using the well-known SPF and DKIM mechanisms. This means that senders will experience consistent authentication results for their messages at AOL, Gmail, Hotmail, Yahoo! and any other email receiver implementing DMARC. We hope this will encourage senders to more broadly authenticate their outbound email which can make email a more reliable way to communicate. Why is DMARC Important? With the rise of the social internet and the ubiquity of e-commerce, spammers and phishers have a tremendous financial incentive to compromise user accounts, enabling theft of passwords, bank accounts, credit cards, and more. Email is easy to spoof and criminals have found spoofing to be a proven way to exploit user trust of well-known brands. Simply inserting the logo of a well known brand into an email gives it instant legitimacy with many users. Users can't tell a real message from a fake one, and large mailbox providers have to make very difficult (and frequently incorrect) choices about which messages to deliver and which ones might harm users. Senders remain largely unaware of problems with their authentication practices because there's no scalable way for them to indicate they want feedback and where it should be sent. Those attempting new SPF and DKIM deployment proceed very slowly and cautiously because the lack of feedback also means they have no good way to monitor progress and debug problems. DMARC addresses these issues, helping email senders and receivers work together to better secure emails, protecting users and brands from painfully costly abuse. How Does DMARC Work? A DMARC policy allows a sender to indicate that their emails are protected by SPF and/or DKIM, and tells a receiver what to do if neither of those authentication methods passes - such as junk or reject the message. DMARC removes guesswork from the receiver's handling of these failed messages, limiting or eliminating the user's exposure to potentially fraudulent & harmful messages. DMARC also provides a way for the email receiver to report back to the sender about messages that pass and/or fail DMARC evaluation. Who Can Use DMARC? DMARC policies are published in the public Domain Name System (DNS), and available to everyone. Because the specification is available with no licensing or similar restriction, any interested party is free to implement it. Source: DMARC.org - Domain-based Message Authentication, Reporting and Conformance