What are the implications of the new SMTP smuggling technique?

Marketer from Email Geeks explains that SMTP smuggling is an implementation issue, not a protocol issue.

Email marketer from TheHackerNews explains that attackers are using SMTP smuggling to bypass traditional email security measures, such as SPF, DKIM, and DMARC, by manipulating the way email servers interpret message boundaries and headers.

Marketer from Email Geeks mentions that ARC is too much of a "Trust me, I checked" system and it's already a potential avenue for abuse.

Marketer from Email Geeks explains that SMTP smuggling is not an SMTP issue, but an issue of security and authorization. They argue that if an inbound system allows anyone to send as "admin@google.com," that's the core problem.

Email marketer from IT Security News details that attackers are exploiting SMTP smuggling vulnerabilities to inject malicious content into email streams, allowing them to bypass security measures and deliver phishing attacks, spam, or malware.

Email marketer from Slashdot user TechSavvy shares the opinion that SMTP smuggling underscores the need for more robust email security measures, including stricter adherence to standards and better validation of message headers.

Email marketer from BleepingComputer details that the SMTP smuggling technique involves inserting malicious content into email headers and bodies in a way that recipient servers interpret as separate, legitimate emails. This can be used for phishing, spam, and malware distribution.

Email marketer from Ars Technica explains that SMTP smuggling exploits weaknesses in the underlying email infrastructure, allowing attackers to inject malicious content while bypassing standard security protocols.

Email marketer from Reddit user u/email_expert shares that the real-world impact of SMTP smuggling includes increased phishing attacks, as attackers can spoof legitimate email addresses to trick users into divulging sensitive information or downloading malware.

Email marketer from SecurityWeek shares that Microsoft patched an SMTP smuggling vulnerability in its email servers. This flaw could be exploited to bypass security checks like SPF, DKIM, and DMARC, allowing attackers to send malicious emails that appear legitimate.

Email marketer from StackOverflow user SMTPGuru shares that SMTP smuggling exploits vulnerabilities in how email servers handle specific message formatting, allowing malicious content to be injected and processed as legitimate email.

Expert from Email Geeks shares that it will be interesting to see how many legit emails fail when folks start requiring compliance with the SMTP spec.

Expert from Email Geeks shares that after 20 years, it might be time to rethink authentication from the ground up due to issues that were previously dismissed.

Expert from Spam Resource explains that preventing SMTP smuggling involves rigorous input validation, strict adherence to SMTP standards, and implementing security measures to prevent unauthorized message injection.

Expert from Word to the Wise answers that to safeguard email streams against SMTP smuggling, organizations should implement strong authentication, encryption, and regular security audits to identify and patch vulnerabilities.

Documentation from RFC Editor explains that the SMTP protocol defines how email messages should be transmitted. Deviations from the standard can lead to vulnerabilities such as SMTP smuggling, where attackers manipulate message formatting to bypass security filters.

Documentation from IETF explains that the SMTP standards are complex, and variations in implementation across different email servers can create opportunities for attackers to exploit vulnerabilities like SMTP smuggling.

Documentation from Microsoft details that Exchange Online Protection (EOP) has been updated to mitigate SMTP smuggling attacks by implementing stricter header validation and message parsing. This helps prevent attackers from exploiting the vulnerability.

Documentation from DMARC.org explains that SMTP smuggling can bypass DMARC because the attack manipulates the email headers in a way that makes the email appear to originate from a legitimate source, even if it doesn't. This undermines DMARC's ability to authenticate the sender.

Documentation from NIST explains that SMTP smuggling poses a significant risk to email security by enabling attackers to bypass authentication protocols and deliver malicious content, potentially leading to data breaches and financial losses.