What is Secure Email Gateway Bypass?

A Secure Email Gateway (SEG) bypass, specifically in the context of an MX (Mail Exchange) bypass, refers to a vulnerability or a method that allows malicious actors to circumvent or evade the protections provided by a Secure Email Gateway. A Secure Email Gateway is a tool or service that helps organizations protect their email systems from various threats such as spam, phishing attacks, malware, and other malicious content. It typically works by inspecting incoming and outgoing email traffic, filtering out potentially harmful messages, and enforcing email security policies. An MX bypass occurs when attackers find a way to deliver malicious emails directly to the recipient's email server without going through the organization's Secure Email Gateway. This can happen due to misconfigurations, vulnerabilities in the email server, or weaknesses in the email infrastructure. When attackers successfully bypass the Secure Email Gateway, they can deliver malicious emails to users' inboxes, increasing the risk of successful phishing attacks, malware infections, data breaches, and other security incidents. Organizations need ensure that their mail servers are locked down to only receive email from the Secure Email Gateways, by allow listing the Gateway's IPs in order to mitigate the risk of bypasses and ensure comprehensive protection against email-based threats.

How can Secure Email Gateway Bypass be Prevented?

Locking down the mail server to only accept email sent via the secure email gateway. Further defense in depth approaches include a good security awareness training plan, to reduce the risk of employee interaction with a malicious email. Companies pay huge amounts for spam filtering solutions, it is highly important to ensure that you have periodic reviews with your email security provider or MSP, and ask them for guarantees that your mail servers are locked down, ensuring that mail always go through your Secure Email Gateway. Stellastra can monitor for such misconfigurations in your own infrastructure and supply chain.

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