por Do you know what the EML format is and why it is important to know its structure in cybersecurity? Email has always been and continues to be the main attack vector that malicious hackers use to reach our systems.. Therefore, they must be rigorously analyzed before being opened or paying attention to the instructions they present to us. Every day, there are hundreds of thousands of attempts to phishingextortion and shipments of malware through these communication channels. Therefore, certain habits and safety measures are required to stay safe.
There are different techniques and tools that you can use to evaluate the content of an email.. In fact, in the second part of this post, we will talk about the protocols necessary to protect the security of these messages. However, first we will focus on knowing the structure of the type of file that is used to send messages and attachments by this popular means. Next, we will explain what is EML format and why it is essential to know how it works to preserve email security.
What is EML format?
The term EML is an acronym for the word email and corresponds to a type of file format that is currently used as a standard for sending emails.. That is, when sending an email by this means, an EML file is sent that can be interpreted by the interface of the email service that we have chosen as users.
The EML format has a three-part structure which, if you use an email account, you will surely recognize instantly:
Headboard– Contains information about the actual origin of the mail, as well as data about the security of the servers used and other important information about the file.Body: has the content of the email and, if it is a forwarding, may contain information about the past senders.Attachments: files attached to the email.
Email analysis
We have already seen what the EML format is and the simple structure that makes it up. Now, we will talk about why it is important to know this type of files when analyzing them in search of malware. Next, we will explain how email analysis is executed, according to each part of its EML structure.
Header analysis
The header, as we explained before, presents information about the origin of the email. To ensure that this data is true, The following protection protocols must be used:
SPF: Sender Policy Framework is an email security protocol that allows you to verify the origin servers of the message. In this way, any email that comes from servers that are not properly certified is not accepted.DKIM: Domain Keys Identified Mail is a digital signature protocol that guarantees one hundred percent the integrity and authenticity of email. These digital signatures serve to ensure that the sender of the email is who they say they are and, furthermore, that the content of the email is intact.DMARC: Domain-based Message Authentication, Reporting & Conformance is a protocol that verifies that the previous two have been fulfilled correctly. If any of them cannot be verified, reject or report the email.
The Headboard contains relevant information for the analyst such as:
Source Server IP.Source Server Domain.Sender.Reply Address.
Body analysis
Although a common user does not know what the EML format is, it is necessary to learn how to analyze the body of the same in search of:
Suspicious URLs.Text content: check if it contains anomalies or errors in writing, spelling, tone or lexicon.Possible senders and emails if it is a forwarding.
Attachment Scanning
If you want your system to remain safe, before opening any attachment in an email it is good that you analyze it through a free or paid platform. Some tools for analysis of malware in suspicious files are:
VirusTotal.Notmining.PassiveTotal.Apility.Apivoid.Polyswarm.Hybrid Analysis.
How to learn more?
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