Cybercriminals are increasingly using malicious HTML files to attack computers, according to a recent study conducted by security researchers. In addition to this, Barracuda Networks' study also revealed that malicious files now account for over half of all HTML attachments sent via email. There has been a significant increase in applications compared to last year.
Is there a phishing scam using HTML attachments you know of? To prevent cybercriminals from contacting C7C servers to download crypto-malware, Trojan horses, or other nasty nasties through email, HTML attachments are sent instead of email.
Phishing scams based on HTML emails have been around for a long time, but people aren't aware of them, and they are increasingly falling for the same.
There is a high chance that you checked your email more than once this past weekend. This is despite it being a holiday weekend for many people.
Even though HTML files continue to be one of the most common attachments used in phishing scams in 2022, it shows that the method is still one of the most effective methods of getting past spam detection software and delivering spam to targets who are looking for it.
HTML (HyperText Markup Language) is a markup language developed to display documents created for display in a web browser, according to Wikibooks. The capabilities of technologies such as Cascading Style Sheets (CSS) and programming languages such as JavaScript can make it easier to do this.
It is possible to render HTML documents as multimedia web pages using a web server or a local storage device that receives HTML documents from a web server. An HTML document describes the semantics of a web page and includes clues that indicate how it should appear to the end user. HTML can also describe the content of a web page.
When victims are sent phishing emails using HTML files, they are frequently directed to malicious websites, downloaded files, or phishing forms that can be displayed locally within their browsers on their computers.
It is common for email security software to overlook attachments when delivering messages to targets since HTML does not pose a threat to the recipients; as a result, messages are delivered successfully to their inboxes.
Something is interesting about this recent increase in malicious HTML files. This does not seem to be the result of mass attack campaigns in which hackers send the same attachments to many victims.
To protect against cyberattacks, it is now more imperative than ever to implement appropriate cybersecurity measures. The key to preventing such attacks is what the report uses as an example of how to prevent them.
It has been reported that the cybercriminal groups DEV-0238 and DEV-0253 have also been using HTML smuggling to deliver keyloggers through HTML attachments they have sent using HTML smuggling. HTML smuggling has also been associated with the cybercriminal group DEV-0193 delivering Trickbot malware through HTML smuggling.
HTML attachments are used in phishing attacks
HTML attachments spammed by phishing sites are the most common type of HTML attachment. There is generally no malicious code within the HTML file itself. This means it does not have any malicious code that launches arbitrary code into the system even though it looks benign. Despite this, it is recommended to treat this attachment with caution. By mimicking the look of a sign-in page for a service such as Microsoft, Google, or a major online bank, the scam could lead to the user entering their credentials into the form and submitting it, resulting in a malicious website that takes over their account.
When it comes to spam forms and redirection strategies in HTML attachments, hackers usually use several tactics for implementation. These tactics range from simple redirections to obfuscating JavaScript to disguise phishing forms to steal personal information.
A secure email gateway and antivirus solution can check email messages for attachments to see if they contain malicious URLs, scripts, or other threats. This could threaten users' security.
The majority of cybercrime attacks are composed of malicious phishing forms or redirects created using JavaScript in HTML attachments. This is done to avoid detection.
Considering that malicious files can damage your device and your organization, it has become increasingly important to ensure you take the necessary precautions to keep yourself safe from them. It is imperative to know how to prevent such attempts by taking the following precautions:
The infrastructure of your email system will be crucial in this case. Antivirus software and firewalls should be updated regularly to function properly. Furthermore, a solid plan of action must be implemented for data loss prevention. DMARC protocols should be defined for your domain as the most effective way to ensure communications security.
Authenticating with two-factor authentication is necessary, followed by zero-trust access based on multi-factor authentication. You can be sure that your employees will be protected even if they fall victim to hacker attacks, credential theft, and phishing. This is because they will evaluate their credentials, device, location, time zone, and history of access and limit breaches.
The importance of employee training on recognizing and reporting malicious HTML attachments shall be recognised. Employees must be trained on how to recognize and report attachments from unknown sources, especially those containing malware. Cybersecurity threats can have serious consequences for a business organization if it is not prevented.
Certainly, obfuscation is one of the common denominators among all the spammed HTML attachments in this case. Having to deal with a threat like this at the email gateway layer demonstrates just how difficult it is to detect.
