Almost a quarter of HTML email attachments are malicious
When used legitimately, HTML attachments in emails enable organizations to share content, such as newsletters or invitations, that display properly when opened in an email client or web browser.
But a new report from Barracuda reveals that 23 percent of HTML attachments are malicious, making them the most weaponized text file type. Overall more than three-quarters of the malicious files detected overall were HTML, and 24 percent of email messages overall are now unwanted or malicious spam.
Malicious HTML attachments double in the last year
Last May, 21 percent of all HTML attachments scanned were malicious. Ten months on, that figure has more than doubled with 45.7 percent of scanned HTML files found to be malicious in March 2023.
This finding comes from the latest Threat Spotlight report from Barracuda Networks, which shows that not only is the overall volume of malicious HTML attachments increasing, they remain the file type most likely to be used for malicious purposes.