Out-of-the-blue empty emails bring redirecting malware danger

Have you received an email out of the blue with no message body, but with a file called

<random number>_inv.html

attached?

Well, be on your guard – as you could be in the firing line for a new malware attack that has been widely spammed out around the world.

Here is just a small snapshot of the different subject lines we’ve intercepted at our global network of spam traps:

If you make the mistake of opening the attached HTML file your computer will be redirected to a fake anti-virus attack on a third party site. That means that you will begin to see bogus security warnings trying to trick you into handing over your credit card details, or to download further dangerous software to your computer.

Sophos’s products don’t have any problem intercepting the messages above as spam (and we’ll be detecting the attachment as Troj/JSRedir-CO shortly), as well as intercepting the webpage that the attack attempts to connect with and blocking the fake…

Read more in my article on the Naked Security website.

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Graham Cluley •   @gcluley

Graham Cluley is a veteran of the cybersecurity industry, having worked for a number of security companies since the early 1990s when he wrote the first ever version of Dr Solomon's Anti-Virus Toolkit for Windows. Now an independent analyst, he regularly makes media appearances and is an international public speaker on the topic of cybersecurity, hackers, and online privacy. Follow him on Twitter, Mastodon, Bluesky, or drop him an email.