Malware attacks disguised as legitimate security applications or patch/vulnerability advisories continue to proliferate rapidly, further establishing the mainstream's heightened sensitivity to online threats as a seemingly viable threat model.

The fake anti-virus angle first appeared several years ago, but according to recent reports, anti-malware vendors are seeing security-themed threats take over an increasingly large piece of the pie, in terms of the most widely used attack tactics.

Taking a look at Sunbelt Software's top 10 most prevalent spyware threats for the month of September, published yesterday, four of the listed attacks clearly have been crafted to play on end users' desire to keep their devices more secure.

Typically the programs advertise themselves as having the ability to scour endpoints for infections, only to infect the devices themselves, and then demand users to pay for additional programs that can clean up the viruses that they claim to find.

Whereas only several years ago people were being told to look out for files that fairly well advertised themselves as attacks, or in the least used very noticeable gibberish or silly file names, now we're asking folks to differentiate between the good stuff they need to protect themselves and badware dubbed "Ultimate SecuritySuite" or "Antivirus XP 2008."

That's pretty scary when you consider that many end users are only just now figuring out just why they need AV, or how it works, in the first place. On top of that, you have the mainstream media furthering the spread of FUD on a near nightly basis, not that it's a bad thing, really, but it most likely leads some people to swallow just this sort of bait we're talking about.

On top of the fake AV model's expansion, we're also seeing timely attacks related to issues of security, such as last week's pre-Patch Tuesday threat that was advertised as a "Security Update for OS Microsoft Windows" and sent from the "Microsoft Official Update Center."

Of course, with everyone preparing for Oct. 14's batch of Patch Tuesday bulletins, and the Microsoft attack being crafted to appear almost exactly as a legitimate missive from the software maker would look, even including the signature of Steve Lipner, director of security assurance at Microsoft, one has to think that more than one end user might have taken the bait lying therein.

I mean, who can you trust?

The answer is no one. Not even messages that appear completely innocuous or just like the overnight receipts, e-ticket verifications, or, yes, even the security software updates that we're used to receiving in our in-boxes every day.

Caveat emptor was created by the Romans in a time when people were probably most concerned with buying donkey meat at the local market when they thought they were purchasing goat meat.

And while we're not necessarily buying everything that finds its way onto our computer screens, people simply just need to become even more wary that every form of electronic communication that they receive might be some sort of attack, no matter what it looks or promises to be.

So don't let security insecurity leave you insecure. Just buy your AV from a trusted source and check vendor sites for security updates before you go clicking those attachment or links. It's worth the effort.

Matt Hines has been following the IT industry for over a decade as a reporter and blogger, and has been specifically focused on the security space since 2003, including a previous stint writing for eWEEK and contributing to the Security Watch blog. Hines is currently employed as marketing communications manager at Core Security Technologies, a Boston-based maker of security testing software. The views expressed herein do not necessarily represent the views of Core Security, and neither the company nor its products and services will be actively discussed in the blog. Please send news, research or tips to SecurityWatchBlog@gmail.com.