Earlier today, the New York Times issued a warning over Twitter and also on the front page of the web site. The newspaper advised visitors that they had had reports from “some NYTimes.com readers” relating to a malicious pop-up window while browsing the site.

In the warning, the influential newspaper stated their belief that the pop-ups were the result of an “unauthorised advertisement”. From some online discussion it looks as though the problem may have been ongoing for upwards of 24 hours.

The pop-up window itself, (screen shot captured by quick-witted reader of All Things Digital) was the all-too-familiar sight of rogue antivirus software informing the NYTimes reader that their computer is infected with random, spurious, non-existent malware and promising “Full System Cleanup” for a fee of course.

Image courtesy of All Things Digital

The malicious software being punted in this case, is similar to what we were seeing in much of the black-hat SEO around the 9/11 attacks, as reported previously on the TrendLabs malware blog.

In this particular example, the malicious site and sofware is being hosted by a German provider, Hetzner AG, which has a colourful track record when it comes to spewing dodgy content, having hosted literally hundreds of malicious URLS.

Here’s a really simple tip to remember. If you *ever* see a browser pop-up window that arrives uninvited, telling you your PC is infected, ignore it, it is a scam. Close the window, empty your browser cache and to be on the safe side, run a real scanner like HouseCall. To be more fully protected in future, make sure you install an antimalware program that will also block malicious URLs, rather than simply looking for malicious files.

UPDATE: Troy Davis was fortunate enough to be able to examine the attack in real-time and provides an excellent code level analysis here.

UPDATE: The fake AV program being pushed in this attack was called Personal Antivirus and is very much a classic piece of scareware.

On install the application will start “scanning” your machine for problems. On a completely fresh installation of Windows Vista, it supposedly detected 38 threats.

Of course none of these imaginary threats can be removed until you pay to activate you copy of this useless software, not only giving away your cash but also of course all your credit card and personal details at the same time, double-whammy for the cybercrooks.

If you choose not to activate the software immediately you will then be served at random intervals with fake messages informing you of yet more detected problems, when you hit the “Block” button, you are again prompted to pay for the software, and so it continues…

For cleanup, use HouseCall or any other reputable security software, a helpful list of what is real (as opposed to FakeAV) can be found here.