An enterprising group of criminals has been using a real-world scam in an effort to spread malware.

The attacks reportedly began with a series of phony parking tickets issued in Grand Rapids, North Dakota. Individuals had the tickets placed under their windshields along with instructions to visit a website.

Sans Institute security researcher Lenny Zeltser said that the website contained a number of photos of vehicles from Grand Rapids, and advertised a searchable archive of "bad parking".

The photos had been edited to remove licence plate information. Users visiting the site were instructed to download an executable 'toolbar' in order to search for their own cars.

The executable contains a Trojan application, however, which attempts to download a number of other malicious applications onto the victim's PC.

"Attackers continue to come up with creative ways of tricking potential victims into installing malicious software," said Zeltser.

"Merging physical and virtual worlds via objects that point to websites is one way to do this. I imagine we'll be seeing such approaches more often."

The method of attack impressed a number of other security researchers. Social engineering as a means of infection is not a new tactic for criminals, but using a real-world method such as a fake parking ticket is certainly new.

"This is a great example of real-world social engineering, placing fliers on cars informing you of a parking violation as a way to drive users to the web to download and install malware," said Dave Marcus, director of security research and communications at McAfee.