Islamic State has incited its followers to pose as fake sellers on popular buy-and-sell websites such as eBay and Gumtree to lure unsuspecting site users to their deaths.

The extremist group issued the instruction in its English-language propaganda magazine Rumiyah, titled “Just terror tactics”.

“The viewing and collecting of the item should be arranged to be at the location where one seeks to carry out his operation,” the article read.

“Upon the target’s arrival, one can then proceed to initiate his attack.”

University of New South Wales Canberra cyber security professor Greg Austin, who has worked in counter terrorism roles, told The New Daily the naming of specific websites was “definitely alarming”.

He said it was likely these threats could extend to dating apps and other sites such as Airbnb.

“In the same way we see copycat crime, we will almost certainly see a victim of a terror attack based on some form of online advertisement. Or, perhaps more likely, a dating app.

“But it’s important to remember that incidents of terror attacks are relatively small in Australia. You’re much more likely to be mugged or raped, than killed by a terrorist.”

The federal government’s national security website states that the terrorist threat level in Australia has been elevated since September 2014. Since then, there have been four terrorist attacks and 12 disrupted terrorist plots.

A hostage runs to safety during the Sydney Lindt Cafe siege. Photo: AAP

“I don’t think the changing technology will make it worse but the easing familiarity that technology breeds means we’ve lost our sense of ‘stranger danger’,” Professor Austin said.

“From a psychological point of view, IS want to instil fear. Terrorists have all sorts of opportunities without needing to lure people. This instruction is really about creating fear.”

Deakin University professor Matthew Warren, deputy director of the Cyber Security Research Centre, told The New Daily that in targeting such websites, IS had revealed a “weakness”.

Professor Warren said that in recent times, social media platforms such as Facebook and Twitter, which IS traditionally used for recruiting purposes, have become better at managing and removing pro-IS content.

IS’s apparent new focus on buy-and-sell sites was therefore telling of its growing frustration with online monitoring systems and may be a sign of “desperation”, he said.

“IS is having many global setbacks and, to bypass this, it would seem they’re looking to use alternative approaches,” Professor Warren said.

“This concept is primarily aimed at creating a sense of fear for sites we know and trust.”

Professor Warren likened this method to that used by other terrorist groups, such as the Irish Republican Army using pretty girls to lure oblivious soldiers to their deaths during the 1970s and ’80s.

“It puts these companies like Gumtree in an awkward situation because it’s difficult to monitor, and users may not necessarily communicate through the site itself. For example, they might exchange phone number,” he said.

“IS is trying to manipulate people’s perceptions of technology because people trust technology; they trust sites like eBay and Gumtree.”

How to keep safe

Professor Austin recommended conducting research before committing to a purchase from a stranger on such a website.

“Something that I do myself is to make sure that the person you’re dealing with is well recommended by at least 20 or 30 odd other users,” he said.

“Another good technique is to call the person directly to ascertain more detail.”

Gumtree has urged users of its online classifieds to report anything suspicious.

“The safety of our community is our main priority and we urge anyone who thinks they’ve come across anything suspicious or concerning to report it to us,” a spokesman said.

“We encourage all users to visit our ‘help’ section for tips on how to have a safe and successful experience and to be vigilant when using any online marketplace.”

– with AAP