When we think of the weapons that the terrorist group Islamic State (ISIS) uses, the first things that usually come to mind are guns and bombs.

The hacking collective known as the Ghost Security Group, however, discovered this month that the jihadist organisation is using another kind of weapon—one that seems so harmless that common people will not think it would be used by the terrorist group: a smartphone app.

Ghost Security Group is a hacking collective much like Anonymous, although it is more focused on counter-terrorism.

The ISIS smartphone app, available for Android devices, is similar to a news portal which distributes news items and videos. The only difference is that the ISIS smartphone app only promotes the group's propaganda.

This tech-based weapon for terrorist propaganda is ran by the Amaq News Agency, which is affiliated with the ISIS and was the first one to link the killings in San Bernardino to the jihadist group.

In a tweet earlier this week, the Kronos Advisory's Michael S. Smith revealed that the ISIS app even features news and videos showing atrocities committed by the terror group, such as executions and gunfights. Kronos Advisory is a defence contractor that works as an intermediary between Ghost Security Group and the U.S. government.

Smith was quoted by Time.com as saying that this app was developed by the jihadist organisation to "streamline access" to its "propaganda."

According to Ghost Security Group, the app cannot just be easily downloaded from usual marketplaces such as the Google Play Store.

For the app to be downloaded, a link is shared to Islamic State militants through Telegram or other secure, encrypted forms of communication. Only then can the user download and access the app using his or her Android device.

The hacking collective was not able to determine just how many people have so far downloaded this app. Nevertheless, this development highlights the alarming fact that the ISIS can use technology to promote its goals, without being detected by governments and private companies.