When Drones Attack: The Threat Remains Limited

A series of recent events has me again thinking about the security threats posed by unmanned aerial vehicles — commonly referred to as drones.

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On July 10, a drone bearing two hand grenades crashed outside the home of Gerardo Manuel Sosa Olachea, the secretary of public security of Baja California state. This incident also involved a second drone, but it was unknown whether that one was also armed or if it was just being used to observe the attack. An analysis of photos of the crashed drone shows it was carrying South Korean fragmentation grenades, a popular weapon among Mexican cartel gunmen, but did not reveal the intended triggering mechanism for the grenades. The drone involved in this incident was a larger, six-rotor model of a type that previously has been used to smuggle small bundles of narcotics across the U.S. border from Mexico.

That same day, Italian authorities announced that carabinieri in the southern province of Potenza had arrested a Macedonian grassroots jihadist who they believe was preparing to conduct an attack using a drone. During a search of the man's apartment, police reportedly discovered that he'd downloaded jihadist videos that covered a number of topics, including how to arm commercial drones. They also seized an unspecified number and type of commercial drones, along with military clothing, but they did not find any explosives. Either he had cached them elsewhere or, more likely, he was still very early in the attack cycle and had not yet acquired weapons for his drones. 

Attacks involving drones likely will only become more common and will eventually pose a global concern. On July 11, the Combating Terrorism Center at West Point published a study of the Islamic State's drone program by Don Rassler that detailed how the group was able to obtain commercial drones and components that it used to conduct both surveillance and attacks. Rassler's study traced how an array of companies owned by a pair of Bangladeshi brothers in the United Kingdom, Bangladesh and Spain bought drones and parts and shipped them to Turkey to be smuggled into Islamic State territory. The complex, transnational supply chain that enabled the jihadist group's robust drone program could be replicated elsewhere.

However, an individual or a small terrorist cell wishing to obtain a drone or two for an attack does not have to go to such lengths. Commercial drones are readily available around the globe. Most can carry relatively small payloads — the popular DJI Phantom 4, for example, can bear just over a pound. Heavy-lift drones available for commercial sale that can carry over 20 pounds are far more expensive, and their purchasers will face more scrutiny. However, as the technology matures, and drones become more common, it's likely that payloads will increase while prices decrease.

Obviously, non-state groups armed with military-grade drones provided by state sponsors — such as those supplied to Hezbollah and the Houthis in Yemen by Iran — pose a far greater threat. The recent cases in Mexico and Italy also highlight the limits of the threat posed by commercial drones, including the fact that obtaining one may be much easier than arming it with a functional weapon. In the case of the Islamic State, it had access to a wide variety of ordnance in Mosul that it could then use or modify for delivery by drone. It used manufactured military ordnance such as grenades, small mortars and bomblets salvaged from cluster munitions in the hundreds of drone attacks it conducted. The failed attack in Mexico, where cartels have ready access to military-grade weapons, followed this pattern. In other places where such ordnance is available, such as the Middle East, Africa, Southeast Asia, Latin America and even Sweden (where organized crime groups have conducted an alarming number of attacks involving grenades), drone attacks using military munitions are more likely.

But in many parts of the world where military weapons are less widely available, a would–be attacker would have to somehow acquire munitions. In recent years, there have been many cases in which grassroots jihadists reaching out for help in buying more powerful weapons have instead blundered into government sting operations. An attacker intent on delivering weapons with a drone could try to build some sort of improvised munition, which would also entail creating the explosive filler for it. However, that may be easier said than done. In several cases, grassroots jihadists have struggled to fabricate even simple explosive devices and viable homemade explosive mixtures, much less a drone-borne device capable of inflicting significant damage.

Obtaining bomb components, assembling them, testing them and then testing them with the drone all add complexity to the terrorist attack cycle, increasing the chances of the attacker being discovered in the preparation stages. But even if an attacker manages to conduct a direct attack using a drone, the physical damage that can be inflicted by home-brewed munitions, whether simple low-explosive pipe bombs or some sort of improvised fragmentation grenade using a more powerful explosive such as TATP, would simply not be as effective as a piece of purpose-built military ordnance.

Nevertheless, as demonstrated by the Islamic State's attacks in Iraq and Syria, the small pieces of military ordnance that drones are capable of delivering would inflict more psychological than physical damage. Indeed, even had Sosa Olachea been at home when the drone carrying grenades crashed outside his residence, and even had the grenades detonated as intended, the chances of his being wounded, much less killed, are small. Although it failed on an operational level, the attack still clearly sent a message.

In the event that an armed commercial drone were used to attack a large crowd, the psychological effects would likely cause more harm than the device it delivers. A stampede of panicked people, for instance, could inflict more injuries than an explosion. Thus, it is important that people realize the limits of the drone threat so as not to overreact and multiply the impact of an attack with trampling damage. Because drones at this point are likely to be more successful in instilling fear than causing actual physical damage, they could be categorized as a true terrorist weapon.

It is also important to keep in mind that the misuse of drones is not confined to direct attacks. The devices, which are quite effective surveillance platforms, can be used to gather intelligence on facilities, residences or the comings and goings of potential human targets, facilitating the planning of attacks by other means. The effectiveness of drones as surveillance tools should be a particular concern for corporate security and executive protection teams, which should take steps to look for them in addition to watching for traditional surveillance conducted by human operatives or static cameras on the ground. From a target's viewpoint, the use of drones for surveillance can alter the appearance of the attack cycle. But since attackers still must follow the cycle, the points of vulnerability that it exposes them to remain the same.

Scott Stewart supervises Stratfor's analysis of terrorism and security issues. Before joining Stratfor, he was a special agent with the U.S. State Department for 10 years and was involved in hundreds of terrorism investigations.