IMSI catchers are used by law enforcement, but some companies appear willing to sell to private individuals too.
Across a tinny Skype connection, a Hong Kong tech company is trying to sell us state surveillance equipment.
"I switched it on already," says Edward Tian, holding up a backpack containing a box and wires. "This is the antenna. This is the battery […] Everything is this simple."
It's a $15,000 IMSI catcher operated via an Android app. Tian shows us the user interface in a grainy video. He hits a button on the app and information on a bunch of cellphones in the area trickles down the screen. He has their IMSI (International Mobile Subscriber Identity, a unique identifier for their SIM card), IMEI (International Mobile Equipment Identity—the same for their device), and even full phone numbers.
IMSI catchers are pretty well established pieces of surveillance tech used by law enforcement all over the world. The portable device essentially acts like a fake mobile phone mast: When it's switched on, it captures the IMSI of every phone in the area. From there, it can intercept messages, calls and data, and block phones from operating, among other functions.
IMSI catchers are illegal to operate (unless you're law enforcement), although plenty of hackers claim to have made them. But we were posing as businessmen as part of our investigation for a Vice News documentary to see whether Tian's company, HK Medsourcing was willing to sell them to private companies.
"Sure," he replied. "Yeah. Some private companies."
"A trade company or an investigation company, any company like this," he added.
Stressing that we weren't from the state, we asked him if he could make arrangements for us too.
"We are not very clear about the local law, about the recommendations," he said. "So you need to assure us that you are using it legally. And we make arrangements according to your requirements. That's not a problem."
Tian's company, HK Medsourcing, is one of a number that are filling a gap in the tactical surveillance market.
Western companies that sell surveillance tech have to obtain export licenses that effectively restrict the sale of equipment to repressive regimes and private individuals, following a 41-state pact called the Wassenaar Arrangement.
This is not always straightforward. Export controls data show that the UK granted licences for £5.2m ($7.5m) worth of "telecommunications interception equipment" over a 5-month period last year, to countries including Qatar, Indonesia, UAE—hardly places with creditable human rights records.
Government contracts from repressive regimes are lucrative, however, and it seems inevitable that if Western companies face criminal charges for exporting surveillance tech to places like Syria, unregulated companies will fill the gap.
HK Medsourcing, for instance, claimed to have attended a tender for the Bangladeshi police the week prior to our call—an outfit that had previously failed to obtain an IMSI Catcher from a Swiss company after it was blocked by the government.
The company also claimed to have done business with Russia, African countries, South American countries, and numerous private companies and dealers—the implication was that beyond sales to state law enforcement and intelligence, there is a market for user-friendly tactical surveillance technology: things like IMSI Catchers, geolocation tools, malware and spyware.
"There's a whole range of groups that would be interested in these kinds of tools," said Edin Omanovic, surveillance tech exports officer for Privacy International. "Not just individuals, but private military companies and private security agencies. For example, a private security agency that's running a prison, or a personal security agency for a political leader, may well find uses for tactical surveillance equipment."
The lawful interception industry is expected to reach $1.3 billion by 2019, according to Markets and Markets research firm, up from $251m in 2014. But the emergence of a black market raises the question of who else will benefit from the technology—and who will take the profits.
"It's a very big problem," said Frederick Tonelli from Spectradome, which sells a range of tech including devices for tactical surveillance. When we met him at 2015's Milipol, a global exhibition of state security, he also noted the phenomenon of companies from China selling to members of the public on the black market. His company only sells to legitimate state buyers.
"We continuously research and develop new systems and we try not to disclose too much information because that kind of information could be used not only to reverse engineer our systems but also to find a way to fight against them," he said. "And we're providing the good guys with tactical advantage."