Zello rose to fame in August 2017 when the 'walkie-talkie' app was used by relief effort volunteers and those stranded in the wake of Hurricane Harvey. The Russian government, however, wants to take the app down and this week it was revealed that the country's telecoms regulator told ISPs to prepare to block 15 million IP addresses, most belonging to Amazon, in order to do so.

Russia is developing a track record of being one of the most aggressive countries on the site-blocking front. Already many thousands of sites are rendered inaccessible to the general public but just how far will the government go to achieve its aims?

If reports coming out this week hold true, extremely far indeed.

The controversy centers around an app called Zello, which acts as a kind of ‘walkie-talkie’, assisting communication between close friends or in groups of up to a thousand people.

The app gained a lot of press in 2017 when it was revealed it was being used as an unofficial rescue co-ordination tool while Hurricane Harvey was battering the United States. It quickly shot to the top of the download charts after being downloaded a million times in a day.

But while the app clearly has some fantastic uses, Zello seems to represent a challenge to the authority of the Russian government.

Under the so-called ‘Yarovaya law‘, services like Zello, ISPs, and other telecoms companies, are required to register with Russian telecoms watchdog Rozcomnadzor. Amendments to come into force this year also require them to store the actual content of user communications for six months and metadata (such as who communicated with who, when, and for how long) for three years.

Encrypted services are also required to share keys which allow law enforcement bodies so that they can decrypt messages sent and received by users, something which has communications and VPN companies extremely concerned.

Until now, Zello has reportedly failed to register itself so as a result, the service has become a blocking target for Russian authorities. Zello uses Amazon Web Services (AWS) and last summer it was reported that dozens of Amazon’s IP addresses ended up on Russia’s official blacklist. This week, however, a much more worrying proposition raised its head.

Operators of at least four Internet service providers confirmed to Russia’s Vedomosti that Rozcomnadzor had issued recommendations that they block access to Zello. Copies of letters to the ISPs were published on Telegram and according to reports, most if not all of the country’s ISPs were targeted.

While blocking Zello would be bad enough, the suggestion of how that should take place is nothing short of astounding. The letter speaks of “an experiment” in which ISPs take action to block 36 Internet subnets – representing a staggering 15 million IP addresses – in order to take Zello down.

A total of 26 of those subnets have been identified as belonging to Amazon, accounting for 13.5 million IP addresses in total. Some are reportedly operated by Comcast, others by Softlayer, with the remainder connected to companies in China.

“The subnets selected by Roskomnadzor are not all Amazon’s IP addresses, but they account for a significant portion of the addresses from two large regions of the United States where the company’s data centers are located,” Vedomosti said, quoting a source familiar with Amazon’s infrastructure.

Zello founder and technical director Alexei Gavrilov said that he wasn’t surprised by the news and noted that he’d learned about the list of addresses from Telegram channels. However, it’s claimed that Zello doesn’t completely depend on the listed subnets, meaning that hundreds or thousands of other services unrelated to the app would end up as collateral damage, should they be blocked.

Neither Rozkomnadzor nor Amazon have commented publicly on the news and Russia’s Ministry of Communications has refused to comment. Fortunately, at the time of writing there have been no reports of ISPs mass-blocking IP addresses connected to Zello.

Whether Russia would really flex its muscles so broadly and aggressively just to prove a point is unknown but with the growing war on privacy the way it is, almost anything seems possible.