Russian activists Georgy Alburov (member of Anti-corruption Foundation) and Oleg Kozlovsky (member of Solidarnost movement) found their Telegram accounts accessed from same NY IP address 162.247.72.27 (which is Tor exit relay running by The Calyx Institute https://globe.torproject.org/#/relay/6C143720FFF8469EF6A5C5B4066366340CF6C0D... ) using telegram-cli. They did not have two-factor authentication enabled (Telegram by default uses one-time passwords received by SMS, but you can also enable "two-factor authentication" which is asking a password when you try to login with new device) and they didn't received the SMS message, so it's looks like SS7 attack. Russian government known for it's exploiting SS7 vulnerabilities (and those are not really vulnerabilities which can be easily fixed, those vuls exists because SS7 was designed that way). MTS, telecom provider used by Alburov and Kozlovsky, commented that SMS receiving was disabled on their accounts for some time. I also have some evidence that Russian authorities uses same method for logging into Facebook accounts (Facebook also have a feature called "one-time password" https://www.facebook.com/help/447046021986895 which allows to send SMS with text "otp" to Facebook number and receive a code which is enough to login into Facebook). SS7 designed such way so this is not required for attacked to be in same country as you. It's not required for your telecom provider to cooperate. All you need is an access to SS7. Security services have it, private spies have it, and you can have it: there is plenty of companies selling SS7 access. So if you use Telegram, enable two-factor authentification. If you use Facebook, turn on login approvals https://www.facebook.com/help/148233965247823 If you using any service which allows you to login just with code received by SMS, find out a way to turn off this or stop using this service. If you thinking about such feature in your service, please don't do so. See also: News report https://meduza.io/news/2016/04/29/aktivisty-oppozitsii-pozhalovalis-na-vzlom... (in Russian) Kozlovsky's post with details received from MTS https://www.facebook.com/kozlovsky/posts/10208948934790884 (in Russian) The Critical Hole at the Heart of Our Cell Phone Networks https://www.wired.com/2016/04/the-critical-hole-at-the-heart-of-cell-phone-i... which covers some previous SS7 attacks by Russian govt and SS7 design SS7: Locate. Track. Manipulate https://www.youtube.com/watch?v=lQ0I5tl0YLY great talk by Tobias Engel on 31c3 about SS7 SS7map https://ss7map.p1sec.com map covering SS7 issues -- https://nesterov.pw GPG key: 0CE8 65F1 9043 2B11 25A5 74A7 1187 6869 67AA 56E4 https://keybase.io/komachi/key.asc