Access to the global network used to track phone calls and intercept messages, you can only for a few thousand dollars, found journalists Daily Beast as part of the investigation.

Having only one phone number available, an attacker with access to ACS-7 (Signaling System 7, SS7) can listen to conversations, send and intercept messages and perform other actions. Daily Beast journalists decided to find out how easy ordinary users can access this system. Journalists registered the domain smsrouter. co and under the guise of potential customers contacted the division of a major telecommunications service provider in Western Europe, positioning itself as a text message routing service.

After an exchange of e-mails within a week, the company offered journalists a connection to ACS-7 at a price of $ 2,650 with a 50% prepayment and a subsequent monthly fee of $ 6,600 for servicing the Global Title address used to determine the message delivery routes. The company also proposed to connect a fictitious company using the SIGTRAN protocol.

Then the TV company proposed to journalists to sign a non-disclosure agreement for further cooperation, but reporters decided to interrupt the experiment.

In general, access to the ACS-7 would cost journalists $ 9,250. This is a relatively small amount for most cybercriminals. The price indicated by The Daily Beast corresponds to figures from other sources. For example, in an email from the Italian company Hacking Team, published by WikiLeaks in 2015, CleverSig offered Hacking Team spyware on the basis of OCS-7. According to the letter, the monthly fee for this software was from $ 14 thousand. up to $ 16 thousand.

Access to ACS-7 can also be obtained on the black market. According to a source from the defense company OKS-7, there are several shadow players on the market offering access to SS-7 for a small fee. Most of these sellers are connected with East African telecommunications companies.

Recently there has been a rapid growth in the number of companies offering technologies for remote surveillance of mobile devices by exploiting vulnerabilities in the OCS-7.

OCS-7 (common signaling channel No. 7) is a set of signaling telephone protocols used to configure most telephone exchanges around the world on the basis of networks with time-division channeling.

The basis of ACS-7 is the use of analog or digital channels for data transmission and associated control information.

Global Title (GT) - the address used at the SCCP level of the SS7 model in alarm messages, for determining delivery routes in telecommunications networks.

SIGTRAN - the name of a group of telecommunications protocols created for the interaction of traditional telephony and VoIP. SIGTRAN protocols - expansion of the family of protocols OKS-7.