I wrote an article before about ” What is GT (Global Title)? Why Do We Need It?”
What is Global Title Leasing?
GT leasing is the practice of a mobile operator entering into a commercial arrangement to allow another operator to use one or more of its GTS. Lessees obtain access to the global SS7 signalling network either via their lessor or a transit carrier and use their leased GTs as network addresses for their signalling node(s). A leased GT, therefore, enables the lessee to use the global SS7 signalling network to send signalling messages to mobile networks around the world.
Ofcom to stop criminals from intercepting calls and texts. The regulator has announced a ban on leasing special types of phone numbers, known as Global Titles, which mobile networks use to support services, ensuring that messages and calls reach their intended recipients. Mobile operators worldwide use Global Titles as a routing address for exchanging signalling messages, both within and between mobile networks, to support the provision of mobile services (e.g., for call routing and SMS delivery while roaming abroad).
Why!
An evil actor/attacker/hacker with such access may be able to use SS7 signalling to undertake a range of harmful activities, including:
• Illegal locating and tracking of end-users.
• Intercepting and diverting calls, messages and data.
• Accessing information held by mobile operators, contrary to privacy and data protection requirements.
• Disrupting the operation of networks.
When?
The ban on entering new Global Title leasing arrangements takes effect immediately. Ofcom also immediately banned the creation or use of GTS from sub-allocated numbers.