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Hacking into Whatsapp | What is SS7 Flaw ? | Explained

Hackers have again demonstrated that no matter how many security precautions someone takes, all a hacker needs to track their location and snoop on their phone calls and texts are their phone number. The exploit centers on a global system that connects mobile phone networks and can give hackers, governments or anyone else with access to it remote surveillance powers that the user cannot do anything about.


But how can this happen, is it currently being used and what can you do about it? Signalling System No 7 (SS7), which is called Common Channel Signalling System 7 (CCSS7) in the US or Common Channel Interoffice Signaling 7 (CCIS7) in the UK, is a system that connects one mobile phone network to another.


Mobile phone networks have also employed security contractors, including the German security researcher, Karsten Nohl, who uncovered the flaw in 2014 and demonstrated it for 60 Minutes, to perform analysis of the SS7 systems in use to try and prevent unauthorized access.



Nohl said: “The mobile network is independent of the little GPS chip in your phone, it knows where you are. So any choices that a congressman could’ve made, choosing a phone, choosing a pin number, installing or not installing certain apps, have no influence over what we are showing because this is targeting the mobile network. That, of course, is not controlled by any one customer.”


SS7 is a set of protocols allowing phone networks to exchange the information needed for passing calls and text messages between each other and to ensure correct billing. It also allows users on one network to roam on another, such as when traveling in a foreign country.

How SS7 enable hackers to do Hacking into Whatsapp?

Critical SS7 Cellular Network | Hacker Nucleus
Critical SS7 Cellular Network | Hacker Nucleus

Once they have access to the SS7 system, a hacker can essentially have access to the same amount of information and snooping capabilities as security services.


They can transparently forward calls, giving them the ability to record or listen in to them. They can also read SMS messages sent between phones, and track the location of a phone using the same system that the phone networks use to help keep a constant service available and deliver phone calls, texts, and data.

Who is affected by the vulnerability?

Should a hacker gain entry to the SS7 system on any number of networks, or if they are used by a law enforcement agency as part of its surveillance, anyone with a mobile phone could be vulnerable.

What’s being done about it?

Since the exposure of security holes within the SS7 system, certain bodies, including the mobile phone operators’ trade association, the GSMA, have set up a series of services that monitor the networks, looking for intrusions or abuse of the signaling system.

Nothing is hack-proof, however, and their success will likely be on a network-by-network basis. Reportedly, recent security testing of SS7 by an operator in Luxembourg took Norway’s largest network operator offline for over three hours due to an “unexpected external SS7 event”.

The risk of surveillance of your average user, given the billions of mobile phone users across the globe, is small. Those in a place of power, within organizations or government, could be at risk of targeting, as all that’s required to perform the surveillance is access to the SS7 system and a phone number.

One of the biggest dangers, beyond someone listening to calls and reading text messages, is the interception of two-step verification codes that are often used as a security measure when logging into email accounts or other services sent via text message. Banks and other secure institutions also use phone calls or text messages to verify a user’s identity, which could be intercepted and therefore led to fraud or malicious attacks.




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