By Chris Stephens, Head of Banking Solutions at Callsign
In our day-to-day lives, SMS one-time passwords, also known as OTPs, have unintentionally become the default authentication factor when carrying out high risk and confidential transactions online. Banks, telcos, and businesses are opting for this method as SMS OTPs are relatively quick and simple to put in place. In our digital age, this solution works for the majority of users, who more often than not possess a mobile phone and are familiar with the user experience. As a result, companies are using them to securely authenticate both their customers and employees.
When looking into SMS OTPs, businesses should consider the bigger picture and how time- and cost-efficient solutions are as a whole by taking into account other key elements that might have been neglected in the past, such as hidden fees and security vulnerabilities. Apart from this approach, there are also other options better suited to different business needs – the European Authority (EBA) has already recognised other forms, such as employing the secure binding of a device to achieve possession and the use of behavioural biometrics as an inherence factor. For example, earlier this year Google officially began moving away from SMS OTP-based authentication. Whilst in the UK both the Financial Conduct Authority (FCA) and UK Finance have recommended banks ought to reduce their dependence on its use in the longer-term. Whereas, in the past, financial institutions were choosing to use this solution because it enabled them to save time on becoming compliant with the PSD2 Strong Customer Authentication (SCA) regulation.
It is common knowledge that SMS OTPs are not without their flaws, and with the extended deadline for SCA for e-commerce less than a year away (September 2021) – is now the best time for the industry to look elsewhere for more intelligent approaches to authentication?
SMS as the go-to solution
Fraudsters are sophisticated criminals, who attack the weakest points in the system – they have observed that banks and businesses heavily rely on SMS OTPs for 2FA (two-factor authentication) transactions, which is why they continue to abuse and weaken existing systems and exploit these solutions for their own benefit. Fraudsters commonly practise SIM-swap – where they steal personal information about the victim and then contact the target’s mobile operator pretending that their phone has been lost or stolen. With lockdown rules constantly changing, not all customers are able to easily visit stores right now, therefore operators are dependent on mobile-authentication channels that are more susceptible to this type of manipulation to service their customers.
SIM-swap fraud can easily be done. As soon as the fraudster has duped the mobile operator, a number transfer is authorised and then activated on a new SIM card – it works by granting cybercriminals access to the victim’s number and consequently all one-time passwords and authentication codes that are sent to that number. In March 2020, Europol warned that SIM-swap scams are a growing problem across Europe, following an investigation that resulted in the arrest of 12 suspects associated with the theft of more than €3 million ($3.3 million).
However, consumers and businesses need to be aware that SIM-swap fraud is not the only method cybercriminals are deploying to intercept OTPs from their victims during the pandemic and beyond.
Spotting a scam
SIM-swap attacks are not the only method scammers are using, there is also a growing number of cases that take advantage of malware and remote access applications to steal SMS OTPs. They do this by socially engineering individuals to download remote access apps or hidden surveillance apps to grant access to the victim’s device, without coming into contact with it. The cybercriminals can, therefore, directly read their messages or secretly record all their texts and phone calls to another device. The unknowing victim’s personal messages, including OTPs, are tapped into by the fraudster using the same approach as SIM-swap attacks. However, this time they also have direct access to the target’s device.
Several different parties are involved in the delivery of OTPs and at each stage of the process there is an opportunity for fraudsters to capture messages. There is also the potential mass compromise as a result of hidden vulnerabilities in the SS7 network and the attack surface to consider. With all these in mind, banks need to have a good overview of all data sub-processors to allow them to adopt the most suitable security controls, such as multi-factor authentication (MFA), audit logs, and dashboards.
Watch out for hidden costs
It comes as no surprise that intercepted OTPs result in fraud losses, which quickly increase as hidden fees go unnoticed over time. Beyond the upfront costs of SMS OTPs, such as cost per text, there are also several hidden costs that are difficult to budget for and avoid. They are typically the result of the domino effect of the aforementioned issues – forcing businesses into a reactive mode that is tricky to handle.
As an example, where drop-offs take place in an authentication journey, including when SMS texts are not received, financial institutions need to be ready to manage an influx in calls to their customer service helplines and the associated fees. Or else the customer may decide to use another card to make the payment, which is worse for the bank. This is due to the fact that customers are likely to abandon the use of a card when they are fed up with a customer journey that involves too much unnecessary friction. These abandonments lead to a decrease in interchange fees for banks and could even potentially reduce the customer base for merchants.
Evaluating the user experience
Whilst most consumers possess a mobile phone, SMS is not a reliable solution for everybody. For instance, SMS OTPs are not accessible to those living in remote or low-service locations, who may struggle to receive SMS alerts. This overall experience is also cumbersome as it takes roughly 30 seconds of transaction time for the text to be delivered, compared with the almost instantaneous transactions experienced by alternative authentication approaches, such as biometrics.
In this digital age, businesses are constantly adapting to accommodate different generations including Gen Z who are digital natives – so mobile use is only going to increase and, along with it, the volume of transactions taking place on these devices will also grow. This goes hand in hand with the ever-changing needs and expectations of customers as they look for hyper-personalised online experiences as the new norm. Yes, SMS OTPs are mobile-first, but they do still require the user to switch to another app to view the SMS so they can complete the transaction, which can be annoying for the customer as it interrupts the e-commerce user journey. After a friction-filled experience, it would be unsurprising if the user then decides to abandon the transaction. With this and other existing security implications in mind, the EBA recommends banks adopt other options.
Benefits of behavioural biometrics
Every person has their own unique behaviour and habits when swiping across the screen, which can be tracked through the analysis of the data signals captured from hardware sensors when the user engages with their device. These signals are crucial to designing user features such as finger movement, hand orientation, and wrist strength. Together, artificial intelligence and machine learning provide us with the capability to analyse this information to develop a personalised prototype of that user’s swipe behaviour, which only takes milliseconds to confirm whether the customer is who they say they are. This immediately allows the bank to seamlessly carry out appropriate security actions and stop fraudsters in their path before they can even begin using a target’s device.
Behavioural biometrics is ideal for positively identifying an individual and also effectively identifies bad actors. Including when cybercriminals use technologies, such as bots or remote access Trojan (RAT) software, to control transactional flows without the user being aware. This approach to biometrics works on both high- and low-end devices and helps to protect potential victims against both blind (where the fraudster has never observed how the user swipes their phone) and over-the-shoulder attacks (where the fraudster has been able to observe the victim’s swipe movements). Both forms of attack can be detected unique algorithms, with an accuracy rate of 98%; by layering in device intelligence and locational habits it is the most accurate and robust identification method currently available on the market. By preventing criminal access, even when the attacker has observed the user’s behaviour, it offers an added level of security to businesses and banks that other traditional methods, such as a PIN or password, cannot.
In order for organisations to maintain a competitive edge and successfully navigate through the pandemic, they will need to deliver hyper-personalised journeys to meet consumers’ expectations. They are increasingly looking to bank with or sign-up to services that offer a secure and bespoke service that meets their daily needs during and beyond the pandemic.
Therefore, a holistic approach to security empowers businesses to take back control of their fraud and authentication management. Unfortunately, single point solutions, like SMS OTPs, do not allow businesses to scale or provide enough flexibility to meet these requirements. By adopting a strategic, and intelligence-based, approach financial institutions and organisations will be able to upgrade security measures and enhance the user experience – whilst keeping IT spend low.