SIM Swapping Prevention

The LAPSUS$ cybercrime group which deleted 50TB of patient data from Brazil’s Ministry of Health have this week disclosed breaches on both Microsoft and Okta. LAPSUS$ are threatening to publish leaked data from Microsoft (source code) and Okta (clients) unless a ransom is paid. LAPSUS$ claim NVIDIA, Samsung, and Vodafone as targets that they have previously successfully breached.

LAPSUS$ use an identity spoofing approach involving SIM Swapping for gaining second factor control of a privileged account. This they achieve by recruiting internal employees at a telecom with the appropriate privileged access to commit a SIM swap. When they are ransoming for millions then $20k is a minimal overhead, but I would be extremely doubtful if they ever paid up!

LAPSUS$ hiring on Telegram

A SIM swap by itself will not lead to a breach as it requires the right individual target and potentially another authentication factor. Let’s therefore look at how SIM Swapping work and the steps necessary to make use of a such a privilege. We will also look at the steps the Chief Information Security Officer should put in place to protect against such low tech / high impact attacks.

What is SIM Swapping

SIM Swapping involves user impersonation to request a SIM change at the Mobile Network Operator but this is harder to do now so scammers are looking at getting the Carrier’s employees to commit a criminal act. Once the scammer has control of an employee then they can target the specific mobile numbers of target individuals for SIM swapping. They can then access the One Time Passcodes necessary to take ownership of a number of services that use SMS as a factor in authentication. It is the responsibility of the Mobile Carrier to prevent such malicious behaviour and should be endeavouring in auditing and social engineering protection for its staff.

Telecoms firms hire thousands of privileged users with administrative privileges in their call centres and central administration centres. A lot of these processes are often out-sourced at lowest possible cost to third parties. Furthermore it is not uncommon for out-sourced processes to be implemented in Robotic Process Automation tools with minimal code reviews potentially allowing corrupt users to leave undetectable backdoors open to key systems. Carriers must enforce good access control and access auditing on major processes that bear a risk for their customers. This means internal fraud prevention must be identifying points of weakness in advance and recognising inappropriate actions as quickly as possible and identifying end users.  The TM Forum’s Trust and Security Programme is a good start.

Protect Your System Administrators From Targeted Spear Phishing

As many as 1 in 100 System Administrators could be the victim of Targeted Spear Phishing attacks where they are blackmailed or connived into illegal behaviours. The UK National Crime Agency calculates the number of people in the UK with sexual interest in abusing children at 144,000 meaning that out of 26m adult males in the UK that 1 in 200 male sys admins can be blackmailed. Other threats such as a gambling problems, drug and alcohol dependence, other forms of blackmail cannot be ignored. For these reasons advanced vetting is recommended for all critical System Administrators with significant system access. Basic DBS checks should be the bare minimum. It is not possible to completely possible to remove all TSP attacks, therefore the security architecture must be appropriate and avoid using techniques which can be intercepted.

Switch Off SMS Based Authentication in Preference for Finger Print / Facial Recognition for All Employees

Okta and other Identity Management solutions allow the selection of which MFA credentials they will accept. There are risks with facial recognition and fingerprint spoofing, but these are much lower risks that interceptable SMS and One Time Passcode based MFAs. In the UK over 90% of mobile phone users are Smartphones and the penetration rate is above 100% amongst technologists. It therefore must be mandatory in any organisation that all System Administrators are using fingerprint or “Something You Are” biometric based MFA for privileged access. Remember though that regular password changes are increase the risk of breach as users move to easily rememberable passwords.

Conclusion: Always Have Backups Including Identity Management Platforms

With Dev/Ops and Infrastructure as Code it is possible to have backups to all systems that can be quickly redeployed. Have your architecture team review your systems estate for its complete recoverability so that you always have a fall back option. For transactional items keep a time series store of all transactions for recoverability. And every year run a full disaster recovery scenario planning practice day as a real event to understand as the CISO / CTO / CIO what are your risks.