Understanding the Growing Threat of SIM Swapping Attacks

Have you heard of SIM swapping? Also known as a SIM hijack or SIM jack, it's a growing form of identity theft where criminals convince mobile carriers to port a target's phone number over to a SIM card under the attacker's control.

Once a SIM swap is successfully carried out, the attacker can intercept calls and texts intended for the victim, including SMS-based two-factor authentication codes. With control over the victim's phone number, cybercriminals can then access email, social media, banking and cryptocurrency accounts that rely on SMS as a second factor of authentication.

SIM swapping used to be a more focused attack that was typically directed at prominent people, such as influencers and celebrities. However, thieves trying to gain access to as many accounts as they can by using hacked phone numbers are using it more and more opportunistically. According to statistics, the number of SIM swapping incidents that are reported rises annually as more accounts link via SMS with mobile phone identities.

Even though SIM swapping is frequently accomplished through the social engineering of mobile telecom support teams, it shows how contemporary threats constantly adapt to get around established online security measures like text-based two-factor authentication. SMS is one of the most popular and straightforward types of 2FA, but it is also one of the weakest, which makes SIM takeovers a major avenue for phone hacking. This article will explain SIM swapping, why it is becoming more and more of an issue, and what you can do to guard against this new identity theft risk.

Why SIM Swapping is Effective for Criminals

Mobile verification is widely used: Cybercriminals find that SMS-based two-factor authentication is highly appealing, as evidenced by its widespread adoption on the internet. Attackers are aware that by getting hold of a target's phone number, they can access any accounts that have limited their second factor to phone-delivered one-time passcodes.

Financial accounts at risk: Banks, cryptocurrency companies, and payment platforms all frequently use phone-delivered OTPs. When a criminal uses SIM swapping to obtain someone's mobile number, they also gain access to that person's bank accounts.

Simple identity theft: A successful SIM swap can readily obtain targets' financial profiles in addition to personal information gleaned from email, social media, entertainment, and shopping accounts. Further downstream crimes such as tax fraud or applying for loans or credit cards in the victim's name are made possible by this identity harvesting. 

High reward, low effort: By using SIM swapping, criminals can compromise multiple online accounts associated with a phone number with minimal technical expertise, all thanks to the social engineering of mobile carrier employees. A SIM swap offers a comparatively high payoff for a small investment when compared to other hacking techniques.

How SIM Swapping Works

Attack vector for social engineering: The initial step typically entails calling the target customer's mobile carrier and pretending to be them. To persuade representatives that they are the actual account holders, attackers gather publicly accessible information about their target.

Phone number porting: After deceiving carrier employees, the thief will ask to have the target's phone number transferred to a new SIM card under their ownership. To do this, deactivate the original SIM card and use the number to activate the attacker's SIM card.

Bypassing 2FA: Carriers often do not require complex identity verification when porting numbers, allowing SIM swaps to be conducted without triggering account 2FA for the transfer. This leaves the process vulnerable to social engineering.

Intercepting SMS codes: With the number now connected to their SIM, the criminal can intercept any SMS-based 2FA codes the target would receive. They also prevent the true owner from receiving these time-sensitive codes.

Accessing accounts: Armed with stolen one-time passcodes, the attacker can then log in to any of the target's online profiles that solely rely on SMS as their second factor. Email, financial services, and other accounts are now compromised.

Covering tracks: Once in control of the phone number and accounts, some criminals will factory reset or discard the original SIM to cover their tracks and stall any efforts by the true owner to regain control.

Protecting Yourself from SIM Swapping

Use authentication apps: Instead of relying solely on SMS, enable mobile authenticator apps like Daito or Google Authenticator as a second factor for important accounts whenever possible. This is unaffected by switching SIM cards.

Enable login alerts: Set up email and SMS alerts from financial institutions and other sensitive sites so you are immediately notified of any access attempts.

Use a business phone number with Daito: Daito's business phone numbers are not attached to personal accounts, so thieves can't hijack the numbers through the traditional social engineering of carriers. SIM swapping methods don't apply to Daito numbers.

Freeze your SIM card: Contact your carrier to enable a PIN lock on your SIM card, making it useless if removed from your phone without the passcode.

Remain alert: Keep a close eye on all of your accounts to look for any unusual activity. After any trip, exercise extreme caution as location data obtained through social engineering could be used to target SIM swapping.

Report suspicious behaviour: As soon as you notice any unauthorised attempts to access or log into your account, notify your carrier. If you suspect that someone is hacking or SIM swapping, act fast to protect your identity.

Consider a SIM swap protection plan from your carrier. These days, some providers provide specialised monitoring services that can quickly return your number if it has been transferred.


Because SIM swapping can get around conventional SMS-based two-factor authentication, it presents a significant and underappreciated risk to account security. More robust secondary verification methods are needed to protect private financial data and online identities because social engineers can still exploit weak points in telecommunications authentication, like SIM transfers.

Businesses that handle customer or employee data run a significant risk because the security of an entire organisation could be jeopardised by a single SIM-switched employee. An alternative to SMS that is resistant to SIM hijacking, such as Daito's web-based one-time passwords, helps stop credential and account takeovers. Additionally, conventional phone porting techniques cannot be used to target Daito's phone numbers.

Daito enables security-conscious businesses to secure identities in a way that is resilient against even changing threats like SIM swapping by centralising multi-factor authentication management. Because of its emphasis on simplicity, authentication does not obstruct cooperation or productivity. Daito is the perfect answer for businesses looking for more security than SMS can provide against the growing threat of SIM swap identity theft.