SIM Swapping Attacks: How They Work and How to Prevent Them

SIM Swapping Attacks

SIM swapping is a form of identity theft where an attacker convinces your mobile carrier to transfer your phone number to a SIM card they control. Once they have your number, they can intercept calls, texts, and two-factor authentication codes to access your accounts.

How SIM Swap Attacks Work

A typical SIM swap attack follows these steps:

• The attacker gathers personal information about you from data breaches, social media, or social engineering
• They contact your carrier pretending to be you, claiming a lost or damaged SIM
• Using your personal details to pass security questions, they request a SIM transfer
• The carrier deactivates your SIM and activates the attacker's SIM with your number
• The attacker now receives all your calls and texts, including 2FA codes
• They use these codes to access your email, bank accounts, cryptocurrency wallets, and social media

Real-World Impact

SIM swap attacks have caused devastating losses:

• Cryptocurrency investors have lost millions when attackers accessed exchange accounts
• Bank accounts drained through SMS-based two-factor bypass
• Social media accounts hijacked for fraud or extortion
• Email accounts compromised, leading to cascading account takeovers
• Business accounts breached through executive phone number hijacking

Prevention Strategies

• Stop using SMS for 2FA: Switch to authenticator apps (Authy, Google Authenticator) or hardware keys (YubiKey)
• Add carrier PIN: Set a PIN or password on your carrier account that must be provided for any changes
• Port freeze: Ask your carrier to add a port freeze or number lock to prevent transfers
• Minimize personal data: Reduce information available online that could be used to impersonate you
• Use eSIM: eSIM profiles cannot be physically transferred like physical SIMs can
• Monitor for signs: Sudden loss of cellular service is the primary indicator of a SIM swap

Why eSIM Is More Resistant to SIM Swaps

eSIM technology provides inherent protection against SIM swap attacks:

• eSIM profiles are bound to specific devices and cannot be moved to arbitrary hardware
• Remote provisioning requires device-level authentication
• There is no physical card to be replaced at a store
• An anonymous eSIM reduces the attack surface further since there is no account information to socially engineer

SIM swapping is one of the most damaging mobile attacks today. Protect yourself by moving away from SMS-based authentication and using eSIM technology that is inherently resistant to swap attacks.