What are the risks of using phone numbers for identity verification?
Posted: Wed May 21, 2025 5:30 am
While phone numbers are a common and convenient tool for identity verification, especially through two-factor authentication (2FA) via SMS or voice calls, they come with several inherent risks that can compromise user security and privacy. Relying solely on phone numbers for identity verification can create vulnerabilities that malicious actors can exploit.
Here are the major risks of using phone numbers for identity verification:
SIM Swapping / SIM Jacking:
Description: This is perhaps the most critical threat. An denmark number database attacker tricks your mobile carrier into transferring your phone number to a new SIM card under their control. This is usually done through social engineering (impersonating you) or by leveraging insider access at a mobile carrier.
Risk to Verification: Once the attacker controls your number, they receive all your incoming calls and SMS messages, including OTPs (One-Time Passwords) used for 2FA and password reset links. This allows them to bypass identity verification, reset passwords, and gain unauthorized access to numerous online accounts (email, banking, social media, cryptocurrency, etc.).
Phone Number Recycling:
Description: When a mobile number is deactivated by its original owner, it eventually enters a dormancy period and is then re-assigned to a new subscriber.
Risk to Verification: If the previous owner of the recycled number did not update their contact information on various online services, the new owner could potentially receive SMS OTPs or password reset links intended for the previous owner. This can lead to unintentional (or intentional) access to the previous owner's accounts, causing significant privacy breaches and potential account takeovers.
SMS Interception and Phishing:
Description: While less common than SIM swapping, SMS messages are generally not encrypted end-to-end and can, in some rare cases, be intercepted by sophisticated attackers. More commonly, attackers use phishing techniques, sending fake login pages or malicious links via SMS (smishing) to trick users into entering their credentials and OTPs directly.
Here are the major risks of using phone numbers for identity verification:
SIM Swapping / SIM Jacking:
Description: This is perhaps the most critical threat. An denmark number database attacker tricks your mobile carrier into transferring your phone number to a new SIM card under their control. This is usually done through social engineering (impersonating you) or by leveraging insider access at a mobile carrier.
Risk to Verification: Once the attacker controls your number, they receive all your incoming calls and SMS messages, including OTPs (One-Time Passwords) used for 2FA and password reset links. This allows them to bypass identity verification, reset passwords, and gain unauthorized access to numerous online accounts (email, banking, social media, cryptocurrency, etc.).
Phone Number Recycling:
Description: When a mobile number is deactivated by its original owner, it eventually enters a dormancy period and is then re-assigned to a new subscriber.
Risk to Verification: If the previous owner of the recycled number did not update their contact information on various online services, the new owner could potentially receive SMS OTPs or password reset links intended for the previous owner. This can lead to unintentional (or intentional) access to the previous owner's accounts, causing significant privacy breaches and potential account takeovers.
SMS Interception and Phishing:
Description: While less common than SIM swapping, SMS messages are generally not encrypted end-to-end and can, in some rare cases, be intercepted by sophisticated attackers. More commonly, attackers use phishing techniques, sending fake login pages or malicious links via SMS (smishing) to trick users into entering their credentials and OTPs directly.