Our Threat Intelligence team has uncovered yet another huge leak of WhatsApp phone numbers. A hacker recently posted on the Dark Web, claiming to have over one billion numbers for sale.
This comes after the other huge leak in 2023, where over 500 million numbers were breached.
While many people might think, “It’s just a phone number—what’s the harm?” the reality is that a leaked phone number can be the first step in a much larger cyber attack. Hackers use these numbers in various ways to exploit individuals, steal personal data, and even take over accounts.
How Do Hackers Use Stolen Phone Numbers?
Phishing and Smishing Attacks
- Targeted phishing – Hackers craft convincing messages posing as banks, delivery services, or tech companies.
- Smishing (SMS phishing) – Fake texts trick victims into clicking malicious links or entering login credentials.
- Personalised attacks – If linked to other breached data such as a name, email, or location, scams become even more convincing.
Credential Stuffing and Account Recovery Abuse
Many services use phone numbers for authentication, making them a key target:
- Hackers attempt to log in to accounts where phone-based authentication is enabled.
- They trigger password reset requests, potentially gaining access to emails, social media, and banking apps.
Social Engineering and Impersonation Scams
- Account takeover attempts – Hackers call customer support, pretending to be the victim, to reset passwords.
- Scams targeting friends and family – Fake messages such as "I lost my phone, send money to this number" trick contacts into sending cash.
- Voice cloning via AI – If hackers have recorded samples, they can generate convincing fake voices for scams.
SIM Swapping – A Gateway to Full Account Takeovers
Phone number leaks can enable SIM swapping, where attackers hijack a mobile number by convincing phone providers to transfer it to a new SIM.
- Mobile carrier attacks – Hackers research a provider and use social engineering to request a SIM swap.
- Bypassing security questions – If they have other breached data, such as date of birth or address, they can trick providers into handing over control.
Targeted Messaging App Exploitation
Since phone numbers are linked to WhatsApp, Telegram, and Signal, hackers can:
- Send scam messages directly to contacts.
- Attempt WhatsApp takeovers by tricking users into revealing security codes.
Malware Distribution and Spyware Attacks
- Fake system updates – Attackers send malicious SMS messages claiming a phone needs an urgent update.
- Targeted spyware – If linked to high-profile individuals, breached numbers could be used for advanced surveillance attacks.
Why This Matters
A stolen phone number is not just a random data point—it can be the foundation of a highly targeted cyber attack. Hackers use these numbers to build a victim profile, leading to financial fraud, identity theft, and account takeovers.
How to Protect Yourself
- Be cautious of unexpected texts or calls asking for information.
- Enable two-factor authentication (2FA) on all accounts.
- Never share one-time passcodes or verification texts.
- Use strong passwords and avoid reusing them across accounts.
At DynaRisk, our Cyber Xpert platform helps users monitor for data breaches, including leaked phone numbers, so they can take action before an attack escalates.
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