What Can Hackers Do With Your Phone Number?

You might think that a threat actor only having your phone number isn’t dangerous, but it can be, which is why it’s important to learn what hackers can do with it. With just your phone number, hackers can send you phishing texts and calls, flood your phone with spam calls, spoof your phone number, swap your SIM card and even steal your personal information. 

Continue reading to learn more about what hackers can do with your phone number and tips for keeping yourself safe. 

What hackers can do with your phone number

Here’s what a hacker can do with only your phone number. 

Target you with phishing attacks

Phishing attacks occur when threat actors attempt to persuade victims into revealing personal information. This type of attack can happen through email, text messages and phone calls. If a threat actor knew your phone number, they could begin targeting you with phishing attempts through texts, phone calls or both. If you fall for a phishing scam, you may end up giving away personal information that the bad actor can use to compromise your online accounts or steal your identity.  

Spam you with calls

Spam calls can be annoying, especially if you don’t have these calls blocked on your phone. If your phone number is a part of a data breach, the number of spam calls you receive may increase. While some of these calls can be from legitimate telemarketers, they can also come from threat actors with malicious intentions to steal your information. 

Spoof your number

If a threat actor knows your phone number, they could spoof it and target the people you know and strangers with phishing attempts. Typically, when you receive a phone call, the caller ID appears letting you know who’s calling you. If your phone number is spoofed, it means a threat actor is pretending to be you by displaying your phone number. This can be dangerous for your family members and friends because they’ll think you’re the one who is calling them. If a threat actor is spoofing your phone number to target strangers, it can also lead to receiving angry texts and calls from people who think you’re spamming them. 

Swap your SIM to their phone

A SIM card is a unique identification number given to you by your mobile carrier. SIM cards contain information about your available data, network plan, text messages, phone number and contacts. Through a cyber attack called SIM swap fraud, threat actors can convince your mobile carrier to port your number to a new SIM card. Usually, they pretend to be you by saying you lost your phone or had it stolen. If a mobile carrier swaps your SIM card, the threat actor will be able to receive all of your phone calls and messages. This can be dangerous since cybercriminals can use your phone number to receive your SMS Two-Factor Authentication (2FA) codes, making it easy for them to gain access to your accounts. 

How to stay safe from hackers who have your phone number

Here’s what you can do to keep yourself safe if a threat actor has your phone number.

Secure your SIM card

You can secure your SIM card by setting up a SIM lock, which requires a PIN. Here’s how to set up a SIM lock on your iPhone or Android. 

Important Disclaimer: When setting up a SIM lock be careful to not enter the SIM PIN incorrectly three times as this will cause your mobile service to stop working – meaning you’ll have to contact your mobile carrier to fix your service. 

How to set up a SIM lock on an iPhone

1. Go to Settings
2. Tap Cellular > SIM PIN
3. Toggle the button next to SIM PIN to enable it
4. Enter your mobile carrier’s default PIN which is usually “1111” (double-check with your mobile carrier before entering this default PIN)
5. Once it’s enabled, tap Change PIN
6. Enter the default PIN again, then enter the new PIN you want to use to unlock your SIM card

How to set up a SIM lock on an Android

1. Go to Settings
2. Tap Security & Privacy > More security settings > SIM card lock
3. Toggle the button next to Lock SIM card to enable it
4. Enter your mobile carrier’s default PIN which is usually “1111” (double-check with your mobile carrier before entering this default PIN)
5. Once it’s enabled, tap Change SIM PIN
6. Enter the default PIN again, then enter the new PIN you want to use to unlock your SIM card

Block spam calls

Blocking spam calls can help protect you from falling victim to scammers. While it’s not possible to block ALL spam calls, it is possible to block most of them. Here are a few tips you can follow to block most spam calls: 

• Contact your mobile carrier to see if it offers call-blocking services
• Get a spam-filtering app such as Truecaller, Roboshield or Hiya
• Sign up for the National Do Not Call Registry by going to donotcall.gov 

Don’t click unsolicited links and attachments in messages

If you receive any sort of message containing a link or attachment, don’t click it. It’s a cybersecurity best practice to never click on unsolicited links and attachments because they could contain malware that leads to your personal information being stolen. 

Avoid using SMS as an MFA method

Most websites and applications give users the option to choose between different Multi-Factor Authentication (MFA) methods. Many people tend to not enable MFA at all or only enable SMS authentication. While SMS authentication is better than no additional authentication, it can be dangerous if a threat actor successfully swaps your SIM card to their phone. Instead, it’s best to use other types of MFA such as:

• Authenticator apps
• Hardware security keys
• Passkeys
• Biometric authentication

Protect your phone number against hackers

Your phone number can be used in various ways by hackers to steal your personal information and compromise your online accounts. Taking preventive measures such as locking your SIM card, blocking spam calls, not clicking on unsolicited links and attachments, and using other MFA methods besides SMS can make all the difference in keeping you and your data safe.