10 Serious Risks of Giving Out Your Cell Phone Number

Hey there! As a cybersecurity professional with over 15 years in the industry, I need to have a frank conversation about your cell phone number. I know those 10 digits seem harmless, but I promise you – that number contains a goldmine of sensitive information that you need to protect.

Handing it out casually or posting it publicly can open you up to a whole world of potential fraud, harassment, and identity theft. Scammers are absolutely ruthless when it comes to exploiting cell numbers these days.

In this comprehensive guide, I‘ll walk you through the top 10 dangers of sharing your mobile number so you can see just how much damage the wrong people can do. My hope is that by the end, you‘ll be far more cautious and proactive about keeping your number private. Let‘s dive in!

When Should You Actually Share Your Number?

Before we get into the risks, it‘s important to clarify that there are some legitimate situations where providing your cell number is necessary. You generally want to stick to trusted businesses and close contacts.

Here are a few examples of when it’s typically okay to give out your number:

• Healthcare providers for appointment reminders
• Insurance and banking representatives
• HR staff and recruiters during the job application process
• Background check services for employment or tenancy
• Close friends and family members
• Classified ad purchasers if needed to facilitate the transaction

Besides those cases, I‘d advise keeping it private, including on social media profiles. You just never know where that number could end up once it‘s out there.

Now let‘s get into the main event – the top threats you face by oversharing your phone number.

1. Endless Robocalls and Spam

One of the biggest nuisances that comes with a leaked number is getting plagued by spam calls and robocalls at all hours.

• Robocalls alone make up a staggering 50% of all mobile phone calls in 2022 according to the National Consumer Law Center and other data.

• The FCC also estimates that over 33 million scam robocalls are made daily in the US.

Once these aggressive auto-dialers get your number, expect a barrage of unsolicited calls trying to sell you warranties, request donations, collect fake debts, gather personal information, or spread malware to your device.

Even when these spam calls aren‘t overtly harmful, they are incredibly disruptive to your daily life. The constant interruption can make you less productive at work, ruin your downtime, and even disrupt your sleep.

And here‘s the kicker – even taking steps to block callers often does little to deter them in the long run. Tricky spammers regularly spoof new numbers to bypass block lists. I‘d rank rampant robocalls and spam as the most unavoidable risk of handing out your mobile number.

2. SMS Phishing Attempts (Smishing)

In addition to phone calls, a leaked cell number also opens the door to SMS phishing attempts, also known as smishing. This scam tactic has absolutely exploded in recent years.

• FTC data shows that losses to text message scams rose to $59 million in 2021, up from just $10 million in 2019.

Why has smishing gotten so popular with criminals? For a few reasons:

• People are far more likely to open and respond to texts than sketchy emails. We tend to inherently trust messages that pop up on our phones.

• Mobile numbers are far easier to obtain at scale than email addresses. There are only so many possible cell number combinations versus infinite email addresses.

• SMS texts are not marked as being from a verified source, making spoofing much easier.

Scammers will text you pretending there is a problem with one of your accounts that requires urgent attention, often posing as Amazon, your bank, or a government agency. The message urges you to visit a website to verify recent charges or log back into your account.

If you click that link and enter your login credentials, the scammers immediately have access to sensitive personal and financial information. I can‘t emphasize enough what a massive threat smishing has become – always verify any texts before clicking unfamiliar links or sharing data.

3. The Rising Threat of SIM Swapping

SIM swapping refers to social engineering-based identity theft where scammers convince your mobile carrier to transfer your number to a SIM card they control.

By porting your number to their own device, criminals gain access to any calls, texts, and two-factor authentication passcodes intended for you. This lets them easily reset the passwords on your online accounts and intercept any login verification texts.

According to research from SpyCloud:

• Reports of SIM swapping increased by over 600% from 2018 to 2020.
• Criminals netted $12 billion from SIM swap fraud in those two years alone.

Once SIM swapped, hackers can drain your financial accounts, access your email, impersonate you on social media – you name it. Given how reliant we‘ve become on cell numbers for account security, SIM swapping poses a massive threat.

4. The Public Shaming of Doxing

Doxing refers to publicly releasing someone‘s personal information like addresses, phone numbers, place of work, etc. without their consent. It‘s often used as a way to shame, intimidate, and silence people.

With your mobile number in hand, an angry stranger has an easy way to tie your identity to any embarrassing or defamatory information they want to post about you online.

And once that data is out there on the public internet, it becomes almost impossible to fully remove. Having been doxed before, I know how violating it feels – and a leaked phone number only makes it easier to be targeted.

5. Direct Account Hijacking

Because cell numbers are so commonly used for password recovery these days, your mobile number itself provides the keys to the kingdom for many of your online accounts. Even without clever social engineering, someone with your number can wreak havoc.

With your digits in hand, scammers can:

• Request password resets via text message for your email, social media, and even financial accounts.

• Call customer service pretending to be you, and use your number for verification.

• Intercept two-factor authentication codes sent via SMS to log into your accounts.

Research suggests a stolen mobile number can be even more valuable than passwords when it comes to account access:

• According to Verizon, 25% of users only use cell numbers as authentication when resetting passwords.

• Microsoft found that compromised mobile accounts were involved in 67% of successful nation-state cyber intrusions.

Keep your number away from cybercriminals, and you‘ll drastically reduce your risk of getting hacked.

6. The Threat of Blackmail and Extortion

If scammers are able to access any compromising or sensitive information about you, they may try to blackmail and extort you by threatening to make that information public. This could include:

• Embarrassing photos, videos, or text conversations
• Evidence of "inappropriate" online activity
• Confidential business or workplace data

The potential release of damaging information can be terrifying, and hackers know that. They will demand large ransom payments in cryptocurrency from victims, often hundreds or thousands of dollars worth.

And even giving in to their demands is no guarantee they‘ll delete the data. Once criminals have that kind of leverage over you, it‘s best not to engage with them whatsoever. Don‘t put yourself in that position if you can avoid it.

7. You‘ll Unwittingly Put Contacts at Risk Too

It‘s not just your own identity and accounts at risk when you hand out your number freely – it puts your friends and family in the crosshairs as well.

A common scam approach is for hackers to send texts or place calls to your saved contacts while posing as YOU. They may claim you lost your wallet while traveling, need bail money urgently, or give some other pressing emergency rationale. Out of concern for you, the victims send money before realizing it‘s a scam.

According to FCC data, losses to fake emergency scam texts doubled between 2020 and 2021 to $42 million. Don‘t put your loved ones in that position by letting strangers get ahold of your number.

8. Enabling Harassment and Abuse

I hate to say it, but cell numbers can also be used to enable harassment, cyberbullying, stalking, and other disturbing invasions of privacy by abusive individuals.

With access to your number, stalkers can:

• Constantly call and send threatening or explicit texts even if you block them.

• Sign up for services that announce incoming caller names, exposing your number.

• Potentially access GPS location data depending on your phone settings and apps.

• Look up your home address via reverse phone lookups.

• Install spyware that tracks your phone‘s location based on the number.

Online harassers can also use your number to tie any personal info they find to you or trick site admins into giving away private account data. Don‘t let your number fall into the hands of someone wishing to hurt or control you.

9. Highly Effective Social Engineering

Social engineering refers to manipulating people into giving away confidential information. While hacking often relies on technical intrusion directly into accounts, cunning social engineering lets criminals bypass security through persuasion and deception.

With your cell number in hand, thieves can convincingly pose as you over the phone with companies like your bank, phone carrier, tech providers, and more. When asked to "verify your identity," the criminals confirm using your cell number, then seek access to account data, request changes, and perpetrate fraud.

Some alarming stats on how easily people fall for mobile social engineering:

• Verizon found that 1 in 3 adults were tricked into giving away sensitive data via mobile scam calls.

• Google saw a 650% increase in government-backed social engineering attempts via mobile numbers during the pandemic.

Don‘t let anyone get their hands on the key that unlocks so much of your sensitive personal data.

10. Marketing Calls and Data Sharing

While not overtly malicious, getting bombarded by telemarketers is one more annoyance that comes with overexposure of your cell number. Data brokers sell mobile numbers legally to all sorts of companies.

Before you know it, you could start getting calls from sales reps pushing insurance plans, cruises, or dubious payday loans. It‘s disruptive and frustrating.

Certain unscrupulous brokers may also sell your number directly to criminal groups and scammers involved in the risks outlined above. Your number is likely to end up on dozens of call lists once it enters the data broker system.

Okay, My Number is Compromised – Now What?

If you‘ve realized your cell phone number has likely fallen into the wrong hands, don‘t panic. There are steps you can take to get back on track quickly:

Contact your mobile provider – Alert them to suspected fraud, and inquire about increased security options like passcodes to modify your account or blocking re-routing of calls/texts.

Change passwords – Immediately reset all passwords for your sensitive online accounts, avoiding sending codes to your phone number when possible.

Review privacy settings – Double check your social media profiles and other sites to limit personal info access.

Enable two-factor authentication – Require secondary log-in methods beyond SMS texts to enhance security.

Check credit reports – Identity thieves may use your number to open unauthorized credit in your name.

Use a data removal service – Have them wipe your number from public people search sites.

Warn contacts – Let family and friends know not to trust texts from your number requesting money or info.

Consider changing your number – If all else fails, leaving your number behind fully can help halt persistent fraud.

Handing out your cell number does carry risks – but you‘re far from powerless in fighting back against mobile scams. Just stay vigilant in keeping tabs on your accounts and don‘t hesitate to flag suspicious activity.

Stay smart out there! Let me know if you have any other mobile security questions.