What to Dial to See if Your Phone Is Hacked

Our smartphones hold a treasure trove of sensitive information, from personal conversations and photos to financial data and online accounts.

That makes them a prime target for hackers, and the consequences of compromise can range from identity theft to serious personal safety risks.

While there’s no single number you can dial to instantly know if your phone is hacked, there are specialized codes known as USSD (Unstructured Supplementary Service Data) codes that can reveal clues about potential compromises.

These codes let you query your phone’s settings directly and uncover signs of tampering or unauthorized activity.

In this article, we’ll cover the specific codes to use and explore what other signs to watch out for.

What Are USSD Codes?

Think of USSD codes as your phone’s secret language.

These shortcodes, typically starting with *# and ending with #, are quick commands you can use to communicate directly with your mobile network provider.

You’re probably familiar with some common uses of USSD codes, like checking your data usage or airtime balance.

But here’s the thing: USSD codes can also reveal clues about unusual activity on your phone — the kind that might be caused by a hacker.

While these codes don’t provide a definitive diagnosis, they offer a window into potential security issues. Think of them as warning lights on your dashboard; they might alert you to a problem, but further investigation is required to confirm if your phone has truly been hacked.

How to use USSD codes

1. Open your phone’s dialer app.
2. Enter the code exactly as shown in the sections below.
3. Press the call button.
4. Information will appear as a pop-up message on your screen.

ℹ️ The appearance and exact output of these codes may have slight variations depending on your service provider and phone model.

Common USSD Codes to Check for Phone Hacking

*#21# – Check unconditional call forwarding

Dial *#21# to check whether all incoming calls and texts are being redirected to another number — regardless of whether your phone is on, off, or in use. If forwarding is active, the destination number will be displayed.

Good to know:

• Use this number to verify whether someone has activated call forwarding without your knowledge.
• You can also check your own call forwarding setup (in case you previously activated it and forgot).

Fig 1: Checking unconditional call forwarding.

*#61# – Check forwarding when you don’t answer

Dial *#61# to check if calls are being forwarded to another number when you don’t answer after a certain number of rings. It will display the destination number if one is set.

Good to know:

• Scammers can use this type of call forwarding to silently redirect your unanswered calls and verification texts to a number they control.
• Because your phone still rings as normal, this type of forwarding can go unnoticed for a long time.

Fig 2. Checking unanswered call forwarding.

*#62# – Check forwarding when out of reach

Dial *#62# to check whether calls are being diverted when your phone has no signal or is switched off. It will display the forwarding number if one is active.

Good to know:

• Hackers can use this setting to intercept calls in situations where you’d naturally assume the call simply didn’t connect.
• Because your phone never rings and no missed call is recorded, this type of forwarding is one of the hardest to detect — and for that reason, one of the more attractive options for someone trying to intercept your calls without raising suspicion.

Fig 3. Checking out of reach call forwarding.

*#67# – Check forwarding when your line is busy

Dial *#67# to check whether calls are being redirected to another number when your line is already in use. It will display the forwarding number if one is set.

Good to know:

• Use it to verify whether someone has set up forwarding that only activates when you’re on another call. A tactic that can be hard to notice since your phone appears to be working normally.
• This number distinguishes between busy-state forwarding and other forwarding types, which *#21# won’t separate out on its own.

Fig 4. Checking busy call forwarding.

*#004# – Check all conditional forwarding at once

Dial *#004# to display the status of all conditional call forwarding settings simultaneously — covering unanswered, unreachable, and busy scenarios in a single query.

Good to know:

• This is a useful shortcut if you want a fast overview without running *#61#, *#62#, and *#67# separately.
• It’s also a good first check if you suspect something is wrong but aren’t sure which type of forwarding may have been tampered with.

Fig 5.Checking conditional call forwarding.

##002# – Disable all call forwarding

Dial ##002# to turn off all active call forwarding settings at once. This is the quickest way to reset everything to default if you find unexpected forwarding during your checks.

Good to know:

• If any of the codes above return an unrecognized number, dial this immediately to cut off the diversion.
• You can also use this after you’ve set up temporary call forwarding yourself and want to return to normal.

Fig 6. Disabling call forwarding

*#06# – Check your IMEI number

Dial *#06# to display your phone’s unique IMEI (International Mobile Equipment Identity) — a 15-digit number that identifies your specific device, similar to a serial number.

Good to know:

• If the displayed IMEI differs from the original (you can usually find this printed on the back of the box your phone came in), it may indicate unauthorized tampering or cloning.
• If your phone is stolen, reporting this number to your carrier allows them to block the device from accessing their network.

Fig 7. Checking IMEI

*#*#4636#*#* or *#*#197328640#*#* – Hidden diagnostics menu (Android only)

Dial *#*#4636#*#* or *#*#197328640#*#* to open a hidden diagnostics panel on most Android devices, containing technical information about your phone, battery, app usage, and Wi-Fi status.

Good to know:

• Review the app list under usage statistics. This can reveal unfamiliar apps running in the background and consuming resources.
• This menu is intended for advanced users. Avoid changing any settings unless you know what they do, and be aware that the layout varies across Android models.

Fig 8. Checking Usage Statistics on Android

*3001#12345#* – Field Test Mode (iPhone only)

Dial *3001#12345#* to launch a technical diagnostic panel on iPhones showing signal strength, connection details, and carrier data.

Good to know:

• Can reveal unusual connection behavior that may warrant further investigation.
• Note that this is an advanced diagnostic tool — most users won’t need to act on what they see here without guidance from a technician or support team.

Fig 9. Checking the field test mode dashboard

*#*#232338#*#* – View Wi-Fi MAC address (Android only)

Dial *#*#232338#*#* to display your device’s unique MAC (Media Access Control) address for its Wi-Fi hardware.

Good to know:

• If you manage your own router, compare this address against the devices authorized on your network to confirm your phone is the only one using your connection.
• If an unknown device with a suspiciously similar MAC address appears on your network, it could indicate someone is attempting to spoof your device to intercept data.

Other Indicators of a Hacked Phone

Beyond USSD codes, your phone often exhibits tell-tale signs if it has been compromised — and it’s more common than most people assume.

According to Certo’s 2025 Mobile Security Roundup, which analyzed nearly 600,000 device scans, almost 7% of devices showed medium or high security threats. Here are some common red flags to watch out for:

Unusual battery drain

If your battery is depleting faster than normal — even during light use — it could be a sign that something is running in the background without your knowledge. Spyware and malware consume power continuously as they monitor your activity and transmit data.

Before drawing conclusions, rule out obvious causes like a recently updated app or an aging battery. If nothing explains it, it’s worth investigating further.

Poor performance

A phone that’s suddenly slow to open apps, laggy during normal tasks, or crashing more than usual may have more going on than a software glitch. Malicious software can quietly consume your device’s processing power, leaving less available for everything else.

If the slowdown is persistent and unexplained by a recent update or low storage, treat it as a red flag rather than a minor annoyance.

Unrecognized apps

Finding an app on your phone that you don’t remember installing is one of the clearest warning signs of compromise. Hackers often disguise malicious software as mundane utilities — file managers, flashlight apps, or system tools — to avoid drawing attention.

Regularly review your installed apps and remove anything unfamiliar. If you’re unsure about an app, search the name before deleting.

High data usage

An unexplained spike in your monthly data consumption can be one of the subtler signs that something is wrong. Spyware and malware often work by transmitting data in the background — sending your messages, photos, or location to a remote server without you knowing.

Check your data usage breakdown in your phone’s settings. If an unfamiliar app is consuming a significant amount, that warrants a closer look.

What to Do If You Suspect Your Phone Is Hacked

If you find yourself in a situation like Alex’s, and the USSD codes or other signs point towards the possibility of your phone being hacked, taking swift action is crucial.

If you’re checking these codes because you suspect someone close to you is monitoring your phone, you’re not alone. This is more common than many people realize. Certo has compiled a list of support resources if you need help beyond the steps below.

• Change passwords: Immediately reset passwords for all sensitive accounts. This includes email, banking, social media, and other accounts holding important personal or financial data. Use unique, strong passwords for each account.
• System updates: Keep your phone’s operating system and apps updated with the latest security patches.
• Download with care: Stick to downloading apps from official app stores (the Apple App Store or Google Play Store) and research apps before installing them.
• Avoid clicking strange links: Never click on links in texts or emails from unknown senders. These can lead to malware or phishing scams.
• Factory reset: In persistent or severe cases, a factory reset might be necessary. This erases all data and returns your phone to its original factory settings. Before doing this, back up any essential data you want to preserve.
• Run security scan: Install a trusted antivirus/anti-malware app on your phone (if you don’t have one already). Run a full scan to detect and remove any malicious software a hacker may have slipped onto your device.

Beyond USSD codes: Comprehensive threat detection with Certo

While USSD codes can offer valuable clues, they only scratch the surface when it comes to cybersecurity.

For robust defense against phone hacking, consider dedicated security apps like Certo AntiSpy. Our mobile security solutions offer advantages like:

• Deeper scans: Go beyond simple settings checks and thoroughly examine your device for a wide array of malware, spyware, keyloggers and other threats that could be hidden from basic tools – regardless of whether you have an iPhone or Android device.
• Protect WiFi: Helps you stay safe online by analyzing your current network for signs of unauthorized monitoring, router vulnerabilities and other threats.
• Tailored for your OS: Our apps are designed specifically for the unique security needs of Android and iOS, ensuring you get the best protection for your particular device.

Fig 10. Securing a phone with Certo AntiSpy for Android.

Final Thoughts

Protecting your phone from hacking requires a multi-faceted approach.

While no single method guarantees complete security, a combination of tools and vigilance offers the strongest defense.

USSD codes provide initial clues, but being aware of common red flags like strange device behavior is equally important.

Consider using a dedicated security app like Certo AntiSpy for peace of mind and the best chance of detecting even sophisticated compromises.