Can someone read your text messages without access to your phone?

Have you ever had a feeling that someone else might be reading your private text messages?

It may sound odd, but attackers don’t even need physical access to your phone to read your texts. Through compromised accounts, synced messaging sessions, spyware, or SIM swap attacks that hijack a phone number, criminals could remotely access messages.

Key insights

• SIM swapping fraud are growing steadily – and so are losses. The FBI investigated 1,075 SIM swap attacks in 2023, with total losses nearing $50 million.
• According to Cifas, unauthorized SIM swaps increased by over 1,000%, rising from 289 cases in 2023 to nearly 3,000 in 2024.
• Mobile accounts are prime takeover targets. Cifas reports that 48% of account takeover cases involve mobile phone accounts.
• A hijacked phone number can unlock other accounts. Attackers may intercept verification codes and reset passwords for other services.

These numbers illustrate why cybercriminals increasingly target mobile numbers. A compromised phone account can become a shortcut to many other services tied to that number.

The good news is that these situations usually leave warning signs.

SIM swap fraud is a growing concern

One of the most dangerous ways attackers can intercept text messages is through a SIM swap attack.

In this type of attack, a criminal persuades a mobile carrier to transfer your phone number to a SIM card they control. Once the transfer is complete, the attacker receives your calls and text messages instead of you.

This can allow them to intercept verification codes used to log in to accounts. Once they have the codes, they usually try to reset passwords or access services tied to your phone number.

This type of attack has been increasing in recent years. The FBI investigated more than 1,000 SIM swap attacks in a single year, while fraud prevention group Cifas reported a surge in unauthorized SIM swap cases reported by telecom providers.

One warning sign is if your phone suddenly loses cellular service even though your device appears to be working fine. In some cases, this can indicate that your number has been transferred to another SIM card.

Text messages vs messaging apps

It is important to distinguish between SMS text messages and direct messages sent through apps such as WhatsApp, iMessage, Telegram, or Signal.

Traditional SMS messages travel through your mobile carrier’s network, which is why SIM swap attacks can allow criminals to intercept them. Messaging apps work differently. Most use end-to-end encryption, which protects messages while they travel between devices.

However, attackers may still gain access to conversations if they compromise the account itself or connect another device to it.

For example, someone might read messages in an app if:

• login credentials are stolen
• another device is linked to the account
• the email account tied to the service is compromised
• malicious apps gain access to the phone

This is one reason mobile numbers remain such attractive targets. According to Cifas, nearly half of account takeover cases involve mobile phone accounts, which attackers can use to access other services tied to that number.

Security alerts or login notifications you did not request

Unexpected security alerts are another possible indicator that someone is trying to access your messages.

Many services send notifications when a new device logs into an account or when someone requests verification codes.

Examples include messages such as:

• “New device logged into your account”
• “Verification code requested”
• “Password reset initiated”

If these alerts appear without you triggering them, someone may be trying to gain access to your accounts or intercept authentication codes sent via SMS.

Your contacts receive messages you did not send

Sometimes the first sign of a compromised messaging account comes from other people.

If friends or coworkers mention strange messages you supposedly sent, an attacker may have gained access to your messaging account.

Criminals often use compromised accounts to:

• impersonate the victim
• send phishing links
• request money
• promote scams through trusted conversations

Because the messages appear to come from someone familiar, recipients are more likely to trust them.

Unusual phone behavior or suspicious apps

In some cases, spyware or malicious apps installed on a device may capture messages or other activity.

These apps can run silently in the background and transmit information to external servers.

Possible warning signs include:

• sudden battery drain
• unexplained increases in data usage
• unfamiliar apps with extensive permissions

While these symptoms do not always indicate spyware, they are worth investigating if they appear alongside other unusual activity.

What to do if you suspect someone is reading your text messages

If you believe your messages or phone number may be compromised, taking action quickly can limit the damage.

Start by securing the accounts most likely to be targeted.

Change your passwords immediately
Update the passwords for email, messaging apps, and cloud accounts to strong, unique passphrases.

Check for extra safety measures with your mobile carrier

Some mobile carriers allow you to enable SIM protection features or account locks to prevent SIM swapping

Review active sessions and linked devices
Log out of devices you do not recognize in messaging apps and online accounts.

Contact your mobile carrier
If you suspect a SIM swap attempt, ask your provider to add a PIN or extra identity verification to your account.

Make 2FA stronger

 You can mitigate risks by switching to app-based authenticator apps instead of SMS-based 2FA.

Remove suspicious apps
Delete unknown applications and review app permissions on your phone.

Use mobile security to detect spyware and malicious apps
A dedicated mobile security solution can help detect malware or spyware that may be monitoring activity on your device. Bitdefender Mobile Security for Android and iOS provides real-time protection by scanning apps, blocking malicious downloads, and stopping phishing pages before they can steal credentials or install spyware.

Its Web Protection and Scam Alert features help block malicious links and suspicious websites often used in phishing campaigns that lead to account compromise.

Monitor your exposed personal data
Because phone numbers are often used in account recovery and SIM swap attacks, it’s important to know if your information has been exposed online. Bitdefender Digital Identity Protection helps you discover where your personal data appears on the internet and alerts you if it shows up in breaches or suspicious places that could lead to account takeover or identity theft.

You can also analyze suspicious messages or links using Bitdefender Scamio or verify URLs with Bitdefender Link Checker before interacting with them.

FAQs

Can someone read your messages without you knowing on your iPhone?

Yes, it can happen. If someone gains access to your Apple ID, they may be able to view messages synced through iMessage on another Apple device such as a Mac, iPad, or another iPhone. Messages could also be exposed if your Apple account credentials are compromised or if iCloud backups are accessed.

Checking your Apple ID devices list and security settings can help identify unfamiliar access.

How do you know if someone is reading your text messages from another phone?

There is usually no direct notification, but several warning signs may appear. These can include unknown devices linked to messaging apps, unexpected login alerts, missing messages, or contacts reporting messages you did not send. In some cases, SIM swap attacks or compromised messaging accounts allow attackers to receive messages on another device.

Can someone watch you through your phone without you knowing?

Yes, it is possible if your device is infected with spyware or a malicious app that gains access to your camera or microphone. Some types of malware are designed to secretly activate device sensors, capture photos or video, or monitor activity in the background without obvious signs. If you are concerned about this type of threat, you can learn more about the warning signs and protective steps in this dedicated guide.

Keeping your phone updated, reviewing app permissions regularly, and avoiding suspicious downloads can significantly reduce the risk.