What is an OTP Bot (and How To Protect Yourself)

In this article, we will discuss what an OTP bot is, signs that you can look out for to identify it, and how to protect yourself should you need to.

We will also discuss how they work and their primary purpose.

What is an OTP Bot?

An OTP bot is short for a one-time password bot. They are automated programmes which potential cyber attackers can use to extract one-time authentication passwords from users. They do this by sending an authentication code via email, SMS, or even an authentication app.

Once the hacker has received the authentication code, they can perform unauthorised actions (such as transactions) from multi-factor authenticated protected accounts.

How Does an OTP Bot Work?

These bots’ work can be pretty complex, so splitting it into various steps is more manageable.

Step 1: Giving Information

Firstly, the cybercriminal will give the victim’s information to a bot. This can be a username for a website, an email address, or some other form of digital information.

The purpose is to access the victim’s accounts, transfer funds or money to another account, take personal information, or perhaps leak sensitive data.

Step 2: Posing as a Company

The cyber attacker will then give the bot the victim’s mobile phone number and the name of their bank (if they are hacking their bank account, for example).

The bot is then programmed to initiate a call to the victim, posing as the bank.

The victim, most likely being none the wiser, will then verify it is themselves to the bot (posing as a bank worker) to hand over some multi-factor authentication information for the bot to access their bank account.

This information could be one of the security questions that they set up. For instance, their mother’s maiden name, the name of their first childhood pet, the name of the primary school they attended, etc.

To appear more legitimate, OTP bots will call with a sense of urgency, such as letting the customer know that someone has tried to access their bank account and that they need to give them access to prevent any fraud from occurring, for instance.

This creates a sense of panic in the victim, who will naturally give out information without questioning whether the call may be legitimate.

Step 3: The Final Blow

While the panicked victim is handing over the information, the bot will take this time to distract the victim, perhaps by pretending to place them on hold. In contrast, the victim has already sent the necessary verification codes over.

During this time, the attacker will intercept and take out any money or funds while the victim is none the wiser about what is happening.

Methods Employed by OTP Bots

As well as being able to access bank accounts like the method listed above, OTP bots utilise several other methods to gather data for hackers. These will be listed below.


Phishing is one of the most popular ways OTP bots can gather personal information. Phishing is a form of social engineering where attackers try to deceive people into giving away sensitive information or clicking a bad link to install malware on their devices. OTP bots are notorious for using phishing by posing as a legitimate company, business, organisation or even a person to gain the victim’s trust before hacking their information and data.

By doing this, they impersonate the organisation before prompting the victim to give them a one-time password or code before hacking into their accounts.


Any devices already infected with malware are more likely to be unable to identify a threat actor, such as an OTP bot.

This is because the device will already be infected (perhaps from a previous phishing attack), so the device’s security systems will be down or at least compromised to an extent.

The OTP bot will likely have easy access to the device.

This is one of the more dangerous ways for the victim to deal with because the security of OTPs has already been compromised before they have even been sent to the user.

SMS Attacks

This can happen when an OTP bot, posing as a mobile phone provider, can access a victim’s phone via SMS or text.

Similar to the bank example above, an OTP bot can pose as a mobile phone provider employee, prompting the victim to give them a one-time code that has been sent to their phone.

The victims receive either text messages or a phone call with a code, which they unknowingly provide to the bot.

The bot will often say that their phone account or SIM card has been compromised, so they must transfer their SIM card to a different device.

Now that the hackers can access the victim’s phone, they can simply enter the OTP code and intercept any further passcodes sent via SMS, thus gaining entry into the victim’s phone.

How To Protect Yourself from OTP Bots

As discussed above, OTP bots can be very dangerous, as they can gain a victim’s trust by posing as somebody else.

Because they are so dangerous, some steps and precautions can be taken to protect yourself against them.

These will be discussed in further detail below.

Set Up Delays

In this age of wanting more information quicker than ever, setting up a delay system for any text message or email coming through seems counter-productive.

Indeed, that would just put off customers or employees, right?


Setting up exponential delays could help to save you from an OTP bot attack.

The way that this works is pretty simple. Setting up an exponential delay between requests made with the same phone number effectively prevents bulk sending and multi-factor authentication spamming, sometimes known as MFA bombing.

If there is a lengthy delay – even just ten minutes – between each audit attempt on your devices every time someone tries to access your account, this can significantly put hackers off.

It may not necessarily prevent fraud altogether, but it can certainly put hackers off enough by wasting their time – they may find it takes too long to access your account and will try their luck elsewhere.

Bot Detection Software

Using systems to help identify and detect bots in the first place can also be an excellent method to prevent OTP bombing.

For example. Using a standard system such as a CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is a fantastic way to sieve out bots.

You will occasionally see these tests when trying to log in or access a site to prove that you’re not a bot.

They will often show a grid-based picture and ask you to click on every street light, car, or tree, for example, in the picture.

Bots can struggle to identify and process this information, so adding a CAPTCHA is an excellent example of bot detection software that can help you stave off the majority of bots.

VPN Monitoring

Another way you can protect yourself against OTP bots is by monitoring virtual private networks (VPNs).

While there are many positive reasons for using a VPN, hackers are almo
st guaranteed to use one for all the wrong reasons.

Utilising software such as VPN blockers can help you out in this way.

Monitor OTP Conversion Rates

If you are conscious of how hackers seem to be able to keep getting information and how one-time password codes are still being sent through, then it might be worth setting up an automated tool (or employing someone) to monitor OTP conversion rates.

Doing this lets you see and analyse the number of OTP codes being sent out. You can then create an alert within your internal monitoring tool for the authentication conversion rate. Examples include the number of OTPs validated by end users, or the number of OTPs sent out in the first place.

You can then see if this rate begins to drop at an unusual level, increase massively, or where the requests are coming from.

For example, if the requests are coming from an unknown location or country, you can trigger an alert for a manual review to see why, how and if they are OTP bots,s and hackers attempting to harvest data.

Pre-Audit Systems

A bit like the bot detection software such as the CAPTCHA listed above, setting up a pre-audit system can also help you out when it comes to identifying OTP bots.

A common mistake many people make is simply sending an SMS as their only authentication method.

It does have its advantages, such as adding an extra step to the verification process (which can be seen as slightly frustrating for legitimate users). Still, it can help deter cyber criminals, potential hackers, and bots.

But you can also add further steps, such as asking for an email address before a phone number is given.

Implementing that extra step, or 2FA codes, is becoming more popular and helping to increase people’s safety online.

Additional IP Checks

Adding any extra checks on IP addresses, devices or user credentials whenever a user creates an account (whether a new user altogether or an existing user creating a new account) can help put off OTP bots.

This is because it helps to identify any suspicious behaviour and take action before the hacker can even request a message to be sent.

This is undoubtedly one of the more helpful suggestions you can implement, as it can help you greatly in the long run.

Significantly, you can limit the number of SMS request attempts from the same IP address or device. For instance, you can also include latency in the requests, such as one password reset per hour.

Set a Server Limit

Another way in which you can protect yourself from OTP bots is by setting a server limit. Make sure that whichever device you are concerned about – mobile phone, computer, laptop or tablet – does not send a message every set of seconds to the same mobile number range or prefix.

IP, device ID, or each user can set up these limits.

Similarly to other examples mentioned above, this can help deter any bots and potentially prevent any account takeovers by simply wasting the bot and hacker’s time.

Implement Geographical Permissions

You can also set up restrictions from requests from certain geographical countries. This can sometimes help to protect you against OTP bots.

The reasoning behind this essentially boils down to preventing spam. This means that for certain brands that are not present in various countries – let’s say that your business is not present in India, Peru, and South Africa – you could set up a blocker that prevents any requests from coming.

This does not exclude anyone from those countries who might be interested in your services. On the contrary, it simply turns off destinations not eligible for your services.

This means less time you have to worry about whether a request from a country you have no affiliation with (business-wise) could be legitimate or a scam – because you will not receive those requests anymore.

Additionally, you can also create blocks on specific country dialling codes. Again, suppose you have no business affiliation with certain countries. In that case, you can block any number beginning with those particular countries’ dialling codes, meaning that you will not receive any requests from any numbers starting with a dialling code of a country with which you have no business relations.

Update Your Devices Regularly

This does not mean you have to buy the latest Apple Mac or iPhone or take out a bank loan to get the latest gadgets!

Instead, it just means keeping up with your devices’ security needs.

For example, when was the last time you changed a password? Has your passcode for your smartphone always been the same? How about your email address? Does your password contain capitalised letters, specialised characters and numbers, or is it something as obvious to guess as ‘password123’?

In addition, downloading anti-virus software can also help you out. If your device is a few years old, it is likely more susceptible to viruses than a brand-new device.

If you can download new anti-virus software or any other software that can help protect your device, you should – after all, it is better to be safe than sorry.

The Importance of Strong Passwords

One of the most important ways you can protect yourself against OTP bots is by having strong passwords for all your devices.

For example, use the same password for many different accounts – from your social media accounts to your Apple Pay passcode to passwords for any bills or banking accounts or any financial services. You can be at risk of serious security breaches.

It is essential to have a strong password – recent research suggests that it would take a hacker 26 trillion (yes, trillion!) years to hack the most complicated level of password – one that is 18 characters long and contains numbers, a mixture of upper and lowercase letters and other special characters and symbols.

Compare this to the fact that hackers can instantly hack any password of just 11 numbers or even a 6-character password containing special characters, upper and lower case letters and numbers.

It is worth making the extra effort to complicate your passwords – as long as you have a password management tool to look after them or store them safely and securely.

You can even use random password generators, which typically give you 18+ character passwords with a mixture of all the above factors, making it even harder for hackers to access your accounts.

Can I Use an Authentication App?

Another good way of protecting yourself from OTP bots is through an authentication app.

This does not always mean that you have to rely on various multi-factor authentication (MFA) methods or two-factor authentication (2FA) methods, and it also means that you can avoid being sent time-sensitive one-time passcodes to your device all of the time.

Instead, by using an authenticator app such as Authy or Google Authenticator, those apps will generate a one-time passcode, thereby eliminating the need for SMS messages all of the time.

End-to-End Encryption

Making sure that your messaging services are end-to-end encrypted can also help when it comes to protecting yourself from OTP bots.

Using messaging services such as WhatsApp or Telegram can help to keep you safe. WhatsApp is automatically end-to-end encrypt
ed, whereas there is an option to select this with the padlock icon on any of your Telegram channels.

Final Thoughts

You can protect yourself from OTP bots in many ways that do not involve much skill, technique, expertise or knowledge.

Essentially, the main factors all come down to making sure that you are well-educated on OTP bots (which, by the time you have reached this part of the article, hopefully, you are!), and some cyber vigilance can go a long way.

Knowing how to identify these bots and protect yourself against them can help you and your business significantly in the long run.

Adding extra layers of multi-factor authentication to installing a CAPTCHA system or even pre-audit checks can help protect yourself from malicious hackers and OTP bots.