What Are OTP Bots? How Cybercriminals Are Bypassing 2FA at Scale

OTP bots are automated tools that intercept one-time passwords (OTPs) by tricking victims into sharing their authentication codes in real time, bypassing two-factor authentication (2FA) and allowing attackers to complete account takeovers. Cisco Talos reports that nearly 50% of all incident response engagements in 2024 involved MFA bypass attempts, with OTP bots as the primary mechanism at scale.

The JokerOTP operation, dismantled by European authorities in early 2025, facilitated 28,000 attacks across 13 countries and generated an estimated $10 million in theft from banking customers, cryptocurrency users, and e-commerce account holders.

OTP Bot Definition

An OTP bot is an automated fraud tool that completes the final step of an account takeover: obtaining the one-time password that SMS-based 2FA systems send to a victim’s phone. The bot handles the interaction with the victim automatically, using pre-recorded voice calls or SMS messages to request the OTP under a plausible pretense and relay it to the attacker in real time.

OTP bots are classified as crimeware-as-a-service. They are sold on Dark Web markets and Telegram channels, requiring minimal technical skill from the buyer to operate.

How OTP Bots Work: The Step-by-Step Attack Flow

The attack requires the attacker to have the victim’s account credentials in advance, obtained through phishing, data breach databases, or credential stuffing. The OTP bot completes the attack by obtaining the 2FA code that the attacker cannot intercept directly.

• Credential acquisition

The attacker obtains the victim’s username and password through a previous breach or targeted phishing campaign.

• Attacker initiates login

The attacker enters the victim’s credentials on the target platform. The platform sends a one-time password to the victim’s phone.

• Bot contacts victim

The OTP bot immediately calls or texts the victim, impersonating the bank, platform, or a trusted entity. It presents a convincing scenario: unusual account activity detected, please verify your identity by entering the code we just sent.

• Victim provides OTP

Many victims comply, believing the contact is legitimate. The code they enter or speak is captured by the bot and relayed to the attacker’s interface in real time.

• Account compromise

The attacker enters the OTP before it expires, completing the 2FA verification and gaining full account access. The entire process typically takes under 30 seconds.

How OTP Bots Bypass Two-Factor Authentication?

SMS-based 2FA has a fundamental vulnerability: the OTP is delivered to the victim’s phone and requires the victim to enter it. If an attacker can persuade the victim to provide the code voluntarily, the technical protection of 2FA is completely nullified.

OTP bots exploit this vulnerability through social engineering rather than technical bypass. The shared secret between the platform and the user’s phone is never compromised. Instead, the user themselves is manipulated into sharing the code with the attacker.

Additional 2FA bypass methods that OTP bots support or work alongside include:

TOTP interception

For time-based OTP (TOTP) apps, real-time phishing pages can capture codes entered by victims and replay them before expiry.

SIM swapping

In some cases, attackers arrange for the victim’s phone number to be transferred to a SIM they control, directing OTPs to their own device without needing the victim to cooperate.

Industries Most Targeted by OTP Bot Attacks

Financial services organizations, particularly banks and credit unions with SMS-based 2FA on mobile banking, face the highest volume of OTP bot attacks. Fintech platforms and cryptocurrency exchanges are targeted because of the direct financial value of compromised accounts. E-commerce platforms and BNPL (Buy Now Pay Later) services are targeted for fraudulent purchases. Any platform with high-value accounts and SMS-based authentication is a potential target.

OTP Bots on the Dark Web: Marketplaces and Bot-as-a-Service

OTP bots are sold openly on Telegram channels and Dark Web forums. Pricing as of recent intelligence ranges from approximately $140 to $420 per week, payable in cryptocurrency. The bots are sold as managed services that include scripts for multiple impersonation scenarios, configurable voice settings, and real-time relay dashboards that display intercepted OTPs as they arrive.

JokerOTP is the most prominently documented example. Operating as a Telegram-based service, JokerOTP enabled buyers to conduct high-volume OTP interception campaigns with minimal technical knowledge. The operation ran for years before European authorities disrupted it in 2025.

How to Detect OTP Bot Attacks?

• Anomalous login attempts immediately followed by failed OTP verification from unusual geographic locations or device types
• Spike in OTP delivery requests for accounts with no corresponding user activity
• Customer reports of unexpected calls or texts claiming to be from the organization
• Device fingerprinting anomalies when login is completed from a device not associated with the account
• Behavioral analytics signals indicating the login pattern does not match the account holder’s established behavior

How to Prevent OTP Bot Attacks: Best Practices?

Passkeys and FIDO2 authentication

Passkey-based authentication eliminates the OTP entirely. Authentication is tied to a specific device and does not involve a code that can be intercepted or socially engineered. This is the most effective long-term mitigation for OTP bot attacks.

Hardware security keys

Physical keys implementing the FIDO2 protocol provide phishing-resistant MFA that OTP bots cannot intercept.

Risk-based authentication

Systems that analyze login risk signals, including device, location, behavior, and IP reputation, and step up authentication requirements for high-risk sessions reduce the attack surface for OTP bot attacks.

AI fraud detection

Real-time fraud detection models that identify OTP bot attack patterns, including the rapid sequence of credential entry, OTP request, and OTP submission, can block attacks that pass credential and OTP validation.

SMS pumping prevention

Rate limiting and carrier-level controls prevent attackers from generating large volumes of OTP SMS messages as part of reconnaissance or account enumeration.

How SOCRadar Threat Intelligence Protects Against OTP Bot Fraud?

SOCRadar’s Advanced Dark Web Monitoring tracks OTP bot services on Telegram and Dark Web markets. When new bots targeting specific platforms enter circulation, or when existing services add new impersonation scripts for a specific bank or service, this intelligence reaches security teams ahead of the attack wave. Credential intelligence monitoring identifies when account credentials from an organization’s users appear in breach databases, flagging accounts at elevated OTP bot attack risk.

Frequently Asked Questions

What is an OTP bot?

An OTP bot is an automated fraud tool that tricks victims into sharing their one-time passwords through fake calls or messages, allowing attackers to complete account takeovers that bypass 2FA.

Is 2FA secure against OTP bots?

SMS-based 2FA is vulnerable to OTP bots. Phishing-resistant MFA methods such as FIDO2 passkeys and hardware security keys are not vulnerable to OTP bot attacks.

How do I stop OTP bot attacks?

Moving from SMS-based 2FA to phishing-resistant authentication (FIDO2/passkeys) is the most effective mitigation. Risk-based authentication and real-time fraud detection also reduce exposure significantly.