Benjamin Franklin once said, “In this world, nothing is certain except death and taxes.” Now we can add one more thing to the list: user authentication. Multi-factor authentication (MFA) and the flood of push notifications are issues we encounter every day. This eventually leads to something called MFA fatigue. This year’s severe breaches happening through MFA fatigue include the Marks & Spencer breach. Therefore, vendors are already looking for alternatives. These include passkeys and behavioral MFA. Since we are talking about behavioral MFA, let us stick to it. Behavioral MFA, as is clear from the name, uses user behavior as a second factor for logging you in.
But how useful is it?
Behavioral MFA ensures logging in with much less friction. There is no hassle of remembering an ever-growing number of passwords or secrets. The only way to log in is just to be yourself. This provides a truly better user experience. It also continuously monitors users. The method also offers more security, as replicating behavior by a hundred percent is nearly impossible. These are the stated benefits. But how accurate are the claims?
First up, what exactly is a human behavior baseline? Human behavior can change due to physiological factors like stress and fatigue. The technology may get triggered if the user is signing in from a device. If the factors stated above are in play, we can very well see a lot of false positives, too.
Up next is a very critical issue in today’s times: data privacy. Behavioral MFA performs continuous verification. This data includes behavioral traits like movements and gestures, and mobile device usage. Storing this data is tricky, and there is a chance of falling afoul of data privacy norms like GDPR.
Scaling is also an issue. It has to establish a baseline for each person being onboarded. This can be a tricky option for smaller organizations. Baselining may take up to a few weeks to stabilize. Modern systems use AI baselines across large datasets to shorten onboarding. Instead of starting from zero, they compare new users to “similar profiles” (job role, location, device type). However, baselining is an issue in places witnessing a lot of churn or workplaces where employees are sharing devices. Also, using previous baselines does not reduce the issue of false positives.
The following table shows the difference between various access methods:
| Factor Type | Examples | Strengths | Weaknesses / Criticisms | Best Use Cases |
| Behavioral MFA | Typing cadence, mouse use, mobile swipes, gait analysis | – Continuous & invisible authentication- Reduces MFA fatigue- Stops account hijacking mid-session- Harder to “share” than OTPs | – False positives if behavior changes (stress, injury, new device)- Privacy concerns (constant monitoring)- Limited training data for new users- May struggle with accessibility/diverse user base | Enterprises with zero-trust models, high-value accounts, insider threat detection |
| SMS OTP (One-Time Passcode) | 6-digit code via text | – Simple, universal- No special hardware needed | – Vulnerable to SIM-swapping & interception- Fatigue if used too often- Weakest MFA factor by modern standards | Legacy systems, low-risk apps, consumer portals |
| TOTP Apps (Google Authenticator, Microsoft Authenticator) | Time-based codes on phone | – Stronger than SMS- Works offline- Widely adopted | – Users can still be phished- Inconvenient for frequent logins- Can be stolen if phone is compromised | General enterprise apps, SaaS platforms |
| Push Notifications | “Approve/Deny” on mobile app | – Easy, fast UX- Context-aware (shows login location/device) | – Vulnerable to MFA fatigue attacks- Attackers trick users into approving | Internal systems, VPN/SSO access |
| Hardware Tokens / Security Keys (YubiKey, FIDO2/WebAuth) | Physical key, NFC, USB | – Phishing-resistant- Very strong assurance- No shared secrets | – Extra cost per user- Harder for remote/contractors- Users may lose keys | High-security sectors (finance, defense, healthcare), admin accounts |
| Biometric MFA | Fingerprint, face recognition | – Convenient for users- Difficult to steal remotely- Seamless on mobile | – Privacy & storage concerns- Can’t be reset if compromised- Hardware dependency | End-user devices, consumer apps, mobile workforce |
Final Word:
Behavioral MFA can be more efficient when another technology is added as another authentication layer. However, CISOs still need to check three factors to evade vendor hype and the tool’s practical usefulness: False positive rate, resistance to attempts of mimicking user behavior, and its impact on user trust. Because, as QKS Group analyst Dhyey Sherasia puts it, “The MFA story is shifting from something you know or have to something you are. Behavioral MFA embodies this shift, but enterprises must decide if analyzing human behavior truly strengthens defenses or creates new cracks.”