Topic starter
11/06/2026 12:03 am
TL;DR: OTP authentication remains more secure than static passwords, but it is increasingly bypassed through SIM swapping, SS7 interception, and real-time phishing, according to iProov. For high-assurance access, the control problem is no longer code generation; it is whether the verification method can survive modern interception and relay attacks.
Editorial analysis by NHI Mgmt Group, based on content published by iProov: “What Is OTP Authentication? How It Works, Risks & Alternatives (2026)”.
Key questions
Q: What breaks when OTP is used for high-assurance access?
A: OTP breaks when the organisation treats possession of a device or inbox as strong enough proof for sensitive actions.
Q: Why do OTP codes remain vulnerable even when they expire quickly?
A: Short expiry reduces replay risk, but it does not protect the delivery channel or the user session.
Q: How do security teams know when OTP is no longer appropriate?
A: OTP is no longer appropriate when a successful bypass would materially affect money movement, account recovery, or privileged access.
Practitioner guidance
- Reclassify high-risk journeys Move payments, account recovery, and privileged access out of OTP-only flows and into phishing-resistant authentication methods with stronger assurance properties.
- Retire SMS OTP from strong assurance paths Keep SMS-based codes only where the business accepts lower assurance, and remove them from workflows that would be materially harmed by interception or SIM swapping.
- Separate authenticator and session devices Avoid workflows where the same phone or browser session both generates the OTP and completes the transaction, because that collapses the intended factor separation.
Bottom line: OTP still adds protection compared with static passwords, but it no longer provides enough assurance for the highest-risk access journeys.
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This topic was modified 1 day ago by NHI Mgmt Group
12/06/2026 6:35 am
OTP is not collapsing because codes stopped expiring. It is collapsing because the delivery path, session timing, and user-device trust assumptions no longer hold. OTP was designed for a world where the receiver path was hard to interfere with and the code entered manually was the decisive control. That assumption fails when attackers can redirect numbers, intercept messages, or relay codes in real time. The implication is not that short-lived codes became obsolete overnight, but that assurance must now be measured against interception resilience, not token freshness.
A question worth separating out:
Q: What should organisations do when mobile numbers or inboxes are the second factor?
A: Organisations should assume the second factor is only as strong as the weakest delivery path. If the business still relies on phone numbers or email inboxes, it should add stronger verification for sensitive steps and reduce OTP exposure in recovery and transaction flows.
👉 Read our full editorial: OTP authentication is losing ground in high-assurance access
This post was modified 1 day ago by NHI Mgmt Group