MFA Safety: Why You Should Never Approve Unexpected Prompts (and Why App-Based MFA Is Safer Than SMS)
Multi-Factor Authentication (MFA) is one of the strongest protections available for your work accounts — but only when it’s used correctly.
Two of the most common causes of MFA-related security incidents are:
Approving an MFA prompt you didn’t expect
Relying on SMS text messages instead of app-based MFA
This post explains why both matter, what to watch for, and how to stay protected.
Why you should never approve an unexpected MFA prompt
When you receive an MFA prompt, it means:
Your password was already accepted
The system is asking for a second proof to complete the login
If you receive an MFA prompt you did not initiate, that is a red flag.
What an unexpected MFA prompt usually means
Someone else has your password
Your credentials were stolen via phishing or a fake login page
Your password was reused from another breached site
In other words:
Approving that prompt gives the attacker exactly what they need.
Common mistakes attackers rely on
Attackers often send repeated MFA prompts hoping that:
You’re distracted
You assume it’s a system glitch
You think “maybe I logged in earlier”
You approve it just to make it stop
This tactic is sometimes called MFA fatigue — and it works surprisingly often.
What to do if you get an unexpected MFA prompt
If you receive an MFA request you didn’t initiate:
❌ Do not approve it
❌ Do not ignore repeated prompts
✅ Deny the request (if possible)
✅ Report it to IT immediately
✅ Change your password if instructed
Quick reporting can prevent a full account compromise.
Why SMS (text message) MFA is less secure
Not all MFA methods provide the same level of protection.
While SMS-based MFA is better than no MFA at all, it has known weaknesses.
Risks with SMS MFA
Text messages can be intercepted
Phone numbers can be hijacked (SIM swapping)
Messages can be delayed or fail to arrive
SMS does not verify the device receiving the message
Attackers increasingly target SMS-based MFA because it’s easier to bypass.
Why app-based MFA is preferred
App-based MFA (such as authenticator apps) generates codes directly on your device.
Benefits of app-based MFA
Codes are generated locally, not sent over a network
Resistant to SIM-swap attacks
Works even without cellular service
Stronger protection against phishing attempts
Because of these advantages, app-based MFA is widely recommended and, in many environments, required.
How this protects you and the organization
Using MFA correctly:
Stops attackers even if they steal a password
Prevents account takeover
Protects email, files, and cloud services
Reduces the risk of widespread incidents
Many security standards and best-practice frameworks — including HIPAA, CMMC/NIST, PCI-DSS, and general cybersecurity guidance — either require or strongly recommend MFA, particularly app-based methods.
Common questions
What if I accidentally approved a prompt?
Report it immediately. The faster IT is notified, the better the chance of preventing further damage.
What if my phone isn’t available?
Backup MFA options can usually be configured. Contact IT before you’re locked out.
Is MFA annoying on purpose?
Yes — slightly. That friction is what stops attackers.
Our recommendation
We strongly recommend:
Never approving an MFA prompt you did not initiate
Using app-based MFA instead of SMS whenever possible
Reporting unexpected prompts immediately
MFA is one of the most effective security controls available — but only when users treat prompts carefully and use the strongest available method.
If you ever have questions about an MFA request, it’s always better to ask than to approve.