Tuesday, April 1, 2025
HomeCyber Security NewsFacebook & Instagram Flaw Let Anyone Bypass Two-factor Authentication

Facebook & Instagram Flaw Let Anyone Bypass Two-factor Authentication

Published on

SIEM as a Service

Follow Us on Google News

The lack of rate-limiting in Instagram was discovered by Gtm Mänôz, a security researcher from Kathmandu, Nepal. 

This flaw could have allowed an attacker to bypass Facebook’s two-factor authentication by validating the targeted user’s already-validated Facebook mobile number using the Meta Accounts Center.

Two-Factor Authentication Bypass on Facebook 

The researcher looked at Instagram’s latest “Meta Accounts Center” layout and noticed that the “Personal Details” section allowed users to add their email and phone number to both their Instagram and linked Facebook accounts. This information can then be verified by entering the proper 6-digit code received by email or phone. 

https://miro.medium.com/max/697/1*xAUPLeIpfS3ogx3fZDqYNA.jpeg
Meta Accounts Center Layout

“At the time of reporting, the endpoint verifying the 6-digit code was vulnerable to lack of rate-limit protection allowing anyone to confirm unknown/known email and phone number both in Instagram and linked Facebook accounts”, the researcher explains.

The lack of a rate-limiting feature allowed an attacker to add an already-verified phone number to a target Facebook/Instagram account when Mänôz looked at Instagram’s new layout for “Meta Accounts.”

Facebook generates a one-time code after the user enters their mobile number to confirm their identification.

However, a threat actor may be able to generate unlimited bot traffic to launch a brute-force attack to validate a one-time Facebook PIN to link the accounts, thus bypassing Facebook’s 2FA protections, because of a rate-limiting flaw on Instagram’s endpoint.

According to the researcher, if the phone number was fully verified and 2FA was activated on Facebook, the victim’s account would no longer have 2FA enabled.

Additionally, if the phone number was only partially confirmed, i.e., used for 2FA, the 2FA will be revoked, and the phone number will be deleted from the victim’s account.

A screenshot of an email sent by Meta to a user that says: "We wanted to let you know that your phone number registered and verified by another person on Facebook."
Message from Meta informing that their two-factor protections have been disabled

“Basically the highest impact here was revoking anyone’s SMS-based 2FA just knowing the phone number,” according to Mänôz.

Since then, Meta has resolved the issue and as part of its bug bounty programme, it gave Mänôz $27,000. To avoid being exposed, users should upgrade their apps to the most recent version.

Network Security Checklist – Download Free E-Book

Gurubaran
Gurubaran
Gurubaran is a co-founder of Cyber Security News and GBHackers On Security. He has 10+ years of experience as a Security Consultant, Editor, and Analyst in cybersecurity, technology, and communications.

Latest articles

Sliver Framework Customized Enhances Evasion and Bypasses EDR Detection

The Sliver Command & Control (C2) framework, an open-source tool written in Go, has...

Ransomware Threatens 93% of Industries— Resilience Is Critical

Ransomware continues to be one of the most disruptive cyber threats, with recent data...

New Surge of IRS-Themed Attacks Targets Taxpayers’ Mobile Devices

As the U.S. tax filing deadline approaches, cybercriminals are intensifying their efforts to exploit...

KoiLoader Exploits PowerShell Scripts to Drop Malicious Payloads

Cybersecurity experts at eSentire's Threat Response Unit (TRU) uncovered a sophisticated malware campaign leveraging...

Supply Chain Attack Prevention

Free Webinar - Supply Chain Attack Prevention

Recent attacks like Polyfill[.]io show how compromised third-party components become backdoors for hackers. PCI DSS 4.0’s Requirement 6.4.3 mandates stricter browser script controls, while Requirement 12.8 focuses on securing third-party providers.

Join Vivekanand Gopalan (VP of Products – Indusface) and Phani Deepak Akella (VP of Marketing – Indusface) as they break down these compliance requirements and share strategies to protect your applications from supply chain attacks.

Discussion points

Meeting PCI DSS 4.0 mandates.
Blocking malicious components and unauthorized JavaScript execution.
PIdentifying attack surfaces from third-party dependencies.
Preventing man-in-the-browser attacks with proactive monitoring.

More like this

Sliver Framework Customized Enhances Evasion and Bypasses EDR Detection

The Sliver Command & Control (C2) framework, an open-source tool written in Go, has...

Ransomware Threatens 93% of Industries— Resilience Is Critical

Ransomware continues to be one of the most disruptive cyber threats, with recent data...

New Surge of IRS-Themed Attacks Targets Taxpayers’ Mobile Devices

As the U.S. tax filing deadline approaches, cybercriminals are intensifying their efforts to exploit...