Saturday, June 14, 2025
HomeSecurity NewsunCaptcha to Break reCaptcha System of Defense in 5.42 Seconds

unCaptcha to Break reCaptcha System of Defense in 5.42 Seconds

Published on

SIEM as a Service

Follow Us on Google News

Captcha challenge is the first line of defense to protect the website against attacks, it challenges to prove that you are the human user.

Google’s ReCaptcha was introduced in 2014 and it is used by the significant number of users and it relies on advanced risk analysis engine and it offers audio and image captcha, here security researchers took audio captcha to attack.

Security researchers from UM present unCaptcha, a low-resource, fully automated attack on Google’s 2017 reCaptcha audio captcha with a high success rate.

We have evaluated unCaptcha using over 450 reCaptcha challenges from live websites, and showed that it can solve them with 85.15% accuracy in 5.42 seconds, on average: less time than it takes to even play the audio challenge! Researchers said.
- Advertisement - Google News

To attack captcha one should have huge resources but anyway the success rate is very less.Here they provided a low resource attack with a high success rate.

Also Read Beware: Mass Ransomware Cyber Attack with “Bad Rabbit” Ransomware Hitting Many Government & Private organization

How unCaptcha works – Captcha

It is completely automated, they obtain audio samples and separated into segments for sound bites analysis and uploads to online speech recognization services like (IBM, Google Cloud, Google Speech Recognition, Sphinx, Wit-AI, Bing Speech Recognition).

captcha

And once the results are collected then it presents captcha solution.It is capable of locating “I’m not a robot” checkbox and clicks on it.Researchers also published the code of unCaptcha publically in Github.

Last February Researcher Discover “A logic vulnerability” dubbed ReBreakCaptcha that allows attackers to automate the process of bypassing reCAPTCHA fields. They published the source code in Github.

For mitigations they suggested in broadening the vocabulary of sound bites beyond just digits, adding background noise which makes the segmentation more difficult.

You can get full research paper titled unCaptcha: A Low-Resource Defeat of reCaptcha’s Audio Challenge available to download here.

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

Kali Linux 2025.2 Released: New Tools, Smartwatch and Car Hacking Added

Kali Linux, the preferred distribution for security professionals, has launched its second major release...

Arsen Launches AI-Powered Vishing Simulation to Help Organizations Combat Voice Phishing at Scale

Arsen, the cybersecurity startup known for defending organizations against social engineering threats, has announced...

NIST Releases New Guide – 19 Strategies for Building Zero Trust Architectures

The National Institute of Standards and Technology (NIST) has released groundbreaking guidance to help...

Spring Framework Flaw Enables Remote File Disclosure via “Content‑Disposition” Header

A medium-severity reflected file download (RFD) vulnerability (CVE-2025-41234) in VMware's Spring Framework has been...

Credential Abuse: 15-Min Attack Simulation

Credential Abuse Unmasked

Credential abuse is #1 attack vector in web and API breaches today (Verizon DBIR 2025). Join our live, 15-min attack simulation with Karthik Krishnamoorthy (CTO - Indusface) and Phani Deepak Akella (VP of Marketing - Indusface) to see hackers move from first probe to full account takeover.

Discussion points


Username & email enumeration – how a stray status-code reveals valid accounts.
Password spraying – low-and-slow guesses that evade basic lockouts.
Credential stuffing – lightning-fast reuse of breach combos at scale.
MFA / session-token bypass – sliding past second factors with stolen cookies.

More like this

Don’t Click “Unsubscribe” links blindly It May Leads to Loss of Credentials

Imagine your inbox is overflowing with promotional emails—some from familiar companies, others less so....

ConnectWise to Update Code Signing Certificates for ScreenConnect, Automate, and RMM

ConnectWise, a leading provider of remote management and cyber protection tools for managed service...

ESET Details on How to Manage Your Digital Footprint

ESET, a leading cybersecurity firm, has shed light on the intricate nature of digital...