Robot Visions: Breaking reCAPTCHA at Zero Cost and Zero Shot
Researchers defeat Google reCAPTCHA using free local models CLIP and OWLv2, achieving 92.6% per-session success at zero cost.
The paper taxonomizes Google reCAPTCHA challenges into Type A (independent tiles) and Type B (4x4 grid) and builds zero-shot, training-free solvers from open-source local models. CLIP solves 58% of Type A challenges and OWLv2 43.5% of Type B, while an end-to-end automated solver succeeds on 92.6% of 500 real-world sessions. The authors also show a non-technical adversary can solve challenges using natural-language instructions to a commodity AI assistant, collapsing the attacker skill floor and suggesting visual challenge CAPTCHAs have reached the end of their useful life.
- Zero-shot CLIP solver reaches 58% on Type A; OWLv2 43.5% on Type B grids
- End-to-end solver succeeds in 92.6% of 500 real reCAPTCHA sessions
- No training, API access, or per-attempt cost required, unlike prior cloud-VLM attacks
- Non-technical attackers can bypass challenges via commodity AI assistants
- Challenge-based visual CAPTCHAs may be obsolete as bot defenses
From the original article
1 min read at arxiv.orgGoogle reCAPTCHA is the most widely deployed visual CAPTCHA service, protecting hundreds of thousands of websites from automated bots. It serves as a critical line of defense against automated attacks, including credential stuffing, bulk account creation, and automated form abuse. It has proven largely effective since its introduction in 2007.
By Suphannee Sivakorn · arxiv.org
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