🤖 AI Summary
Current red-teaming approaches for GUI agents often rely on white-box access or are easily mitigated by alignment mechanisms, limiting their ability to realistically assess agent robustness. This work proposes a semantic-level UI element injection attack that, under black-box conditions, overlays seemingly benign yet misleading visual elements onto interface screenshots via an Editor-Overlapper-Victim pipeline combined with an iterative search strategy. The method achieves the first effective visual perturbation against mainstream GUI agents, exposing a cross-model vulnerability in attention mechanisms and demonstrating that injected elements can persistently induce erroneous click behaviors. Experiments show the attack increases success rates by up to 4.4× compared to baselines; following a successful attack, target models click on malicious elements with a probability exceeding 15%, significantly higher than the 1% observed with random injections.
📝 Abstract
Existing red-teaming studies on GUI agents have important limitations. Adversarial perturbations typically require white-box access, which is unavailable for commercial systems, while prompt injection is increasingly mitigated by stronger safety alignment. To study robustness under a more practical threat model, we propose Semantic-level UI Element Injection, a red-teaming setting that overlays safety-aligned and harmless UI elements onto screenshots to misdirect the agent's visual grounding. Our method uses a modular Editor-Overlapper-Victim pipeline and an iterative search procedure that samples multiple candidate edits, keeps the best cumulative overlay, and adapts future prompt strategies based on previous failures. Across five victim models, our optimized attacks improve attack success rate by up to 4.4x over random injection on the strongest victims. Moreover, elements optimized on one source model transfer effectively to other target models, indicating model-agnostic vulnerabilities. After the first successful attack, the victim still clicks the attacker-controlled element in more than 15% of later independent trials, versus below 1% for random injection, showing that the injected element acts as a persistent attractor rather than simple visual clutter.