REEF and ANGLER red-team web agents by actually changing the state of the site
AspireAI community · arXiv
Web agents are deployed on real websites, where adversarially injected content can induce unauthorised actions - but existing evaluations use fixed attacks or a single attack type and judge them at the text level rather than through real state changes, which understates how vulnerable the agents are. REEF is a benchmark of red-teaming executable environments with faithful verification: it covers 9 verifier-grounded websites across travel, commerce, productivity, media and communication, pairing every authentic benign task with a malicious objective delivered through 5 attack types at both the user and the environment level. REEF's state-based verifiers feed ANGLER, an adaptive near-miss-guided lure evolution framework that uses prior rollout outcomes to guide LLM-based attack mutation and candidate selection instead of running a fixed attack set. Across 8 VLM-based web agents the authors report ANGLER reaches a 20.36% end-to-end attack success rate against 15.24% for the non-adaptive setting, and that the generated attacks cut benign task success rate from 61.9% to 44.4%. The limitation is that these are eight VLM-based agents on nine sites, not a live production exposure study.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.