From Trust to Compromise: Outcome-Verified LLM Phishing Simulation and Real-Time Defense
Paper · 2026 · Tulika Tewari, Nalin Arachchilage, Jagat Sesh Challa et al.
Summary
Prior LLM-based social-engineering simulators judge an attack successful only when the victim discloses PII inside the chat. Real compromises, however, often happen off-platform, for example when a persuaded user enters credentials on a malicious website. The authors address this gap with PhishSim. In this simulator, a Gemini-2.5-Flash attacker poses as a fake recruiter and talks with persona-conditioned victim agents. A victim's decision to follow a link is then carried out by a browser agent that submits credentials to a dummy portal, so compromise is verified by outcome.
The result is 1,833 multi-turn dialogues in both phishing and benign modes. On this data, the authors evaluate PhishGate, a real-time multi-agent risk scorer. It first filters messages for manipulation tactics, then estimates attack severity, and runs a RAG consistency check only when the evidence is ambiguous.
With each of the four LLM backends tested, PhishGate flags phishing across whole conversations better than a baseline that also runs in real time. It warns earlier, often before the URL appears, and depends less on link cues. The work offers an outcome-grounded testbed for conversational phishing defense, while showing that LLM detectors remain brittle.
Key points
- The PhishSim dataset has 1,833 dialogues, 919 of them phishing. Victims come from 192 personas built from gender, career level (early, mid or senior) and high or low levels of each Big Five trait.
- Attacker tactics follow Cialdini's principles. The most frequent in phishing chats are Urgency (31.0%), Authority (29.9%) and Likability/Rapport (29.4%).
- Compared with a RAG-only baseline, PhishGate's gating lowers the false-positive rate to 18.5%. It also cuts average latency from 2.08 s to 1.58 s per turn with Mistral Small 24B, avoiding about 32% overhead.
- Some generated dialogues contain unresolved placeholders, which could act as shortcut cues. A clean-subset ablation on 200 test dialogues still gives F1 0.81 and accuracy 0.80 on placeholder-free dialogues, versus 0.84 F1 overall.
- In the authors' evaluation, many LLM detectors had high false-positive rates and relied too heavily on URLs. Proprietary models such as Gemini performed comparatively well.
Institutions
Fields, topics and concepts
📚 Shelves 5The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksSocial Sciences · 1,772 worksInformation Systems · 1,437 worksSociology and Political Science · 577 works
🧭 Topics 1Research subjects and languages the work is about.Language models & pretraining · 3,320 works
Cite
Cite as Tulika Tewari, Nalin Arachchilage, Jagat Sesh Challa and Dhruv Kumar. 2026. From Trust to Compromise: Outcome-Verified LLM Phishing Simulation and Real-Time Defense. Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers).
@inproceedings{tewari2026trust,
title = {{From Trust to Compromise: Outcome-Verified LLM Phishing Simulation and Real-Time Defense}},
author = {Tulika Tewari, Nalin Arachchilage, Jagat Sesh Challa and Dhruv Kumar},
booktitle = {Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)},
year = {2026},
doi = {10.18653/v1/2026.acl-long.543},
url = {https://doi.org/10.18653/v1/2026.acl-long.543}
}References
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