Evaluating Large Language Models' Capability to Launch Fully Automated Spear Phishing Campaigns

In this paper, we evaluate the capability of large language models to conduct personalized phishing attacks and compare their performance with human experts and AI models from last year.We include four email groups with a combined total of 101 participants: A control group of arbitrary phishing emails, which received a click-through rate (recipient pressed a link in the email) of 12\%, emails generated by human experts (54\% click-through), fully AI-automated emails (54\% click-through), and AI emails utilizing a human-in-the-loop (56\% click-through). Thus, the AI-automated attacks performed on par with human experts and 350\% better than the control group. The results are a significant improvement from similar studies conducted last year. Our AI-automated emails were sent using a custom-built tool that automates the entire spear phishing process, including information gathering and creating personalized vulnerability profiles for each target. The AI-gathered information was accurate and useful in 88\% of cases and only produced inaccurate profiles for 4\% of the participants.We also use language models to detect the intention of emails. Claude 3.5 Sonnet scored well above 90\% with low false-positive rates and detected several seemingly benign emails that passed human detection. Lastly, we analyze the economics of phishing, highlighting how AI enables attackers to target more individuals at lower cost and increase profitability by up to 50 times for larger audiences.