Human-Interpretable Adversarial Prompt Attack on Large Language Models with Situational Context
Nilanjana Das, Edward Raff, Manas Gaur
TL;DR
The paper investigates safety vulnerabilities in LLMs to human-interpretable adversarial prompts by converting nonsensical suffixes into coherent prompts grounded in situational movie context, without requiring model weights. It introduces a gradient-free framework built on the PromptBench paradigm, composing prompts as $S = ext{MP} + ext{AdvIns} + ext{Sit}$ and expanding to $S'$ for stepwise reasoning and harm assessment, optionally using few-shot chain-of-thought. The situational data are drawn from IMDB crime movie overviews, with prompts anchored to specific films to enhance realism. Experimental results show that a single or very few demonstrations can induce harmful outputs across a range of open-source and proprietary LLMs, with transferability observed between models and varying sensitivity across architectures. The work highlights a security risk that is accessible to non-expert users and suggests the need for stronger safety mechanisms and evaluation frameworks to mitigate such gradient-free, context-driven prompt attacks.
Abstract
Previous research on testing the vulnerabilities in Large Language Models (LLMs) using adversarial attacks has primarily focused on nonsensical prompt injections, which are easily detected upon manual or automated review (e.g., via byte entropy). However, the exploration of innocuous human-understandable malicious prompts augmented with adversarial injections remains limited. In this research, we explore converting a nonsensical suffix attack into a sensible prompt via a situation-driven contextual re-writing. This allows us to show suffix conversion without any gradients, using only LLMs to perform the attacks, and thus better understand the scope of possible risks. We combine an independent, meaningful adversarial insertion and situations derived from movies to check if this can trick an LLM. The situations are extracted from the IMDB dataset, and prompts are defined following a few-shot chain-of-thought prompting. Our approach demonstrates that a successful situation-driven attack can be executed on both open-source and proprietary LLMs. We find that across many LLMs, as few as 1 attempt produces an attack and that these attacks transfer between LLMs.
