PuzzleMask: Abusing Plain Prose as a Covert AI Attack Vector
Check Point details PuzzleMask, a plain-prose technique that bypasses LLM gatekeeper policy checks, letting hidden payloads reach target models unreviewed.
Check Point Research describes PuzzleMask, a prompt-crafting technique that hides policy-violating payloads inside plain-English prose wrappers, bypassing quick LLM-based policy checks without emojis, Base64, or invisible formatting. The researchers tested 23 automated prompts against gatekeepers including GPT-4o-mini, GPT-OSS-Safeguard 20b, Claude 3 Haiku, and Llama Guard 3, and all were classified as safe despite policies that flagged the plain versions. When submitted to GPT-5 in thinking-high mode with a Python interpreter, the target model extracted and acted on the payload in over 90% of trials. The technique is not itself a jailbreak but can carry a jailbreak prompt as payload; mitigations include input paraphrasing, hardened gatekeeper policies, and output monitoring.
HarvestBench: Measuring Whether LLM Agents Will Pay to Avoid Killing Animals
HarvestBench, a reproducible farm-simulation benchmark, shows LLM agents pay fuel costs to avoid killing animals, with kill rates spanning 0.4% to 98.8% across nine models.
HarvestBench is a reinforcement-learning gridworld farm simulation where LLM agents choose between driving over animals at no cost or paying a posted fuel price to swerve during a cooperative corn harvest. Across nine models and 7,201 priced decisions, kill rates ranged from 0.4% to 98.8%, unordered by capability, with Terra and Sol the most merciful and GPT-4o-mini the most cruel. Morality briefings cut kill rates below 6% in five of six reasoning models, while removing them pushed rates above 84% in all six. The scorer counts events in the game log without an LLM grader, making results fully reproducible.