arXiv:2606.08403cs.CRcs.AI2026-06中稿 · ICML

用浮点数伪装恶意指令,绕过文本检测但能被模型执行

Hiding in Plain Floats: Steganographic Carriers for Indirect Prompt and Content Injection

论文配图:Hiding in Plain Floats: Steganographic Carriers for Indirect Prompt and Content Injection
图 1 · 摘自论文原文
  • 将恶意内容编码为浮点数组,通过结构化输入传输
  • 在强防御下仍保持94.3%的攻击成功率,且可复现
  • 揭示了仅检视文本的系统存在隐蔽漏洞,适合安全研究者

现有文本中心的提示注入防御假设恶意信号在文本视图中可见。本文研究了一种可复现的间接提示/内容注入失败模式,该假设在此失效:一个以纯英文表达的载荷,当通过结构化浮点参数传输并在重建时被分割为碎片化遥测数据时,能绕过同一检测器。在三个不同提供商的商用LLM API上进行的14,400次真实模型攻击试验中,基于IFS的浮点数组载体在最强双层文本分类器防御(Prompt Guard 2 + TF-IDF集成)下仍保持94.3%的泄露攻击成功率(ASR)。相同载体模式在微调的roberta-base检测器上也复现成功。强调泄露ASR是因为下游系统可能对引用或重现的标记作出响应,即使模型拒绝执行;而强ASR是衡量结构合规攻击成功的更严格指标。2×2消融实验表明,数据层存储与重构层碎片化分别对抗不同文本视图,二者缺一不可。简单xxd检测与语义验证可阻断当前T3实例,因此本贡献并非不可检测的漏洞,而是为暴露于重构辅助通道的结构化输入管道中,仅依赖文本检查的系统设定了明确的失败边界。

原文摘要 · Abstract (English)

Text-centered prompt-injection defenses assume that the malicious signal is visible in one of the inspected text views. We study a reproducible LLM01-style indirect prompt/content-injection failure mode where that assumption breaks: a payload caught in plain English slips past the same detector when it is transported as structured float parameters and reconstructed only as fragmented telemetry. Across 14,400 attacked real-model trials on three commercial LLM APIs from different providers, the IFS-derived float-array carrier preserves 94.3% leakage ASR under the strongest dual-layer text-classifier defense evaluated in the main matrix: a Prompt Guard 2 + TF-IDF ensemble; the same carrier-level pattern also replicates with a fine-tuned roberta-base detector. We emphasize leakage ASR because downstream systems may act on quoted or reproduced markers even when the model refuses, but Strong ASR is the stricter metric for structurally compliant attack success. A 2 x 2 ablation shows that data-layer storage and reconstruction-layer fragmentation defeat different text views and that both are needed to evade both. A simple xxd detector and semantic validation block the current T3 instance, so the contribution is not an undetectable exploit but a measured failure boundary for text-only inspection in structured-input pipelines that expose reconstructed auxiliary channels to an LLM.

提示注入隐写术LLM安全

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