NetEcho: From Real-World Streaming Side-Channels to Full LLM Conversation Recovery

Fuente: arXiv
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Auteurs principaux: Zhang, Zheng, Wu, Guanlong, Deng, Sen, Wang, Shuai, Zhang, Yinqian
Format: Preprint
Publié: 2025
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author Zhang, Zheng
Wu, Guanlong
Deng, Sen
Wang, Shuai
Zhang, Yinqian
author_facet Zhang, Zheng
Wu, Guanlong
Deng, Sen
Wang, Shuai
Zhang, Yinqian
contents In the rapidly expanding landscape of Large Language Model (LLM) applications, real-time output streaming has become the dominant interaction paradigm. While this enhances user experience, recent research reveals that it exposes a non-trivial attack surface through network side-channels. Adversaries can exploit patterns in encrypted traffic to infer sensitive information and reconstruct private conversations. In response, LLM providers and third-party services are deploying defenses such as traffic padding and obfuscation to mitigate these vulnerabilities. This paper starts by presenting a systematic analysis of contemporary side-channel defenses in mainstream LLM applications, with a focus on services from vendors like OpenAI and DeepSeek. We identify and examine seven representative deployment scenarios, each incorporating active/passive mitigation techniques. Despite these enhanced security measures, our investigation uncovers significant residual information that remains vulnerable to leakage within the network traffic. Building on this discovery, we introduce NetEcho, a novel, LLM-based framework that comprehensively unleashes the network side-channel risks of today's LLM applications. NetEcho is designed to recover entire conversations -- including both user prompts and LLM responses -- directly from encrypted network traffic. It features a deliberate design that ensures high-fidelity text recovery, transferability across different deployment scenarios, and moderate operational cost. In our evaluations on medical and legal applications built upon leading models like DeepSeek-v3 and GPT-4o, NetEcho can recover avg $\sim$70\% information of each conversation, demonstrating a critical limitation in current defense mechanisms. We conclude by discussing the implications of our findings and proposing future directions for augmenting network traffic security.
format Preprint
id arxiv_https___arxiv_org_abs_2510_25472
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle NetEcho: From Real-World Streaming Side-Channels to Full LLM Conversation Recovery
Zhang, Zheng
Wu, Guanlong
Deng, Sen
Wang, Shuai
Zhang, Yinqian
Cryptography and Security
In the rapidly expanding landscape of Large Language Model (LLM) applications, real-time output streaming has become the dominant interaction paradigm. While this enhances user experience, recent research reveals that it exposes a non-trivial attack surface through network side-channels. Adversaries can exploit patterns in encrypted traffic to infer sensitive information and reconstruct private conversations. In response, LLM providers and third-party services are deploying defenses such as traffic padding and obfuscation to mitigate these vulnerabilities. This paper starts by presenting a systematic analysis of contemporary side-channel defenses in mainstream LLM applications, with a focus on services from vendors like OpenAI and DeepSeek. We identify and examine seven representative deployment scenarios, each incorporating active/passive mitigation techniques. Despite these enhanced security measures, our investigation uncovers significant residual information that remains vulnerable to leakage within the network traffic. Building on this discovery, we introduce NetEcho, a novel, LLM-based framework that comprehensively unleashes the network side-channel risks of today's LLM applications. NetEcho is designed to recover entire conversations -- including both user prompts and LLM responses -- directly from encrypted network traffic. It features a deliberate design that ensures high-fidelity text recovery, transferability across different deployment scenarios, and moderate operational cost. In our evaluations on medical and legal applications built upon leading models like DeepSeek-v3 and GPT-4o, NetEcho can recover avg $\sim$70\% information of each conversation, demonstrating a critical limitation in current defense mechanisms. We conclude by discussing the implications of our findings and proposing future directions for augmenting network traffic security.
title NetEcho: From Real-World Streaming Side-Channels to Full LLM Conversation Recovery
topic Cryptography and Security
url https://arxiv.org/abs/2510.25472