TrapFlow: Controllable Website Fingerprinting Defense via Dynamic Backdoor Learning

Fuente: arXiv
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Main Authors: Liang, Siyuan, Gong, Jiajun, Fang, Tianmeng, Liu, Aishan, Wang, Tao, Cao, Xiaochun, Tao, Dacheng, Chang, Ee-Chien
Format: Preprint
Published: 2024
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_version_ 1866914339250765824
author Liang, Siyuan
Gong, Jiajun
Fang, Tianmeng
Liu, Aishan
Wang, Tao
Cao, Xiaochun
Tao, Dacheng
Chang, Ee-Chien
author_facet Liang, Siyuan
Gong, Jiajun
Fang, Tianmeng
Liu, Aishan
Wang, Tao
Cao, Xiaochun
Tao, Dacheng
Chang, Ee-Chien
contents Website fingerprinting (WF) attacks, which covertly monitor user communications to identify the web pages they visit, pose a serious threat to user privacy. Existing WF defenses attempt to reduce attack accuracy by disrupting traffic patterns, but attackers can retrain their models to adapt, making these defenses ineffective. Meanwhile, their high overhead limits deployability. To overcome these limitations, we introduce a novel controllable website fingerprinting defense called TrapFlow based on backdoor learning. TrapFlow exploits the tendency of neural networks to memorize subtle patterns by injecting crafted trigger sequences into targeted website traffic, causing the attacker model to build incorrect associations during training. If the attacker attempts to adapt by training on such noisy data, TrapFlow ensures that the model internalizes the trigger as a dominant feature, leading to widespread misclassification across unrelated websites. Conversely, if the attacker ignores these patterns and trains only on clean data, the trigger behaves as an adversarial patch at inference time, causing model misclassification. To achieve this dual effect, we optimize the trigger using a Fast Levenshtein like distance to maximize both its learnability and its distinctiveness from normal traffic. Experiments show that TrapFlow significantly reduces the accuracy of the RF attack from 99 percent to 6 percent with 74 percent data overhead. This compares favorably against two state of the art defenses: FRONT reduces accuracy by only 2 percent at a similar overhead, while Palette achieves 32 percent accuracy but with 48 percent more overhead. We further validate the practicality of our method in a real Tor network environment.
format Preprint
id arxiv_https___arxiv_org_abs_2412_11471
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle TrapFlow: Controllable Website Fingerprinting Defense via Dynamic Backdoor Learning
Liang, Siyuan
Gong, Jiajun
Fang, Tianmeng
Liu, Aishan
Wang, Tao
Cao, Xiaochun
Tao, Dacheng
Chang, Ee-Chien
Cryptography and Security
Artificial Intelligence
68M10
C.2.0
Website fingerprinting (WF) attacks, which covertly monitor user communications to identify the web pages they visit, pose a serious threat to user privacy. Existing WF defenses attempt to reduce attack accuracy by disrupting traffic patterns, but attackers can retrain their models to adapt, making these defenses ineffective. Meanwhile, their high overhead limits deployability. To overcome these limitations, we introduce a novel controllable website fingerprinting defense called TrapFlow based on backdoor learning. TrapFlow exploits the tendency of neural networks to memorize subtle patterns by injecting crafted trigger sequences into targeted website traffic, causing the attacker model to build incorrect associations during training. If the attacker attempts to adapt by training on such noisy data, TrapFlow ensures that the model internalizes the trigger as a dominant feature, leading to widespread misclassification across unrelated websites. Conversely, if the attacker ignores these patterns and trains only on clean data, the trigger behaves as an adversarial patch at inference time, causing model misclassification. To achieve this dual effect, we optimize the trigger using a Fast Levenshtein like distance to maximize both its learnability and its distinctiveness from normal traffic. Experiments show that TrapFlow significantly reduces the accuracy of the RF attack from 99 percent to 6 percent with 74 percent data overhead. This compares favorably against two state of the art defenses: FRONT reduces accuracy by only 2 percent at a similar overhead, while Palette achieves 32 percent accuracy but with 48 percent more overhead. We further validate the practicality of our method in a real Tor network environment.
title TrapFlow: Controllable Website Fingerprinting Defense via Dynamic Backdoor Learning
topic Cryptography and Security
Artificial Intelligence
68M10
C.2.0
url https://arxiv.org/abs/2412.11471