TimeGuard: Channel-wise Pool Training for Backdoor Defense in Time Series Forecasting

Fuente: arXiv
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Autori principali: Nguyen, Quang Duc, Liang, Siyuan, Li, Yiming, Huo, Fushuo, Tao, Dacheng
Natura: Preprint
Pubblicazione: 2026
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author Nguyen, Quang Duc
Liang, Siyuan
Li, Yiming
Huo, Fushuo
Tao, Dacheng
author_facet Nguyen, Quang Duc
Liang, Siyuan
Li, Yiming
Huo, Fushuo
Tao, Dacheng
contents Time Series Forecasting (TSF) is highly vulnerable to backdoor attacks, yet effective defenses remain underexplored due to challenges arising from data entanglement and shifts in task formulation. To fill this gap, we conduct a systematic evaluation of thirteen representative backdoor defenses across the TSF life cycle and analyze their failure modes. Our results reveal two fundamental issues: (1) data entanglement induces channel-level signal dilution, rendering sample-filtering and trigger-synthesis defenses ineffective at localizing backdoors; and (2) task-formulation shift leads to training-loss degeneration, causing poisoned and clean windows to become indistinguishable at training stages. Based on these findings, we propose a training-time backdoor defense for TSF, termed TimeGuard. Our method adopts channel-wise pool training as the core paradigm and initializes a high-confidence pool using time-aware criteria to mitigate signal dilution. Moreover, we introduce distance-regularized loss selection to progressively expand the reliable pool during training and ease loss degeneration. Extensive experiments across multiple datasets, forecasting architectures, and TSF backdoor attacks demonstrate that TimeGuard substantially improves robustness, boosting $\mathrm{MAE}_\mathrm{P}$ by $1.96\times$ over the leading baseline, while preserving clean performance within 5% $\mathrm{MAE}_\mathrm{C}$.
format Preprint
id arxiv_https___arxiv_org_abs_2605_22365
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle TimeGuard: Channel-wise Pool Training for Backdoor Defense in Time Series Forecasting
Nguyen, Quang Duc
Liang, Siyuan
Li, Yiming
Huo, Fushuo
Tao, Dacheng
Cryptography and Security
Artificial Intelligence
Machine Learning
Time Series Forecasting (TSF) is highly vulnerable to backdoor attacks, yet effective defenses remain underexplored due to challenges arising from data entanglement and shifts in task formulation. To fill this gap, we conduct a systematic evaluation of thirteen representative backdoor defenses across the TSF life cycle and analyze their failure modes. Our results reveal two fundamental issues: (1) data entanglement induces channel-level signal dilution, rendering sample-filtering and trigger-synthesis defenses ineffective at localizing backdoors; and (2) task-formulation shift leads to training-loss degeneration, causing poisoned and clean windows to become indistinguishable at training stages. Based on these findings, we propose a training-time backdoor defense for TSF, termed TimeGuard. Our method adopts channel-wise pool training as the core paradigm and initializes a high-confidence pool using time-aware criteria to mitigate signal dilution. Moreover, we introduce distance-regularized loss selection to progressively expand the reliable pool during training and ease loss degeneration. Extensive experiments across multiple datasets, forecasting architectures, and TSF backdoor attacks demonstrate that TimeGuard substantially improves robustness, boosting $\mathrm{MAE}_\mathrm{P}$ by $1.96\times$ over the leading baseline, while preserving clean performance within 5% $\mathrm{MAE}_\mathrm{C}$.
title TimeGuard: Channel-wise Pool Training for Backdoor Defense in Time Series Forecasting
topic Cryptography and Security
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2605.22365