Mitigating Backdoor Attacks on Language Models through Model Merging

Kernekoncepter

The author proposes using model merging as an effective defense against backdoor attacks on language models, showcasing robustness and versatility in various contexts.

Resumé

The democratization of pre-trained language models has led to security risks like backdoor attacks. The paper suggests using model merging to mitigate these vulnerabilities effectively. By merging backdoored models with other models, the approach offers a cost-free solution to enhance security without retraining.

The study explores different models and datasets, demonstrating a 75% reduction in attack success rate compared to advanced defenses. Backdoor attacks manipulate model behavior with specific triggers, compromising integrity. Various defensive strategies exist but often require extra resources or specific knowledge.

Model merging techniques can counter backdoor attacks without external knowledge or retraining, consistently outperforming baselines. The method is adaptable across different settings and architectures, offering an efficient inference-stage defense strategy.

Experimental results show the effectiveness of model merging in reducing attack success rates across various datasets and poisoning rates. The approach remains robust even when merging models from different domains or trained for varying epochs.

Statistik

Compared to multiple advanced defensive approaches, the method offers an average of 75% reduction in the attack success rate.
The ASR reduction for BadNet ranges from 91.8% to 8.1% across different architectures.
ASR levels are comparable across different models, achieving over 90% reduction for certain attacks.
The ASR is consistently reduced by over 90% for BadNet and InsertSent attacks when merging clean datasets with a backdoored model.
TIES slightly outperforms Fisher and WAG in reducing ASR for backdoor attacks on SST-2.

Citater

"Model merging techniques can effectively mitigate backdoor attacks on PLMs."
"Our approach consistently achieves comparable performance across a range of models."

Vigtigste indsigter udtrukket fra

Here's a Free Lunch

by Ansh Arora,X... kl. arxiv.org 03-01-2024

https://arxiv.org/pdf/2402.19334.pdf

Dybere Forespørgsler

How can model merging be adapted to defend against other types of cyber threats beyond backdoor attacks?

Model merging can be adapted to defend against various cyber threats beyond backdoor attacks by leveraging the diversity and complementary strengths of different models. For instance, in the context of adversarial attacks, where subtle perturbations are made to inputs to deceive models, model merging can combine multiple models trained with different robustness techniques or architectures to enhance overall resilience. By aggregating predictions from diverse models, it becomes more challenging for attackers to craft effective adversarial examples that fool all merged models simultaneously.
Additionally, in the realm of data poisoning attacks aimed at manipulating training data to compromise model performance, model merging can integrate clean datasets or models trained on sanitized data sources with potentially compromised ones. This blending helps dilute the impact of poisoned samples and reduce vulnerabilities introduced by maliciously manipulated training instances.
Furthermore, for privacy-related threats such as membership inference attacks or attribute inference attacks targeting sensitive information within a dataset, model merging could involve combining specialized privacy-preserving techniques from individual models. By integrating differential privacy mechanisms or federated learning approaches into the merged model architecture, enhanced protection against privacy breaches can be achieved while maintaining high performance on standard tasks.
In essence, adapting model merging for defense against various cyber threats involves strategically combining diverse models with unique strengths and protective measures tailored to specific threat scenarios.

What are the potential limitations of relying solely on inference-stage defenses like model merging?

While inference-stage defenses like model merging offer valuable benefits in mitigating cyber threats without requiring access to training data or retraining affected models, they also come with certain limitations:

Dependency on Existing Models: Model merging relies heavily on the availability and quality of existing pre-trained models that align with the target task domain. In scenarios where suitable pre-trained models are limited or not readily accessible, implementing effective defense through model merging may prove challenging.

Limited Scope: Inference-stage defenses typically focus on detecting anomalies during prediction rather than addressing underlying vulnerabilities present in the training process itself. As a result, these defenses may not provide comprehensive protection against sophisticated attack strategies that exploit weaknesses inherent in deep learning architectures.

Overhead Costs: Merging multiple complex neural network architectures can lead to increased computational overhead and memory requirements during deployment. This additional complexity may hinder real-time application performance and scalability in resource-constrained environments.

Adversarial Transferability: Adversarial examples crafted specifically for one merged model might still generalize across ensemble members due to shared architectural features or vulnerabilities common among them. This transferability could undermine the effectiveness of inference-stage defenses based solely on ensemble methods like model merging.

Dynamic Threat Landscape: Cyber threats evolve rapidly over time as attackers develop new tactics and evasion strategies. Relying solely on static inference-stage defenses like model merging may struggle to adapt effectively to emerging threat vectors without continuous monitoring and updates.

How might advancements in model architecture impact the efficacy of defense strategies like model merging?

Advancements in modern deep learning architectures have significant implications for enhancing defense strategies like model merging:
1 .Specialized Architectures: Tailored neural network architectures designed specifically for security-critical tasks (e.g., robustness against adversarial attacks) can improve overall system resilience when integrated into a merged ensemble approach.
2 .Interpretability Features: Advanced interpretability features embedded within newer architectures enable better understanding of decision-making processes within each individual component before integration via mergers.
3 .Distributed Learning Techniques: Innovations such as decentralized learning frameworks (e.g., federated learning) allow collaborative training across multiple parties without sharing raw data directly—enabling secure collaboration between distinct entities contributing towards a merged defensive strategy.
4 .Privacy-Preserving Mechanisms: Enhanced privacy-preserving mechanisms incorporated into cutting-edge architectures facilitate secure aggregation protocols essential for preserving confidentiality while consolidating predictions from diverse sources during merger operations.
5 .Auto-Defense Capabilities: Self-defending networks equipped with adaptive response mechanisms triggered by detected anomalies contribute proactively towards fortifying collective intelligence gained through mergers—strengthening overall cybersecurity posture dynamically.
6 .Scalable Ensemble Integration: Scalable integration frameworks accommodating large-scale ensembles derived from advanced architectural designs ensure efficient fusion capabilities across heterogeneous components—optimizing resource utilization while maximizing defensive coverage provided by mergers.