Faults That Fortify: CNN Adversarial Robustness via GPU Undervolting
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Faults That Fortify: CNN Adversarial Robustness via GPU Undervolting Behnam Omidi∗ ,Ahmad Tahmasivand∗ , Husam Alsyouri∗ , Saba Al-Sayouri† , Chongzhou Fang‡ Ihsen Alouani§ ,and Khaled N. Khasawneh∗ ∗ George Mason University, Fairfax, USA - Email: {bomidi, atahmasi, halsyour, kkhasawn}@gmu.edu † SecureMind Technologies Inc, Fairfax, USA - Email: saba@securemindtech.ai ‡ Rochester Institute of Technology, Rochester, USA - Email: cxfeec@rit.edu
arXiv:2608.20572v1 [cs.LG] 20 Aug 2026
§ Queen’s University, Belfast, UK - Email: i.alouani@qub.ac.uk
Abstract—Convolutional Neural Networks (CNNs) face a dual challenge: vulnerability to adversarial attacks and prohibitive training cost. Adversarial training is effective but expensive, a burden that grows as learning shifts to the energy-constrained edge. This paper addresses both through GPU undervolting during training. Reducing supply voltage introduces stochastic perturbations in arithmetic that act as implicit regularization, improving robustness while lowering power. We characterize undervolting-induced faults at the bit level, then train LeNet, VGG-6, and MobileNetV3 on MNIST and CIFAR-10 under two training regimes, standard and adversarial, each at nominal and undervolted voltage, and evaluate all models against adversarial attacks. In both regimes, the undervolted model consistently achieves higher adversarial accuracy than its nominal-voltage counterpart, showing that hardware-induced faults strengthen even adversarial training. Because dynamic power scales quadratically with supply voltage, these robustness gains arrive with substantial energy savings. GPU undervolting is therefore a readily deployable hardware-level defense requiring no algorithmic change, and opens a promising direction in which robustness and energy efficiency move together. Index Terms—Machine learning, Adversarial attacks, Fault injection, Undervolting, Power efficient training, AI Robustness.
I. I NTRODUCTION Convolutional Neural Networks (CNNs) have become a fundamental component of modern computer vision, enabling applications ranging from medical imaging to autonomous driving. However, training these models requires substantial computational resources, including high-performance GPUs and significant energy consumption [1]. These challenges are particularly pronounced in edge computing, where models are increasingly fine-tuned in addition to being deployed on resource-constrained platforms such as drones, wearable devices, and autonomous vehicles operating under stringent power budgets [2]. In such settings, the computational overhead of robustness-enhancing techniques is often prohibitive. Consequently, improving training efficiency while preserving both model accuracy and robustness has emerged as a critical research objective. Recent research focuses on the algorithmic level through quantization, pruning, and accelerator codesign [3], [4]. A complementary lever acts beneath it, where hardware modifications such as voltage scaling influence model performance
Fig. 1: Workflow overview
and learning dynamics [5]. Prior works have examined the security implications of this behavior, showing how undervolting can be exploited to induce faults in controlled ways [6], [7], while also demonstrating its potential as a defensive mechanism that injects benign noise to disrupt adversarial attacks [8], [9], [10]. These undervolting-induced faults result from diminished voltage margins that degrade transistor switching reliability, potentially causing timing violations, unstable storage behavior, and incorrect signal sampling during computation. Unlike memory-centric fault mechanisms, such as Rowhammer-induced DRAM disturbances or targeted weight corruption attacks [11], [12], [13], which involve persistent alterations to stored data and are addressed through corresponding mitigation approaches [14], [15], undervolting faults arise from transient disruptions in the underlying hardware execution process. It is also worth noting that these defensive mechanisms primarily operate during inference, where faults are introduced into an already trained model and are typically emulated through software-based injection [10], [8] rather than experimentally observed under undervolted hardware conditions. Consequently, the impact of transient faults during the training phase remains largely unexplored. In contrast, this work investigates transient faults induced exclusively through undervolting a physical GPU and examines whether such perturbations can be leveraged to beneficially influence training dynamics.
Impact on Power Consumption: Total GPU power is the sum of dynamic and static components,
Undervolting injects subtle stochasticity into the arithmetic of learning itself, which may push the network toward flatter representations rather than the sharp decision boundaries that gradient-based attacks exploit. Because dynamic power scales quadratically with supply voltage, the same knob also lowers energy consumption. The technique therefore carries a dual benefit, greener training and more resilient models, from one hardware setting requiring no algorithmic change. To investigate this, we run standard and adversarial training, each at nominal and undervolted GPU voltage, training LeNet [16], VGG-6 [17], and MobileNetV3 [18] on MNIST [16] and CIFAR-10 [19] and evaluating all models against PGD attacks [20] across a range of perturbation budgets (Figure 1). In both regimes, the undervolted variant is consistently more robust than its nominal-voltage counterpart while consuming less energy. These findings represent an encouraging first step rather than a complete defense. Beyond demonstrating that undervolting can improve robustness against adversarial attacks while simultaneously offering energy-efficiency benefits, our results suggest a promising new research direction at the intersection of hardware reliability, energy optimization, and AI robustness. Building on these encouraging results, future work in this area is encouraged to further explore bit-level fault behavior and extend evaluations to larger foundation and quantized models, where both robustness dynamics and energy savings may become even more pronounced. The contributions of this paper are summarized as follows. • We characterize the computational faults induced by undervolting on a real GPU, showing that they are stochastic yet controllable. • We propose training-time undervolting as a novel means of improving CNN robustness on GPUs, demonstrating that hardware-generated noise during training is a practical, easily deployable, and energy-efficient security mechanism. • We evaluate undervolting under both standard and adversarial training and show that it improves robustness in both regimes. • We quantify the resulting power reduction, showing that these robustness gains arrive alongside measurable energy savings and acceptable computational reliability.
2 Ptotal = Pdyn + Pstatic = αs CL Vdd fclk + Ileak Vdd ,
(1)
where αs is the switching activity factor, CL the effective load capacitance, fclk the clock frequency, and Ileak the leakage current. Because Pdyn scales quadratically with Vdd while Pstatic decreases linearly, lowering the voltage reduces both terms, at the cost of timing reliability. Voltage-Delay Relationship and Timing Faults: The propagation delay td of a CMOS logic gate depends strongly on the supply voltage, td ∝
Vdd , (Vdd − Vth )α
td ≤ Tclk =
1 , fclk
(2)
where Vth is the threshold voltage, α (typically between 1 and 2) the velocity saturation index, and Tclk the clock period. Correct operation requires the second condition to hold on every logic path. When undervolting pushes td beyond Tclk , timing violations occur and produce incorrect outputs or transient faults. The likelihood of such faults grows exponentially as the voltage margin shrinks, Pfault ≈ e−β(Vdd −Vmin ) ,
(3)
where Vmin is the minimum stable voltage and β a hardwaredependent sensitivity constant. As Vdd approaches Vmin , the system transitions sharply from reliable computation to frequent soft errors. In GPU workloads these faults appear mainly as small perturbations in floating-point arithmetic, ỹ = y + δ(Vdd ),
(4)
where y is the correct output, ỹ the computed result under undervolting, and δ(Vdd ) voltage-dependent noise whose variance grows as the voltage is lowered. Mild undervolting therefore introduces stochastic noise, whereas aggressive undervolting causes substantial numerical instability. Implications for Deep Learning: Such faults are not always harmful. Neural networks tolerate low-level noise because of their distributed representations, and the random errors induced by undervolting may act as a regularizer comparable to dropout or weight noise, potentially improving generalization and robustness. Excessive undervolting, in contrast, disrupts gradient-based optimization and degrades convergence and accuracy.
II. BACKGROUND AND R ELATED W ORK A. Undervolting-Induced Faults Undervolting, the reduction of a circuit’s supply voltage below its nominal level, is an effective way to improve energy efficiency in high-performance systems such as GPUs, since dynamic power scales approximately with the square of the supply voltage. The same reduction, however, slows transistor switching and degrades circuit timing, producing computational instability and transient faults. The quantitative relation between voltage, delay, and error probability therefore determines how undervolting affects GPU-based deep learning.
B. Randomization-based Defenses Convolutional Neural Networks (CNNs) remain vulnerable to adversarial perturbations, small crafted input changes that drastically alter predictions. Randomization-based defenses counter this threat by injecting stochasticity into inference or training so that the structured gradients attackers rely on become unreliable. Randomness has been applied at three levels: to inputs, through stochastic resizing, padding, and augmentation [21], [22]; to intermediate features, through
2
noise injection that turns a single network into an implicit ensemble of stochastic models [23]; and to parameters, through Monte Carlo dropout, Bayesian uncertainty modeling, and stochastic quantization or weight noise [24]. Randomized smoothing formalizes the idea by averaging predictions under Gaussian noise to obtain probabilistic robustness guarantees within a norm-ball [25], [26], with later variants improving certified robustness at comparable accuracy [27], [24]. The paradigm has known limits. Expectation-overtransformation attacks recover usable gradients by averaging over the randomization itself [28], and excessive noise degrades clean-input accuracy, so the degree of stochasticity requires calibration. Randomization nevertheless remains a flexible and inexpensive route to robustness, and hardwarelevel stochastic effects such as those induced by GPU undervolting extend it by supplying intrinsic randomization during training at no additional computational cost, while leaving inference deterministic.
training pipeline. Rather than suppressing these perturbations as errors, we treat them as intrinsic noise regularization, consistent with prior evidence that stochastic noise applied during training improves adversarial robustness [25]. Because per-operation perturbations concentrate in low-significance mantissa bits (Section V-A), they are small enough for optimization to converge to full clean accuracy, yet pervasive enough that their cumulative effect shapes the learned solution. At deployment, the model executes at nominal voltage; no faults occur at inference and the model’s outputs are fully deterministic. C. Training Procedure and Operating-Point Selection For each architecture–dataset pair, we sweep voltage– frequency operating points downward from nominal and select the lowest voltage at which training reliably completes, the point of maximum fault incidence short of instability. The GPU is held at this voltage for the entire training run, so perturbations act on every iteration from initialization to convergence. We evaluate the method under a 2×2 design: two training regimes, standard and adversarial, each executed at nominal and undervolted voltage with matched random seeds, weight initializations, and hyperparameters, so that within each regime the applied voltage is the only systematic difference between runs. Adversarial noise is deliberately crafted to maximize model error within a constrained threat model, whereas undervolting noise arises from hardware fluctuations outside the nominal voltage margin; because the two differ in both origin and statistical properties, we hypothesize that they act as complementary robustness mechanisms. In the adversarial regime, on-the-fly PGD example generation executes under the same voltage condition as the weight updates, since both are components of the training process. All trained models are evaluated identically at nominal voltage.
III. P ROPOSED M ETHODOLOGY We propose a training methodology that exploits hardwarelevel undervolting to inject beneficial stochastic noise into CNN training. This section defines the threat model, formalizes how undervolting-induced faults enter the learning process, and describes the training procedure and operatingpoint selection. A. Threat Model We consider the standard white-box evasion setting: the adversary has full knowledge of the trained model’s architecture and parameters and crafts Lp -bounded perturbations using first-order methods, instantiated in our evaluation as PGD over a range of budgets ϵ. The adversary attacks the deployed model, which executes at nominal voltage; the defender controls only the hardware configuration of the training process. We assume the defender’s GPU supports voltage adjustment through standard driver tooling and that training completes without fatal faults, a condition enforced by the operatingpoint selection in Section III-C. Fault-injection attacks on the model itself [11], [12], [13] are outside our scope.
IV. E XPERIMENTAL S ETUP All experiments used PyTorch on a dedicated server with an NVIDIA RTX 3090 GPU, which provides 10,496 CUDA cores and 24 GB of GDDR6X memory. Undervolting was applied through MSI Afterburner, which exposes voltage in 6 mV steps and frequency in 15 MHz steps, fine enough to explore the energy-accuracy trade-off across operating points systematically. We evaluated three architectures spanning a range of depths and computational budgets: the classical LeNet, a lightweight VGG-6, and MobileNetV3. Training used two benchmark image-classification datasets, MNIST and CIFAR-10. MNIST offers a clean, low-complexity setting for controlled observation of basic behavior, while CIFAR-10 demands deeper feature extraction and exercises undervolting under heavier computational load. To evaluate the robustness of the model, we employed the untargeted PGD attack implemented in the torchattacks version 3.5.1 library with α = 0.007 and 100 optimization steps, varying the perturbation budget ϵ until the model accuracy approached zero.
B. Undervolting as a Training-Time Noise Source As established in Section II, operating below nominal voltage perturbs individual arithmetic operations as ỹ = y + δ(Vdd ), where the variance of δ grows as voltage decreases. During training, every operation in the forward pass, backward pass, and weight update is subject to such perturbation. The parameter update at step t is therefore effectively wt+1 = wt − η (∇L(wt ) + δt ) ,
(5)
where η is the learning rate, L the training loss, and δt aggregates the voltage-induced perturbations accumulated through the computation of the gradient. Unlike software-based noise injection, which adds computation and targets a chosen site (inputs, activations, or weights), δt arises in every operation at zero computational cost and with no modification to the
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Flip 1 0 (bottom) Flip 0 1 (top, lighter)
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1 0 Sign Exponent (8 bits)
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(a) Bit flip distribution across bit position
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Fig. 2: Impact of undervolting on multiplication in GPU