FARM: Few-shot Adaptive Malware Family Classification under Concept Drift
Numan Halit Guldemir, Oluwafemi Olukoya, Jesús Martínez-del-Rincón
TL;DR
FARM addresses concept drift in Windows PE malware classification by combining a triplet autoencoder for discriminative latent embeddings with DBSCAN-based drift detection and a two-stage adaptation strategy that blends few-shot prototype-based inference with optional full retraining. The triplet autoencoder optimizes $L_{\\text{triplet}}$ and reconstruction loss $L_{\\text{MSE}}$, projecting samples into a latent space where clusters are defined around centroids $\\mu_i$ with per-cluster thresholds $\\tau_i$. Drift is detected unsupervisedly via DBSCAN, enabling rapid identification of drifted samples, which are buffered and used to form new prototypes without immediate retraining. Experiments on the BenchMFC subset show covariate drift improvements of about $5.6\\%$ in $F1$ and unseen-family $F1$ rising from $0.85$ with few-shot adaptation to $0.94$ after retraining, demonstrating robustness and practical utility.
Abstract
Malware classification models often face performance degradation due to concept drift, arising from evolving threat landscapes and the emergence of novel malware families. This paper presents FARM (Few-shot Adaptive Recognition of Malware), a framework designed to detect and adapt to both covariate and label drift in Windows Portable Executable (PE) malware classification. FARM leverages a triplet autoencoder to project samples into a discriminative latent space, enabling unsupervised drift detection via DBSCAN clustering and dynamic thresholding. For rapid adaptation, it employs few-shot learning using prototype-based classification, requiring only a handful of labeled samples. FARM also supports full retraining when enough drifted samples accumulate, updating the latent space for long-term integration. Experiments on the BenchMFC dataset demonstrate that FARM improves classification performance under covariate drift by 5.6\%, and achieves an average F1 score of 0.85 on unseen malware families using only few-shot adaptation, which further increases to 0.94 after retraining. These results highlight FARM's robustness and adaptability in dynamic malware detection environments under limited supervision.
