Filter-then-Verify: A Multiphase GNN and ModernBERT Framework for Social Engineering Detection in Email Networks

Fuente: arXiv
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Auteurs principaux: Khadka, Barsat, Koirala, Prasant, Neupane, Kshitiz, Rahimi, Nick
Format: Preprint
Publié: 2026
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author Khadka, Barsat
Koirala, Prasant
Neupane, Kshitiz
Rahimi, Nick
author_facet Khadka, Barsat
Koirala, Prasant
Neupane, Kshitiz
Rahimi, Nick
contents Social engineering attacks exploit human trust rather than software vulnerabilities, making them difficult to detect using conventional filters. We propose a two-stage filter-then-verify framework combining inductive Graph Neural Networks (GNNs) for structural anomaly detection with a co-attention ModernBERT model for content verification. The GNN identifies anomalous sender-receiver patterns, while BERT analyzes message context to reduce false positives. Using the Enron dataset augmented with realistic synthetic campaigns, we show that the framework achieves 86% recall in structural filtering and over 92% precision after BERT refinement, effectively detecting both external attacks and insider threats. Our results demonstrate that combining structural and content analysis allows practical, scalable detection of multi-stage social engineering attacks in email networks.
format Preprint
id arxiv_https___arxiv_org_abs_2605_17201
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Filter-then-Verify: A Multiphase GNN and ModernBERT Framework for Social Engineering Detection in Email Networks
Khadka, Barsat
Koirala, Prasant
Neupane, Kshitiz
Rahimi, Nick
Cryptography and Security
Machine Learning
Social engineering attacks exploit human trust rather than software vulnerabilities, making them difficult to detect using conventional filters. We propose a two-stage filter-then-verify framework combining inductive Graph Neural Networks (GNNs) for structural anomaly detection with a co-attention ModernBERT model for content verification. The GNN identifies anomalous sender-receiver patterns, while BERT analyzes message context to reduce false positives. Using the Enron dataset augmented with realistic synthetic campaigns, we show that the framework achieves 86% recall in structural filtering and over 92% precision after BERT refinement, effectively detecting both external attacks and insider threats. Our results demonstrate that combining structural and content analysis allows practical, scalable detection of multi-stage social engineering attacks in email networks.
title Filter-then-Verify: A Multiphase GNN and ModernBERT Framework for Social Engineering Detection in Email Networks
topic Cryptography and Security
Machine Learning
url https://arxiv.org/abs/2605.17201