Characterizing the Networks Sending Enterprise Phishing Emails

Fuente: arXiv
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Hauptverfasser: Luo, Elisa, Young, Liane, Ho, Grant, Afifi, M. H., Schweighauser, Marco, Katz-Bassett, Ethan, Cidon, Asaf
Format: Preprint
Veröffentlicht: 2024
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author Luo, Elisa
Young, Liane
Ho, Grant
Afifi, M. H.
Schweighauser, Marco
Katz-Bassett, Ethan
Cidon, Asaf
author_facet Luo, Elisa
Young, Liane
Ho, Grant
Afifi, M. H.
Schweighauser, Marco
Katz-Bassett, Ethan
Cidon, Asaf
contents Phishing attacks on enterprise employees present one of the most costly and potent threats to organizations. We explore an understudied facet of enterprise phishing attacks: the email relay infrastructure behind successfully delivered phishing emails. We draw on a dataset spanning one year across thousands of enterprises, billions of emails, and over 800,000 delivered phishing attacks. Our work sheds light on the network origins of phishing emails received by real-world enterprises, differences in email traffic we observe from networks sending phishing emails, and how these characteristics change over time. Surprisingly, we find that over one-third of the phishing email in our dataset originates from highly reputable networks, including Amazon and Microsoft. Their total volume of phishing email is consistently high across multiple months in our dataset, even though the overwhelming majority of email sent by these networks is benign. In contrast, we observe that a large portion of phishing emails originate from networks where the vast majority of emails they send are phishing, but their email traffic is not consistent over time. Taken together, our results explain why no singular defense strategy, such as static blocklists (which are commonly used in email security filters deployed by organizations in our dataset), is effective at blocking enterprise phishing. Based on our offline analysis, we partnered with a large email security company to deploy a classifier that uses dynamically updated network-based features. In a production environment over a period of 4.5 months, our new detector was able to identify 3-5% more enterprise email attacks that were previously undetected by the company's existing classifiers.
format Preprint
id arxiv_https___arxiv_org_abs_2412_12403
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Characterizing the Networks Sending Enterprise Phishing Emails
Luo, Elisa
Young, Liane
Ho, Grant
Afifi, M. H.
Schweighauser, Marco
Katz-Bassett, Ethan
Cidon, Asaf
Cryptography and Security
Phishing attacks on enterprise employees present one of the most costly and potent threats to organizations. We explore an understudied facet of enterprise phishing attacks: the email relay infrastructure behind successfully delivered phishing emails. We draw on a dataset spanning one year across thousands of enterprises, billions of emails, and over 800,000 delivered phishing attacks. Our work sheds light on the network origins of phishing emails received by real-world enterprises, differences in email traffic we observe from networks sending phishing emails, and how these characteristics change over time. Surprisingly, we find that over one-third of the phishing email in our dataset originates from highly reputable networks, including Amazon and Microsoft. Their total volume of phishing email is consistently high across multiple months in our dataset, even though the overwhelming majority of email sent by these networks is benign. In contrast, we observe that a large portion of phishing emails originate from networks where the vast majority of emails they send are phishing, but their email traffic is not consistent over time. Taken together, our results explain why no singular defense strategy, such as static blocklists (which are commonly used in email security filters deployed by organizations in our dataset), is effective at blocking enterprise phishing. Based on our offline analysis, we partnered with a large email security company to deploy a classifier that uses dynamically updated network-based features. In a production environment over a period of 4.5 months, our new detector was able to identify 3-5% more enterprise email attacks that were previously undetected by the company's existing classifiers.
title Characterizing the Networks Sending Enterprise Phishing Emails
topic Cryptography and Security
url https://arxiv.org/abs/2412.12403