Anatomy of a Breach

Anatomy of a Breach: The Snowflake Campaign — Ticketmaster, Santander, and AT&T All Hit Through Stolen Credentials Without MFA

> series: anatomy_of_a_breach —— part: 185 —— platform: snowflake —— victims: ticketmaster_560M_santander_30M_att_110M —— root_cause: no_mfa<span class="cursor-blink">_</span>_

Hedgehog Security 31 May 2024 15 min read

Ticketmaster 560M. Santander 30M. AT&T 110M. All through Snowflake accounts without MFA.

In May-June 2024, a threat actor (tracked as UNC5537) systematically accessed Snowflake cloud data platform accounts belonging to approximately 165 organisations using credentials stolen through infostealer malware. The compromised accounts did not have multi-factor authentication enabled. The campaign yielded some of the largest data thefts of the year: Ticketmaster (approximately 560 million customer records), Santander (approximately 30 million), and — disclosed separately in July — AT&T (call and text metadata for approximately 110 million customers over a six-month period).

The credentials had been stolen by infostealer malware — Vidar, RedLine, and similar — installed on employees' personal devices or unmanaged computers. The stolen credentials were then sold on dark web marketplaces and used to log directly into Snowflake accounts that lacked MFA. Snowflake itself was not breached — the platform's own infrastructure was not compromised. The failures were entirely on the customer side: stolen credentials, no MFA, and no session monitoring. The campaign was the most consequential demonstration of the MFA imperative in the history of this series — affecting over 700 million people through a single, preventable authentication failure.


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The same lesson. Sixteen years. Still not learned.

MFA Would Have Prevented Everything
Every single compromise in the Snowflake campaign was through accounts without MFA. With MFA enabled, the stolen credentials would have been worthless. <a href="/cyber-essentials">Cyber Essentials Danzell</a> makes MFA an auto-fail criterion — the most important single control in cybersecurity, validated by sixteen years of this series.
Infostealer Malware on Personal Devices
The credentials were stolen by infostealer malware on employees' personal or unmanaged devices — highlighting the risk of BYOD and personal device usage for corporate access. <a href="/cyber-essentials">Cyber Essentials</a> addresses device management requirements. <a href="https://www.socinabox.co.uk">SOC in a Box</a> monitors for credential use from unmanaged devices.
Cloud Platform Security Is Your Responsibility
Snowflake was not breached — its customers' accounts were. Cloud platform security is a shared responsibility: the platform provider secures the infrastructure; the customer secures authentication and access. Our <a href="/penetration-testing/cloud-configuration-review">cloud configuration reviews</a> assess authentication controls on cloud platforms.
700 Million+ People Affected
Ticketmaster (560M), AT&T (110M), Santander (30M), and others — the combined impact exceeded 700 million individuals. The Snowflake campaign was the most impactful credential-based attack in history, surpassing even <a href="/blog/anatomy-of-a-breach-collection-1">Collection #1's</a> downstream impact. <a href="https://www.socinabox.co.uk/blog/what-is-the-dark-web-business-guide">Dark web monitoring</a> through <a href="https://www.socinabox.co.uk">SOC in a Box</a> detects stolen credentials before they are used.

MFA. The single control that keeps preventing the largest breaches in history.

The Snowflake campaign is the definitive case for MFA. Sixteen years of the Anatomy of a Breach series — 185 articles — and the single most impactful control remains multi-factor authentication. Every major breach in 2024 that involved credential compromise — Microsoft/Midnight Blizzard, Change Healthcare, and the Snowflake campaign — exploited accounts without MFA. Cyber Essentials Danzell makes MFA an auto-fail criterion because the evidence from 185 articles over sixteen years is irrefutable. Our penetration testing validates MFA enforcement. SOC in a Box monitors for credential compromise. And UK Cyber Defence provides incident response when authentication fails.


700 million people affected through Snowflake accounts without MFA. Is MFA enforced on every account in your organisation?

<a href="/cyber-essentials">Cyber Essentials Danzell</a> mandates MFA. <a href="/penetration-testing">Penetration testing</a> validates enforcement. <a href="https://www.socinabox.co.uk">SOC in a Box</a> monitors for credential theft.

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