The Snowflake crisis has worsened seven weeks after the massive data breach at AT&T was disclosed.

• Nearly all AT&T wireless customers' data was connected to a breach, posing a growing problem for Snowflake.
• The most notable companies linked to the Snowflake attack were Advance Auto Parts, Lending Tree, Ticketmaster operator Live Nation Entertainment, and Santander Bank.
• In late May, Snowflake revealed a cyberattack and has since engaged CrowdStrike and Alphabet's Mandiant to conduct an investigation.

The cyberattack that compromised sensitive customer data at the software company's clients has caused problems for the company to worsen.

In a regulatory filing on Friday, AT&T revealed that hackers had gained access to customer data stored on a cloud platform for a six-month period in 2022. The data included phone numbers, call duration, and some cell site details, the telecom giant stated.

On Friday, Snowflake's shares dropped 1.8%, despite the Nasdaq rising 0.6%. An AT&T spokesperson informed CNBC that the cloud service was owned by Snowflake.

Since the Snowflake breach disclosure on May 30, 2024, the most severe incident has occurred, as stated in a blog post at the time. Snowflake collaborated with cybersecurity software vendor and Mandiant to investigate the potential unauthorized access to certain customer accounts on May 23, 2024.

Last month, Mandiant and Snowflake notified 165 "potentially exposed organizations" through their "Victim Notification Program" of a hack that Mandiant attributed to a financially motivated group known as UNC5537. The group, with members in North America and Turkey, used stolen login credentials that had been posted online after being stolen separately using malware.

The most notable companies linked to the Snowflake breach were Lending Tree, Ticketmaster operator, and Santander Bank, which announced in mid-May that they had discovered an unauthorized access to a Santander database hosted by a third-party provider prior to Snowflake's disclosure.

The company had 242 million customers for its U.S. wireless mobility services at the end of last year, with 128 million connected devices.

Nearly all of AT&T's wireless customers and customers of mobile virtual network operators using its wireless network had their data breached, the carrier said.

"Although the data does not contain customer names, it is possible to identify a specific telephone number using publicly available online tools," AT&T stated. Despite not obtaining access to call or text content, attackers were able to obtain customer information.

The Snowflake spokesperson declined to comment on the AT&T hack and instead referred to the company's previous statements regarding the attack.

Snowflake's systems were infected with malware as early as 2020, and some stolen credentials remained valid for years, according to Mandiant's blog post. In some cases, the credentials were taken on PCs used by contractors for Snowflake customers, which were also used for personal activities such as downloading pirated software.

UNC5537 was able to enter customers' Snowflake environments using their usernames and passwords because multi-factor authentication had not been enabled, according to Mandiant. The hackers then exported a significant amount of customer data. Since then, UNC5537 has started extorting victims and attempting to sell their data online, Mandiant stated.

On Friday, AT&T stated that it does not anticipate the attack will significantly affect its financials.

If Snowflake experiences an actual or perceived security breach or unauthorized parties obtain access to its customers' data, data, or platform, the company may face reputational harm and significant liabilities, as warned by investors.

This week, Snowflake enforced the use of multi-factor authentication through a blog post for administrators.

Sridhar Ramaswamy, the new CEO of Snowflake, faces a growing challenge as the company's stock declined 5% after management reduced the full-year adjusted operating income forecast, just days before a hacking disclosure.

In 2020, Snowflake, a software company founded in 2012, went public and raised over $3 billion in the largest IPO ever for a software company. Despite a significant first-day pop that increased its market cap to over $70 billion, Snowflake's stock has since decreased in value, closing at $134.73 on Friday for a valuation of approximately $45 billion.

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