Hackers who stole terabytes of data from Ticketmaster and other customers of the cloud storage firm Snowflake claim they obtained access to some of the Snowflake accounts by first breaching a Belarusian-founded contractor that works with those customers.

About 165 customer accounts were potentially affected in the recent hacking campaign targeting Snowflake’s customers, but only a few of these have been identified so far. In addition to Ticketmaster, the banking firm Santander has also acknowledged that their data was stolen but declined to identify the account from which it was stolen. Wired, however, has independently confirmed that it was a Snowflake account; the stolen data included bank account details for 30 million customers, including 6 million account numbers and balances, 28 million credit card numbers, and human resources information about staff, according to a post published by the hackers. Lending Tree and Advance Auto Parts have also said they might be victims as well.

Snowflake has not revealed details about how the hackers accessed the accounts, saying only that the intruders did not directly breach Snowflake’s network. This week, Google-owned security firm Mandiant, one of the companies engaged by Snowflake to investigate the breaches, revealed in a blog post that in some cases the hackers first obtained access through third-party contractors, without identifying the contractors or stating how this access aided the hackers in breaching the Snowflake accounts.

But according to one of the hackers who spoke with WIRED through a text chat, one of those firms was EPAM Systems, a publicly traded software engineering and digital services firm, founded by Belarus-born Arkadiy Dobkin, with current revenue of around $4.8 billion. The hacker says his group, which calls themselves ShinyHunters, used data found on an EPAM employee system to gain access to some of the Snowflake accounts.

EPAM told WIRED that it does not believe that it played a role in the breaches and suggested the hacker had fabricated the tale. ShinyHunters has been around since 2020 and has been responsible for numerous breaches since then that involve stealing large troves of data and leaking or selling it online.

Snowflake is a large data storage and analysis firm that provides tools for companies to derive intelligence and insight from customer data. EPAM develops software and provides various managed services for customers worldwide, primarily in North America, Europe, Asia, and Australia, according to its web site, with about 60 percent of its revenue coming from customers in North America. Among the services EPAM provides customers is assistance with using and managing their Snowflake accounts to store and analyze their data. EPAM claims it has some 300 workers who are experienced in using Snowflake’s data analytics tools and services, and announced in 2022 that it had attained “Elite Tier Partner” status with Snowflake to leverage the latter’s analytics platform for its customers.

EPAM’s founder emigrated from Belarus to the US in the ’90s before founding his company in 1993 from his New Jersey apartment. Nearly two-thirds of EPAM’s 55,000 employees resided in Ukraine, Belarus, and Russia until Russia invaded Ukraine, at which point the company says it closed its Russia operations and moved some of its Ukrainian workers to locations outside of that country.

The hacker who spoke with WIRED says that a computer belonging to one of EPAM’s employees in Ukraine was infected with info-stealer malware through a spear-phishing attack. It’s unclear if someone from ShinyHunters conducted this initial breach or just purchased access to the infected system from someone else who hacked the worker and installed the infostealer. The hacker says that once on the EPAM worker’s system, they installed a remote-access Trojan, giving them complete access to everything on the worker’s computer.

Using this access, they say, they found unencrypted usernames and passwords that the worker used to access and manage EPAM customers’ Snowflake accounts, including an account for Ticketmaster. The hacker says the credentials were stored on the worker’s machine in a project management tool called Jira. The hackers were able to use those credentials, they say, to access the Snowflake accounts because the Snowflake accounts didn’t require multifactor authentication (MFA) to access them. (MFA requires that users type in a one-time temporary code in addition to a username and password, making accounts that use MFA more secure.)

While EPAM denies it was involved in the breach, hackers did steal data from Snowflake accounts including Ticketmaster's, and have extorted the owners of the data by demanding hundreds of thousands, and in some cases more than a million, dollars to destroy the data or risk having the hackers sell it elsewhere.

The hacker who spoke with WIRED didn’t identify all of the victims breached through EPAM but did indicate that Ticketmaster was one of them. Ticketmaster did not respond to a request for comment from WIRED. But Ticketmaster’s parent company, Live Nation, has acknowledged that data was stolen from its Snowflake account in May without revealing how much data was stolen or how the hackers accessed the Snowflake account. In a post offering the data for sale, however, the hackers indicated that they had taken data on 560 million Ticketmaster consumers.

The hacker claims that in some cases they were able to directly access the Snowflake account of EPAM customers using the plaintext usernames and passwords they found on the EPAM worker’s computer. But in cases where Snowflake credentials weren’t stored on the worker’s system, the hacker claims they sifted through stockpiles of old credentials stolen in previous breaches by hackers using infostealer malware and found additional usernames and passwords for Snowflake accounts, including ones harvested from the machine of the same EPAM worker in Ukraine.

Credentials harvested by infostealers are often posted online or made available for sale on hacker forums. If victims don’t change their login credentials after a breach, or don’t know their data has been stolen, those credentials can remain active and available for years. It’s especially problematic if those credentials are used across multiple accounts; hackers can identify the user through the email address they use as a login credential, and if that person reuses the same password, hackers can simply try those credentials in multiple places.

The hackers in this case say they were able to use credentials stolen by an infostealer in 2020 to access Snowflake accounts.

WIRED wasn’t able to independently confirm that the hackers were inside the EPAM worker’s machine or used EPAM to gain access to Ticketmaster’s data and other Snowflake accounts, but the hacker provided WIRED with a file that appears to be a list of EPAM worker credentials lifted from the company’s Active Directory database after they gained access to the worker’s computer.

Furthermore, in the blog post written by Mandiant, which was published after the hacker told WIRED about his group’s use of data harvested by infostealers, the security firm revealed that the hackers who breached Snowflake accounts used old data siphoned by infostealers to access some of the accounts. Mandiant said that about 80 percent of the victims it identified in the Snowflake campaign were compromised using credentials that had previously been stolen and exposed by infostealers.

And an independent security researcher who has been helping to negotiate the ransom transactions between the ShinyHunter hackers and victims of the Snowflake campaign pointed WIRED to an online repository of data harvested by an infostealer that includes data siphoned from the computer of the EPAM worker in Ukraine that the hacker says was used to gain access to the Snowflake accounts. This stolen data includes the worker’s browser history, which reveals the worker’s complete name. It also includes an internal EPAM URL pointing to Ticketmaster’s Snowflake account, as well as a plaintext version of the username and password that the EPAM worker used to access the Ticketmaster Snowflake account.

“This means that [an EPAM worker] who had access to that Snowflake [account] had password-stealing malware on their computer, and their password was stolen and sold on the dark web,” says the researcher, who asked to be identified only as Reddington, an identity they use online to communicate with cybercriminals. “This means that anyone that knew the correct URL to [Ticketmaster’s] Snowflake could have simply looked up the password, logged in, and stolen the data.”

An EPAM spokesperson did not seem to be aware when contacted by WIRED early this week that its company allegedly played a role in breaches of Snowflake accounts. “We do not comment on situations to which we are not a part,” she wrote in an email, suggesting the company did not believe it played any role in the campaign. When WIRED provided the spokeswoman with details about how the hackers say they obtained access to the system of an EPAM worker in Ukraine, she replied, “Hackers frequently spread false information to advance their agendas. We maintain a policy of not engaging with misinformation and consistently uphold robust security measures to protect our operations and customers. We are continuing our exhaustive investigation and, at this time, see no evidence to suggest that we have been affected or involved in this matter.”

WIRED followed up by providing the name of the Ukrainian worker whose machine the hackers allegedly compromised, as well as the username and password the worker used for accessing Ticketmaster’s Snowflake account, but the spokesperson did not respond to any additional questions.

It’s possible the ShinyHunter hackers did not directly hack the EPAM worker, and simply gained access to the Snowflake accounts using usernames and passwords they obtained from old repositories of credentials stolen by info stealers. But, as Reddington points out, this means that anyone else can sift through those repositories for these and other credentials stolen from EPAM accounts. Reddington says they found data online that was used by nine different infostealers to harvest data from the machines of EPAM workers. This raises potential concerns about the security of data belonging to other EPAM customers.

EPAM has customers across various critical industries, including banks and other financial services, health care, broadcast networks, pharmaceutical, energy and other utilities, insurance, and software and hi-tech—the latter customers include Microsoft, Google, Adobe, and Amazon Web Services. It’s not clear, however, if any of these companies have Snowflake accounts to which EPAM workers have access. WIRED also wasn’t able to confirm whether Ticketmaster, Santander, Lending Tree, or Advance AutoParts are EPAM customers.

The Snowflake campaign also highlights the growing security risks from third-party companies in general and from infostealers. In its blog post this week, Mandiant suggested that multiple contractors were breached to gain access to Snowflake accounts, noting that contractors—often known as business process outsourcing (BPO) companies—are a potential gold mine for hackers, because compromising the machine of a contractor that has access to the accounts of multiple customers can give them direct access to many customer accounts.

“Contractors that customers engage to assist with their use of Snowflake may utilize personal and/or non-monitored laptops that exacerbate this initial entry vector,” wrote Mandiant in its blog post. “These devices, often used to access the systems of multiple organizations, present a significant risk. If compromised by infostealer malware, a single contractor's laptop can facilitate threat actor access across multiple organizations, often with IT and administrator-level privileges.”

The company also highlighted the growing risk from infostealers, noting that the majority of the credentials the hackers used in the Snowflake campaign came from repositories of data previously stolen by various infostealer campaigns, some of which dated as far back as 2020. “Mandiant identified hundreds of customer Snowflake credentials exposed via infostealers since 2020,” the company noted.

This, accompanied by the fact that the targeted Snowflake accounts didn’t use MFA to further protect them, made the breaches in this campaign possible, Mandiant notes.

Snowflake’s CISO, Brad Jones, acknowledged last week that the lack of multifactor authentication enabled the breaches. In a phone call this week, Jones told WIRED that Snowflake is working on giving its customers the ability to mandate that users of their accounts employ multifactor authentication going forward, “and then we’ll be looking in the future to [make the] default MFA,” he says.

Update 6/17/2024, 5:45 pm EDT: The article was updated to clarify the details that Santander has publicly revealed about the hack.