Summary
Between roughly April and June 2024, the threat group UNC5537 conducted mass data theft from about 165 Snowflake customer tenants. The attackers did not exploit any flaw in Snowflake itself; they logged in with valid usernames and passwords harvested by infostealer malware from employee and contractor machines and sold on criminal markets, some credentials years old. The targeted accounts had no MFA enabled and no network allow-listing, so stolen single-factor credentials granted direct access. Victims included Ticketmaster/Live Nation (about 560 million customers), Santander (about 30 million customers), and AT&T (call and text metadata for roughly 110 million customers, with AT&T reportedly paying about $370,000).
How to avoid it in your code
- Enforce MFA on every cloud data-platform account, especially admin and service accounts; never leave it optional.
- Restrict warehouse access with network policies/allowlists or private connectivity to known sources.
- Replace static user passwords with SSO and key-pair auth; rotate credentials immediately on exposure.
- Detect infostealer-harvested credentials and alert on logins from new locations, clients, or IPs.
- Apply least privilege to warehouse roles and alert on large or unusual data exports.
References
Related vulnerabilities
All OpSec →- CRITICALOPSEC-MIDNIGHT-BLIZZARD-2024
Disclosed January 19, 2024, the Russian SVR-linked actor Midnight Blizzard breached Microsoft's corporate tenant by password-spraying a legacy, non-production test account that had a weak password and no MFA, using residential proxies to evade detection. The actor then abused a malicious OAuth application, leveraging the test account's permissions to grant itself Exchange Online full_access_as_app rights and read corporate mailboxes. A small percentage of corporate email accounts were accessed, including senior leadership and staff in cybersecurity and legal functions, with some emails and attachments exfiltrated. A later update noted attempts to use exfiltrated secrets and source-code repository access.
- HIGHOPSEC-UBER-2022
In September 2022, an external contractor's Uber corporate credentials were compromised, likely purchased on the dark web after malware infected the contractor's personal device. The attacker launched an MFA fatigue push-bombing attack, flooding the contractor with 2FA approval requests, then posed as Uber IT over WhatsApp to convince them to approve one. Once inside, lateral movement reached hardcoded admin credentials in a PowerShell script on a network share, granting elevated access to G-Suite, Slack, vSphere, internal dashboards, and the HackerOne environment. Uber attributed the intrusion to an actor affiliated with Lapsus$ and stated no sensitive user data was exfiltrated.
- CRITICALOPSEC-23ANDME-2023
Disclosed October 6, 2023, 23andMe was hit by a credential-stuffing campaign running from about April 2023, in which the attacker reused username/password pairs leaked from unrelated prior breaches. Because many users reused passwords, roughly 14,000 accounts were directly compromised; 23andMe's own systems were not breached, but it failed to detect or throttle the automated logins and did not enforce MFA. From those accounts, the attacker abused the opt-in DNA Relatives and Family Tree features to scrape data on approximately 6.9 million additional individuals, including names and ancestry estimates, with curated ethnicity lists advertised for sale. Downstream fallout included an approximately $30 million class-action settlement, regulatory fines, and the company's eventual bankruptcy.
- CRITICALOPSEC-MGM-CAESARS-2023
In September 2023, the Scattered Spider group (an ALPHV/BlackCat ransomware affiliate) used vishing and help-desk social engineering to breach MGM Resorts and Caesars Entertainment. Attackers impersonated employees to IT help desks to obtain credentials and MFA resets, then moved laterally and deployed ransomware. Caesars had its loyalty-program database stolen, including driver's license and Social Security numbers, and reportedly paid roughly $15 million of a $30 million demand. MGM refused to pay, suffered an approximately $100 million hit to quarterly EBITDAR, had over 100 ESXi hypervisors encrypted, and exposed personal data of customers who transacted before March 2019.
- CRITICALOPSEC-LASTPASS-2022
LastPass suffered two linked breaches in 2022. In August, an attacker compromised a developer account and stole source code and technical documentation. Using that information, the attacker targeted a senior DevOps engineer, one of only four people with access to production backup decryption keys, by exploiting an unpatched vulnerability in Plex media software on the engineer's home computer to install a keylogger and capture the master password after MFA. Between August 12 and October 26, 2022, the attacker exfiltrated cloud backups including encrypted customer vaults (with unencrypted URLs), AWS S3 production backups, DevOps secrets, and MFA seed databases, putting customers with weak master passwords at offline brute-force risk.
- HIGHOPSEC-TWILIO-2022
On August 7, 2022, Twilio disclosed that attackers breached internal systems via an SMS phishing (smishing) campaign against employees. Staff received texts impersonating Twilio IT, claiming password expiry or schedule changes and using terms like Okta and SSO, directing them to fake login pages that harvested credentials. Several employees entered credentials, giving access to internal tools and data for 125 customers. Downstream, roughly 1,900 Signal users had phone numbers or SMS verification codes exposed and at least one account was re-registered to an attacker device, though message content and contacts remained protected. The broader 0ktapus campaign hit around 130 organizations.