Was Frost Bank hit by ransomware?

Frost Bank was listed by the Everest ransomware operation (United States), and stolen data was published on the group's leak site. Darkfield tracks this disclosure with the original leak post, screenshot and group context.

Who is the Everest ransomware group?

Everest is a ransomware operator tracked by Darkfield. See the full operator dossier for its known victims, sectors targeted, IOCs and leak-site infrastructure.

What data was leaked in the Frost Bank breach?

Everest published data attributed to Frost Bank. Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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Frost Bank

Claimed by Everest · listed 2 months ago

54d

Age

since listed · data leaked

Status timeline

ListedApr 20, 2026
Data leakeddate unknown

At a glance

Group: Everest
Status: Data leaked
Country: United States
Sector: Financial Services
Listed on leak site: Apr 20, 2026

About the victim

AI dossier — public-source company profile

Frost Bank is a Texas-based financial institution and wholly-owned subsidiary of Cullen/Frost Bankers, Inc., headquartered in San Antonio, Texas. Founded in 1868, it operates branches across major Texas metropolitan areas offering personal banking, commercial banking, wealth management, insurance, and investment services. It is one of the largest independent banks in Texas.

Industry: Commercial & Retail Banking
Address: 100 W. Houston Street, San Antonio, TX 78205, USA
Employees: 5000-10000
Founded: 1868

Attack summary

Severity: critical — Frost Bank is a large U.S. financial institution handling regulated financial and personal data for individuals and businesses. The disclosed status is 'data_published', confirming exfiltration and public release of data from a bank — a sector subject to strict financial and privacy regulations (GLBA, PCI-DSS), making this a critical-severity incident.

The Everest ransomware group claims to have attacked Frost Bank and has published data (disclosed status: data_published), indicating confirmed exfiltration of data from the institution. The specific nature and volume of exfiltrated data are not detailed in the truncated leak post.

critical

Data the group says was taken

AI dossier — extracted from the leak post

Financial records
Customer PII
Banking account data
Internal business documents

Original description

AI-summarised, not from the leak post

Frost Bank is a Texas-based financial institution and a subsidiary of Cullen/Frost Bankers, Inc. Founded in 1868 and headquartered in San Antonio, it operates across major Texas cities offering personal and commercial banking, wealth management, insurance, and investment services. As one of the largest independent banks in Texas, it serves individuals, businesses, and institutions within the United States financial services industry.

The leak post

captured from the group's site

© 2026, All rights reserved
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Sources

Leak posthttp://ransomocmou6mnbquqz44ewosbkjk3o5qjsl3orawojexfook2j7esad.onion/news/Frost_Bank/

Source

Indexed 2 months ago

This page surfaces a public ransomware disclosure indexed by Darkfield. Original posts come from the operator's own leak site; we cross-check against ransomware.live, RansomLook and RansomWatch where applicable. Share this URL freely.

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Disclosure context

About Everest

Everest is a financially-motivated ransomware group that emerged in September 2021, operating with a focus on profit-driven extortion campaigns against organizations primarily in the United States and Europe. The group's country of origin and specific affiliations remain undocumented in public threat intelligence reporting, though their operational patterns suggest they likely operate as an independent entity rather than a formal ransomware-as-a-service model. Limited public documentation exists regarding Everest's specific attack methodologies, initial access vectors, or technical capabilities, though their victim profile indicates they employ standard ransomware tactics targeting a diverse range of sectors including healthcare, technology, business services, and manufacturing organizations. Since their emergence, Everest has claimed responsibility for attacks against 339 victims across multiple countries, with the United States, United Kingdom, Italy, Germany, and Spain representing their primary geographic targets, though no specific high-profile incidents or major ransoms have been publicly documented by law enforcement or major security firms. As of current reporting, Everest appears to remain an active threat actor, though the limited public intelligence available suggests they operate as a lower-tier ransomware group compared to more prominent and well-documented criminal organizations. The group has been linked to 369 public disclosures across our corpus. First observed on a leak site on September 9, 2021; most recent post May 29, 2026. The operation is currently active.

Timeline of this disclosure

April 20, 2026Frost Bank listed by Evereston the group's public leak site

Other recent disclosures by Everest

Everest has been linked to 369 public victims on Darkfield. A sample of the most recent:

See the full Everest dossier →

Sector and geography

This disclosure adds to ransomware activity in the Financial Services sector, which has 516 disclosures indexed across all operators we track. Geographically, Frost Bank is reported in United States, a country with 2,714 ransomware disclosures in our corpus.

If your organisation is affected

A listing by Everest means Frost Bank appeared on a ransomware extortion site and data attributed to it has been published. If this is your organisation, or a supplier you depend on, the priority is to confirm the intrusion and contain it before the window to act closes.

Engage your incident-response team and preserve forensic evidence before remediating — do not wipe affected systems first.
Force a password reset and revoke active sessions for exposed accounts; rotate any credentials, API keys or certificates that may have been in the stolen data.
Assess regulatory notification duties (GDPR, NIS2, sector regulators) — many carry a 72-hour reporting clock from awareness.
Monitor for the data appearing on Everest's leak site and across paste and breach channels, and brief downstream partners who may be exposed through you.

How we know this. Darkfield monitors public ransomware leak sites continuously, archiving every new disclosure and the data later released against the victim. Each entry on this page is sourced from the operator's own publication and cross-checked against complementary OSINT feeds (RansomLook, ransomware.live, RansomWatch). We do not collect or host stolen data — only the metadata, timestamps and screenshots needed to make the public disclosure searchable and accountable. Records here are corrected when the original post is edited, retracted, or merged with another disclosure.