Was horizonmedia.com hit by ransomware?

horizonmedia.com was listed by the chaos 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 chaos ransomware group?

chaos 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 horizonmedia.com breach?

chaos published data attributed to horizonmedia.com (~3.2 TB). Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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Horizon Media

listed as horizonmedia.com · Claimed by Chaos · listed 5 months ago

3.2 TB

Data size

Age

since listed · data leaked

Status timeline

ListedFeb 9, 2026
Data leakeddate unknown

At a glance

Group: Chaos
Status: Data leaked
Country: United States
Sector: Technology
Listed on leak site: Feb 9, 2026
Data size: 3.2 TB

About the victim

AI dossier — public-source company profile

Horizon Media is one of the largest independent media agencies in the United States, headquartered in New York City. The company specializes in media planning, buying, and data-driven marketing services across television, digital, radio, and out-of-home channels. It serves a broad portfolio of major national and global brand clients.

Industry: Media Buying & Advertising Agency
Employees: 1001-5000
Founded: 1989

Attack summary

Severity: high — The group claims exfiltration of 3.2 TB of sensitive corporate data from a large independent media agency with significant client and business information; while regulated PII at scale is not explicitly confirmed, the volume and threatened distribution to regulatory bodies indicates significant business and potentially client data exposure.

The Chaos ransomware group claims to have exfiltrated 3.2 TB of sensitive corporate data from Horizon Media and issued a 48-hour ultimatum to reach an agreement, threatening to publicly release the data and distribute it to global media outlets and regulatory bodies if terms are not met.

high

Data the group says was taken

AI dossier — extracted from the leak post

Corporate data (3.2 TB)
Sensitive business files

What the group claims

Official Announcement: Horizon Media Data Breach ULTIMATUM: Horizon Media has 48 hours to reach an agreement. If our terms are not met, a full leak consisting of 3.2 TB of sensitive corporate data will be made public and distributed to global media outlets and regulatory bodies. The leaked dataset…

Sources

Source

Indexed 5 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 chaos

Based on the limited publicly available information, Chaos is a recently emerged ransomware group that was first observed in March 2025, appearing to be financially motivated given their ransom demands and targeting patterns. The group's origin and specific affiliations remain unclear due to their recent emergence, though their operational model and whether they operate as Ransomware-as-a-Service or as an independent entity has not been definitively established by security researchers. Their attack methodology and specific technical capabilities are not yet well-documented in public threat intelligence reports, though their targeting suggests they employ common initial access vectors to compromise victims across multiple sectors. Chaos has claimed 41 victims primarily concentrated in the United States, Germany, Poland, Malaysia, and Sweden, with a particular focus on technology companies, financial services, business services, and manufacturing sectors, though the scope and impact of their most significant attacks have not been widely publicized. The group currently appears to be active based on recent victim claims, though comprehensive analysis from major security firms regarding their long-term operational capabilities and potential law enforcement actions remains limited due to their recent emergence in the threat landscape. The group has been linked to 69 public disclosures across our corpus. First observed on a leak site on March 31, 2025; most recent post July 14, 2026. The operation is currently active.

Timeline of this disclosure

February 9, 2026horizonmedia.com listed by chaoson the group's public leak site

Data size: 3.2 TB

Other recent disclosures by chaos

chaos has been linked to 69 public victims on Darkfield. A sample of the most recent:

See the full chaos dossier →

Sector and geography

This disclosure adds to ransomware activity in the Technology sector, which has 3,549 disclosures indexed across all operators we track. Geographically, horizonmedia.com is reported in United States, a country with 11,033 ransomware disclosures in our corpus.

If your organisation is affected

A listing by chaos means horizonmedia.com 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.
Report the incident to your national CERT, CISA (United States), as required for your jurisdiction.
Monitor for the data appearing on chaos'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.