Horizon Media say January data breach compromised personal information

New York-based Horizon Media said that it suffered a significant cyber attack earlier this year that involved threat actors breaching its internal network and stealing confidential data.

 

Founded in 1989, Horizon Media is one of the world’s largest independent media agencies. The company helps marketers achieve business results through services such as media buying, consumer insights, digital marketing, and data analytics, managing more than $8.7 billion in billings and serving a wide range of clients and partners.

 

In a data security incident notice filed with the Office of Maine Attorney General, Horizon Media said that on January 9, it detected suspicious activity within its internal network, where threat actors gained access using social engineering techniques. The company immediately launched an investigation, with assistance from external cyber security experts, to determine the nature and scope of the incident.

 

“The investigation determined that an unauthorised actor gained access to a limited portion of our file shares on January 9, 2026, and copied certain files from our system,” reads the notice.

 

The compromised data included names and other personal identifiers including Social Security Numbers. The company, however, did not share the number of affected individuals.

 

“Horizon takes this incident and the security of information in our care seriously. We took immediate actions to ensure the security of our systems and investigate what occurred. We are assessing our policies, procedures, and infrastructure and are making improvements to our cybersecurity posture to reduce the chances of an event like this recurring. Additionally, we notified federal law enforcement and are cooperating with their investigation” the company added.

 

Horizon Media has advised all affected individuals to regularly monitor their credit reports, account and benefit statements and report any suspicious activity to law enforcement authorities, including the police and state attorney general. 

 

It has also offered two years of complimentary identity protection and credit monitoring services through Experian IdentityWorks to all affected individuals.

 

In February, the Chaos ransomware group claimed responsibility for the cyber attack on Horizon Media, listing it as a victim on its data leak site. The group

it had obtained 3.2TB of confidential data from the media agency and threatened to leak the entire database unless a ransom was paid.