Was Sermo hit by ransomware?

Sermo was listed by the Medusa 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 Medusa ransomware group?

Medusa 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 Sermo breach?

Medusa published data attributed to Sermo. Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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Sermo

Claimed by Medusa · listed 1 year ago

12m

Age

since listed · data leaked

Status timeline

ListedJul 6, 2025
Data leakeddate unknown

At a glance

Group: Medusa
Status: Data leaked
Country: United States
Sector: Healthcare
Listed on leak site: Jul 6, 2025

About the victim

AI dossier — public-source company profile

Sermo is an online social network platform exclusively for licensed physicians, offering peer-to-peer collaboration, medical crowdsourcing, clinical case discussions, and drug ratings. With over 1 million verified physicians globally, the platform enables healthcare professionals to share insights, earn money through medical surveys and research participation, and access educational content to improve patient care.

Industry: Healthcare Technology & Medical Social Networks
Address: 3 Times Square, 12th Floor, New York, NY 10036, United States
Employees: 450+

Attack summary

Severity: high — Sermo hosts sensitive professional and health-related data for over 1 million verified physicians. Confirmed data publication by a ransomware operator indicates exfiltration of potentially regulated healthcare professional information and medical knowledge base, creating significant exposure despite lack of stated ransom or specific proof inventory.

Medusa claims to have compromised Sermo and published exfiltrated data. The group post does not specify what data categories were taken or details of operational impact.

high

Data the group says was taken

AI dossier — extracted from the leak post

Physician profiles and credentials
User account information
Clinical discussion records
Drug rating database entries
Survey participation data

What the group claims

Sermo is an exclusive online community for licensed physicians, offering a platform for peer-to-peer collaboration, medical crowdsourcing, and real-time discussion of clinical cases. Sermo provides healthcare professionals with tools to connect globally, share insights, and improve patient care through collective knowledge. Sermo's corporate office is located at 3 Times Square, 12th Floor, New York, NY 10036, United States, and has 450+ employees.

Sources

Source

Indexed 1 year 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 Medusa

Medusa, also known as MedusaLocker, is a financially motivated ransomware group that emerged in November 2022 and has since compromised 568 known victims across multiple countries. The group's origin and specific affiliations remain unclear from publicly available intelligence, though their operational patterns suggest they function as an independent ransomware operation rather than a documented Ransomware-as-a-Service model. Medusa primarily targets organizations in the United States, United Kingdom, Canada, Italy, and Australia, with a focus on business services, healthcare, manufacturing, and technology sectors, employing typical ransomware tactics including data encryption and likely exfiltration for double extortion purposes, though specific technical methodologies and initial access vectors have not been extensively documented in public threat intelligence reports. While the group has maintained a relatively high victim count since its emergence, detailed information about specific notable campaigns, high-profile victims, or major ransom demands has not been widely reported by major cybersecurity firms or law enforcement agencies. As of current intelligence assessments, Medusa appears to remain active in the threat landscape, continuing to target organizations across their established geographic and sectoral preferences. The group has been linked to 635 public disclosures across our corpus. First observed on a leak site on November 15, 2022; most recent post May 5, 2026. The operation is currently active.

Also tracked as: MedusaLocker, MEDUSA LOCKER.

Timeline of this disclosure

July 6, 2025Sermo listed by Medusaon the group's public leak site

Other recent disclosures by Medusa

Medusa has been linked to 635 public victims on Darkfield. A sample of the most recent:

See the full Medusa dossier →

Sector and geography

This disclosure adds to ransomware activity in the Healthcare sector, which has 2,600 disclosures indexed across all operators we track. Geographically, Sermo is reported in United States, a country with 11,033 ransomware disclosures in our corpus.

If your organisation is affected

A listing by Medusa means Sermo 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 Medusa'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.