Incident Score: Analysis & Impact (NEX1783601099)
The details regarding individual company incidents & reports gives you full view from every side.
Rankiteo Score Impact Analysis
Key Highlights From The Incident Analysis
- Timeline of Nextcloud's Breach and lateral movement inside company's environment.
- Overview of affected data sets, including SSNs and PHI, and why they materially increase incident severity.
- How Rankiteo’s incident engine converts technical details into a normalized incident score.
- How this cyber incident impacts Nextcloud Rankiteo cyber scoring and cyber rating.
- Rankiteo’s MITRE ATT&CK correlation analysis for this incident, with associated confidence level.
Full Incident Analysis Transcript
In this Rankiteo incident briefing, we review the Nextcloud breach identified under incident ID NEX1783601099.
The analysis begins with a detailed overview of Nextcloud's information like the linkedin page: https://www.linkedin.com/company/nextcloud-gmbh, the number of followers: 31200, the industry type: Software Development and the number of employees: 146 employees
After the initial compromise, the video explains how Rankiteo's incident engine converts technical details into a normalized incident score. The incident score before the incident was 753 and after the incident was 662 with a difference of -91 which is could be a good indicator of the severity and impact of the incident.
In the next step of the video, we will analyze in more details the incident and the impact it had on Nextcloud and their customers.
On 15 May 2026, Nextcloud disclosed Data Exposure issues under the banner "Nextcloud Exposes 367K Records in Unsecured ElasticSearch Cluster".
Security researchers from Cybernews uncovered an unprotected ElasticSearch cluster belonging to European cloud provider Nextcloud, exposing approximately 367,000 records (8GB) of sensitive internal and client data.
The disruption is felt across the environment, affecting ElasticSearch cluster, and exposing 367,000 records (8GB), with nearly 367,000 records at risk.
In response, moved swiftly to contain the threat with measures like Secured the database within two days of notification, and began remediation that includes Hosting infrastructure misconfiguration addressed, and stakeholders are being briefed through Notified relevant authorities; acknowledged need for forensic analysis.
The case underscores how Ongoing (forensic analysis required), with advisories going out to stakeholders covering Customer servers remained unaffected; breach unrelated to core cloud platform.
Finally, we try to match the incident with the MITRE ATT&CK framework to see if there is any correlation between the incident and the MITRE ATT&CK framework.
The MITRE ATT&CK framework is a knowledge base of techniques and sub-techniques that are used to describe the tactics and procedures of cyber adversaries. It is a powerful tool for understanding the threat landscape and for developing effective defense strategies.
MITRE ATT&CK® Correlation Analysis
Rankiteo's analysis has identified several MITRE ATT&CK tactics and techniques associated with this incident, each with varying levels of confidence based on available evidence. Under the Initial Access tactic, the analysis identified Exploit Public-Facing Application (T1190) with moderate confidence (60%), supported by evidence indicating unprotected ElasticSearch cluster belonging to European cloud provider and Exploitation of Remote Services (T1210) with moderate to high confidence (70%), supported by evidence indicating unsecured ElasticSearch cluster accessible to anyone with knowledge of the cluster’s location. Under the Credential Access tactic, the analysis identified Unsecured Credentials: Credentials In Files (T1552.001) with moderate confidence (50%), supported by evidence indicating scripts...some stored unencrypted leaving information accessible. Under the Collection tactic, the analysis identified Data from Local System (T1005) with high confidence (90%), supported by evidence indicating exposing approximately 367,000 records (8GB) of sensitive internal and client data and Data from Information Repositories (T1213) with moderate to high confidence (80%), supported by evidence indicating employee emails, client company details, contracts, and scripts...in a single index. Under the Exfiltration tactic, the analysis identified Exfiltration Over C2 Channel (T1041) with lower confidence (40%), supported by evidence indicating no evidence of unauthorized access, but malicious actors could have discovered the misconfiguration and Transfer Data to Cloud Account (T1537) with lower confidence (30%), supported by evidence indicating elasticSearch cluster exposed via hosting infrastructure misconfiguration. Under the Impact tactic, the analysis identified Endpoint Denial of Service: Application or System Exploitation (T1499.004) with lower confidence (30%), supported by evidence indicating potential unauthorized access to internal and client data and Data Manipulation: Stored Data Manipulation (T1565.001) with lower confidence (20%), supported by evidence indicating forensic analysis required to confirm whether data was accessed by third parties. Under the Defense Evasion tactic, the analysis identified Impair Defenses: Disable or Modify Tools (T1562.001) with moderate confidence (50%), supported by evidence indicating hosting infrastructure misconfiguration attributed as root cause. These correlations help security teams understand the attack chain and develop appropriate defensive measures based on the observed tactics and techniques.
Sources & References
- Nextcloud Rankiteo Cyber Incident Details: https://www.rankiteo.com/company/nextcloud-gmbh/incident/NEX1783601099
- Nextcloud CyberSecurity Rating page: https://www.rankiteo.com/company/nextcloud-gmbh
- Nextcloud Rankiteo Cyber Incident Blog Article: https://blog.rankiteo.com/nex1783601099-nextcloud-breach-may-2026/
- Nextcloud CyberSecurity Score History: https://www.rankiteo.com/company/nextcloud-gmbh/history
- Nextcloud CyberSecurity Incident Source: https://www.techradar.com/pro/security/nextcloud-leaks-367k-records-european-cloud-giant-exposes-staff-and-clients-in-major-breach
- Rankiteo A.I CyberSecurity Rating methodology: https://www.rankiteo.com/Images/rankiteo_algo.pdf
- Rankiteo TPRM Scoring methodology: https://static.rankiteo.com/model/rankiteo_tprm_methodology.pdf