Incident Score: Analysis & Impact (CLO1790310238)
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Rankiteo Score Impact Analysis
Key Highlights From The Incident Analysis
- Timeline of Cloudflare's Vulnerability 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 Cloudflare 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 Cloudflare breach identified under incident ID CLO1790310238.
The analysis begins with a detailed overview of Cloudflare's information like the linkedin page: https://www.linkedin.com/company/cloudflare, the number of followers: 1188930, the industry type: Computer and Network Security and the number of employees: 7336 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 488 and after the incident was 486 with a difference of -2 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 Cloudflare and their customers.
On 04 September 2026, Cloudflare disclosed Data Exposure issues under the banner "Cloudflare Patches Cross-Tenant Data Exposure Flaw in Containers Platform".
Cloudflare addressed a critical cross-tenant data exposure vulnerability in its Containers platform, which could have allowed one customer’s workload to access residual disk data from another tenant on the same physical host.
The disruption is felt across the environment, affecting Cloudflare Containers, Cloudflare Sandboxes, and exposing Residual disk data fragments (filesystem metadata, database pages, SQLite databases), with nearly 2,700 distinct foreign inodes (residual data fragments) records at risk.
In response, teams activated the incident response plan, moved swiftly to contain the threat with measures like Disabling `skip_block_zeroing` in dm-thin provisioning, Retiring existing container disks and Draining hosts and restarting VMs, and began remediation that includes Enforcing block clearing on new allocations and Developing detection signatures for unusual I/O patterns, while recovery efforts such as No customer action required; recommended rotating secrets handled by affected workloads continue.
The case underscores how Completed (no evidence of malicious exploitation), teams are taking away lessons such as Importance of zeroing recycled storage blocks in multi-tenant environments; need for robust detection of unusual I/O patterns in cloud infrastructure, and recommending next steps like Rotate secrets handled by affected workloads based on risk policies, Audit storage layer configurations for similar misconfigurations and Implement automated detection for cross-tenant data exposure risks, with advisories going out to stakeholders covering No customer action required; recommended rotating secrets if applicable.
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 critical cross-tenant data exposure vulnerability in its Containers platform and Exploitation of Remote Services (T1210) with moderate to high confidence (70%), supported by evidence indicating exploitation required a Workers Paid account in shared cloud infrastructure. Under the Privilege Escalation tactic, the analysis identified Exploitation for Privilege Escalation (T1068) with moderate confidence (50%), supported by evidence indicating flaw breached tenant isolation in shared cloud infrastructure. Under the Credential Access tactic, the analysis identified Unsecured Credentials: Credentials In Files (T1552.001) with moderate to high confidence (70%), supported by evidence indicating residual data fragments could contain secrets handled by affected workloads. Under the Collection tactic, the analysis identified Data from Local System (T1005) with moderate to high confidence (80%), supported by evidence indicating residual disk data fragments (filesystem metadata, database pages, SQLite databases) and Data from Information Repositories (T1213) with moderate to high confidence (70%), supported by evidence indicating complete SQLite databases found in residual data. Under the Exfiltration tactic, the analysis identified Exfiltration Over C2 Channel (T1041) with lower confidence (40%), supported by evidence indicating no evidence of malicious exploitation or customer data compromise and Transfer Data to Cloud Account (T1537) with moderate confidence (50%), supported by evidence indicating cross-tenant data exposure in shared cloud infrastructure. Under the Defense Evasion tactic, the analysis identified Impair Defenses: Disable or Modify Tools (T1562.001) with moderate confidence (60%), supported by evidence indicating `skip_block_zeroing` option in dm-thin provisioning disabled block clearing. These correlations help security teams understand the attack chain and develop appropriate defensive measures based on the observed tactics and techniques.
Sources & References
- Cloudflare Rankiteo Cyber Incident Details: https://www.rankiteo.com/company/cloudflare/incident/CLO1790310238
- Cloudflare CyberSecurity Rating page: https://www.rankiteo.com/company/cloudflare
- Cloudflare Rankiteo Cyber Incident Blog Article: https://blog.rankiteo.com/clo1790310238-cloudflare-vulnerability-september-2026/
- Cloudflare CyberSecurity Score History: https://www.rankiteo.com/company/cloudflare/history
- Cloudflare CyberSecurity Incident Source: https://cybersecuritynews.com/cloudflare-containers-vulnerability/
- 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