On October 20, 2025, Amazon Web Services (AWS) experienced a widespread outage centered on the “US-EAST-1 (Northern Virginia)” region in the United States. This outage temporarily made inaccessible numerous online services worldwide, including social media, gaming, payment systems, communications, and government services. The impact extended beyond the U.S., affecting users globally, including in Japan, where intermittent delays and connection failures were observed. AWS announced that recovery operations were completed within the same day and that all services had returned to normal. In this article, we examine what happened, the root cause, and the lessons learned—especially in terms of risk management that should be discussed by governments and companies.
Root Cause
Based on AWS’s official statements and various reports, the main causes were:
- The outage originated in the US-EAST-1 region, affecting several core services installed there.
- Issues related to DNS (Domain Name System) were particularly highlighted.
- In summary: DNS/API endpoint resolution failures and health check malfunctions led to cascading failures in downstream services and server access.
Issues Highlighted by This Incident (Including Security and Operations)
This outage revealed critical challenges in cloud service operations and security management:
- Infrastructure Concentration Risk (Single Point of Failure)
- Heavy reliance on AWS meant that a failure in one region had global repercussions.
- DNS failure led to downstream service outages, showing the need for cross-provider redundancy and regional distribution.
- Weakness in Operational Monitoring Subsystems
- The health monitoring subsystem of the load balancer was the initial failure point.
- Monitoring systems themselves must be fault-tolerant to prevent cascading failures.
- Importance of Integrity and Isolation Beyond Availability
- Although availability was maintained, poor integrity and isolation allowed the issue to spread.
- Structural separation is key to ensuring one service’s failure doesn’t affect others.
- Visibility of Dependencies and Risk Assessment
- Many companies were unaware of which AWS regions, services, or subsystems they depended on.
- The incident exposed hidden dependency structures that can lead to service outages.
- Security Management Challenges
- Although not caused by a cyberattack, the incident offers lessons:
- Monitoring and health check subsystems must be protected and redundant.
- Users must design resilience plans in case a cloud region fails.
- Operational errors and subsystem failures can lead to service outages and loss of trust, making configuration management a vital part of security.
Challenges Faced by Japanese Companies
Legal and Regulatory Concerns
(1) Data Sovereignty
Many Japanese companies prefer to manage and store personal and confidential data within Japan. However, foreign cloud vendors often back up or replicate data in overseas regions. This raises concerns about foreign government access under laws like the U.S. CLOUD Act.
(2) Compliance with Japan’s Personal Information Protection Law
The law requires user consent or appropriate safeguards for overseas data transfers. Cloud users often cannot fully track data routes or storage locations, making legal accountability difficult—especially in healthcare, finance, and public sectors.
(3) Ambiguity in Contracts and Responsibility
Responsibility during outages or data leaks is often unclear. AWS uses a “Shared Responsibility Model,” which many companies misunderstand, leading to confusion over insurance and compensation.
Concerns About Data Location and Operational Management
(1) Risk of Overseas Servers
Japanese companies struggle to visualize where data is physically stored. Geopolitical risks (e.g., U.S.-China tensions) increase anxiety about foreign data centers. Time zone differences also complicate incident response.
(2) Difficulty in Operational Audits and Traceability
Audit logs and access records provided by cloud vendors are limited. Internal security audits and SOC audits for financial institutions face challenges due to cloud operations being a “black box.”
(3) Limitations of SLA (Service Level Agreements)
SLAs promise high uptime (e.g., 99.9%) but don’t cover actual business losses. Companies must absorb the impact of service disruptions themselves.
Cultural Gaps in Information Handling
(1) Differences in Information Protection Culture
Japanese companies emphasize internal data retention and strict access control, while foreign cloud vendors prioritize convenience, speed, and openness. This mismatch delays cloud adoption.
(2) Challenges with Multilingual and Multi-Jurisdictional Compliance
Contracts and privacy policies are often in English, making it hard for Japanese legal teams to understand. SMEs especially struggle with legal terminology and foreign laws.
Security and Availability Concerns
(1) Lack of Visibility (Black Box Effect)
Cloud users can’t easily verify how data is processed or backed up. In cases like the AWS outage, users don’t receive timely details about the cause.
(2) Risk of Internal Misconfigurations
Data leaks often result from user-side errors (e.g., misconfigured S3 buckets). Even with secure technology, poor access control poses risks.
(3) Vendor Lock-in Due to Cloud Dependence
Once migrated to AWS or Azure, companies face difficulty switching due to proprietary data structures and APIs. This creates structural dependence, reducing flexibility and bargaining power.
Summary: Future Directions & strategy
Japanese companies are more concerned about legal risks, governance, accountability, and cultural consistency than about technical reliability. As a result, there has been a growing trend recently to prefer domestic clouds and government-certified clouds (ISMAP certified). While this is a challenge faced by many global companies that adhere to nationalism, simply imposing the headquarters’ way of doing things will not increase sales or generate profits. Now more than ever, it is necessary to thoroughly understand the culture and legal risks of the target market and respond flexibly while finding compromises. Management teams are required to have a solid corporate strategy to avoid becoming obsessed with short-term profits and suffering major damage from litigation issues.
