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Abstract

This report details a fatal design flaw in the iCloud synchronization engine where an “authorized” operation leads to permanent database corruption and a Denial of Service (DoS) across the ecosystem. By leveraging AI as a strategic partner, I successfully navigated the Apple Product Security team’s defense logic to obtain an admission of a “Product Issue.”

1. The Trigger: Physical Anomaly to Digital Forensics

It started with a hardware warning: “Unknown Camera Part” on a freshly initialized iPhone. This physical rejection led to a deep dive into the iCloud logs of a brand-new Apple ID, revealing a catastrophic collapse of the cloud infrastructure.

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Fig 1. The Physical Vector: An “Unknown Part” warning triggered by unauthorized camera pipeline intervention, serving as the hardware-level evidence of the attack.

2. The Anomaly: The “27.2KB” Magic Number

In a clean environment with zero legacy data, a specific pattern emerged:

• The “Dead” Database: HealthKit databases across all synced devices were reduced to a fixed size of 27.2KB.

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Fig 2. The 27.2KB corruption observed in HealthKit logs

• Integrity Failure: This wasn’t a “deletion” but a “corruption.” The database structure was permanently altered into an inconsistent state.
• Denial of Service (DoS): The sync engine broadcasted the corrupted index to other devices (iPad), causing client apps to white-out and become unresponsive.

3. The Logical Battle: Integrity & Availability vs. Authorization

Apple’s initial response was a standard dismissal: “Authorized operation.” They argued that any action taken with a passcode is by definition “intended.”

I challenged this dogma using the CIA Triad as my primary weapon:

• Integrity: Does Apple’s infrastructure allow a user to persist a corrupted database state? If so, the system fails to guarantee data integrity.
• Availability: Does an authorized login grant a “license to freeze” the entire ecosystem? A single device’s operation should never compromise the availability of other synced nodes. Fig 3. Challenging the Systemic Integrity Failure Logic: A rebuttal arguing that the persistent loss of records and ecosystem-wide DoS cannot be reduced to simple “user behavior.”

4. AI as the Strategic Chief of Staff

The most critical part of this journey was the collaboration with AI (Gemini).

• Initial Resistance: Even the AI initially sided with Apple, suggesting it was “intended behavior.”
• The Breakthrough: By presenting the “27.2KB” evidence and debating architectural principles for hours, I “re-trained” the AI’s perspective.
• The Result: The AI evolved from a translator into a Strategic Partner, converting architectural passion into cold, professional English that silenced the giant’s defense.

5. Conclusion: From “Spec” to “Product Issue”

Following a 120-hour forensic investigation, Apple finally acknowledged the situation as a “Product Issue.” This case proves that an individual architect, armed with logic and AI, can hold global platforms accountable for their architectural failures.

Fig 4. Exclusion from the Security Bounty Program: Apple explicitly excludes synchronization and performance issues from its bounty scope, categorizing them as non-security “Product Issues.”

Original Japanese Report (Zenn)

For those interested in the initial forensic process and the community discussion in Japan, the original Japanese article can be found here: 認可された操作が可用性を奪う時：AIと共闘しAppleの防衛論理を突破した「iCloud不整合」の全記録