iOS TCC Framework Bypass – Undocumented kTCCServiceLiverpool Access

Overview

This repository documents a critical flaw in the iOS TCC (Transparency, Consent, and Control) framework that allows third-party applications to gain system-level privileges through an undocumented service, kTCCServiceLiverpool. This bypass occurs silently, without user consent, and is not visible in iOS Privacy Settings.

The issue was identified on iOS 26.1 through analysis of the TCC database (TCC.db) extracted from sysdiagnose logs. Multiple unrelated third-party apps have been observed with auth_reason=5 grants, which are normally reserved for Apple system processes.

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Security Disclosure & Tracking

• Reported to CERT-In: 2025-12-11
• Tracking ID: CERTIn-15336025

Affected Components

• Service: kTCCServiceLiverpool

• Apps Observed with Unauthorized System Bypass:

  • com.kentoh.hackerfeed
  • com.lifetimefitness.interests.ltfitness

• auth_reason: 5 (System Bypass Authority)

• Device Tested: iPhone 14 Pro Max, iOS 26.1

• Timeframe of Grants: 2024–2025

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Technical Analysis

Root Cause

The TCC framework incorrectly assigns auth_reason=5 to third-party apps due to a logic flaw in the authorization assignment routine. Key indicators of programmatic bypass include:

• pid: NULL – no associated process
• boot_uuid: UNUSED – not tied to a specific boot session
• last_reminded: never – no user prompt recorded

These metadata fields differ from standard TCC grants, which are tied to processes, sessions, and consent prompts.

Undocumented Service

kTCCServiceLiverpool is not listed in public TCC documentation and does not appear in Privacy Settings. Access to this service provides silent system-level privileges to third-party apps, creating a hidden vector for data access.

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Evidence

SQL Query to Identify Unauthorized Grants

SELECT client, service, auth_reason, datetime(last_modified, 'unixepoch') as last_modified
FROM access
WHERE auth_reason = 5
  AND client NOT LIKE 'com.apple.%'
  AND client NOT LIKE 'developer.apple.%';

Sample Findings

Application	Service	Last Modified
com.kentoh.hackerfeed	kTCCServiceLiverpool	2025-09-19T20:56:37Z
com.lifetimefitness.interests.ltfitness	kTCCServiceLiverpool	2025-05-26T21:34:15Z

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Impact

• Privilege Escalation: Third-party apps can bypass normal user consent.
• Privacy Risk: Apps can access sensitive services or telemetry without visibility.
• Persistence: Observed across multiple iOS updates.
• Detection Difficulty: Hidden from Privacy Settings; requires TCC database inspection.

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Recommendations

1. Audit TCC database for any unauthorized auth_reason=5 grants.
2. Revoke unauthorized grants and force user re-consent for affected apps.
3. Restrict auth_reason=5 exclusively to Apple-signed system services.
4. Document or restrict kTCCServiceLiverpool in official TCC framework documentation.
5. Add runtime assertions to prevent unauthorized assignment of system bypass authority.

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Reproduction Steps

1. Generate a sysdiagnose log on an iOS 26.1 device.
2. Extract TCC.db from sysdiagnose_*/logs/Accessibility/.
3. Run the SQL query above to identify third-party apps with auth_reason=5.
4. Confirm unauthorized access to kTCCServiceLiverpool for affected apps.

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