Files
iOS-Activation-Flaw/README.md
Joseph Goydish II 6f3b80b117 Technical Write Up
2025-09-23 00:14:24 -04:00

76 lines
3.0 KiB
Markdown
Raw Blame History

This file contains invisible Unicode characters
This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
# Apple iOS Activation Infrastructure Vulnerability
## Overview
A **critical vulnerability** exists in Apples device activation infrastructure.  
The backend endpoint: 
https://humb.apple.com/humbug/baa
accepts **unauthenticated and unsigned XML property list (.plist) payloads**, exposing devices to **pre-activation tampering** during the setup phase.
## Impact
- **Arbitrary Provisioning:** Attackers can inject custom provisioning logic into the activation workflow.  
- **Bypass Security:** MDM enrollment, signature checks, and user consent are fully bypassed.  
- **Persistence:** Malicious profiles and configurations remain after activation.  
- **Attack Vectors:** Exploitable remotely via captive portals, rogue access points, or compromised provisioning servers.  
- **Techniques:** XML External Entity (XXE) injection, malformed payload acceptance, and silent background task injection.  
Server responses confirm consistent **HTTP 200 OK** acceptance of illicit payloads without validation.
---
## Risk
- **Enterprise & Supply Chain:** Devices can be manipulated before reaching end users.  
- **Stealth:** Changes are invisible to standard logs and forensic tools.  
- **High Severity:** Exploitation requires no jailbreak or physical access.  
---
## Evidence (Artifact-Based)
**Primary artifact:** `artifacts/mobileactivationd_sdcrt_baa_response.txt`  
Key observations from the server response:
- `HTTP Status Code: 200 (no error)` — confirms the endpoint accepted the request.  
- Headers: `Server: Apple`, `Host: humb.apple.com`, `HUMBUG_XHEADER_STATUS: 0`.  
- Response body contained multiple PEM certificate blocks (`-----BEGIN CERTIFICATE----- …`).  
- Timestamp in `Date:` header allows correlation with device/system logs.  
**Interpretation:** Instead of rejecting invalid/unsigned provisioning data, the server processed the request and returned cryptographic material, demonstrating insufficient validation.
---
## Attack Surface & Technical Impact
- **Pre-activation phase:** The flaw manifests before MDM enrollment or user consent.  
- **Delivery vectors:** captive portals, rogue Wi-Fi/APs, compromised provisioning servers.  
- **Technical outcomes:**  
  - Arbitrary provisioning injection  
  - Bypass of signature/consent enforcement  
  - Persistent, stealthy configuration drift in caches such as `CloudKitAccountInfoCache` and `CommCenter`  
---
## Detection
### Network Indicators
- Responses from `humb.apple.com/humbug/baa` with `200 OK` and PEM certificate blocks.  
- Presence of `HUMBUG_XHEADER_STATUS: 0` in response headers.
### Host Indicators
- Unexpected entries in:
  - `CloudKitAccountInfoCache`  
  - `CommCenter` modem/network configurations  
- Profiles/configs applied post-activation without user or MDM actions.
### Safe Triage Commands
```bash
# Search response captures for certificate blocks
grep -R "-----BEGIN CERTIFICATE-----" /path/to/response_captures/
# Look for humbug headers in activation logs
grep -i "HUMBUG_XHEADER_STATUS" /var/log/mobileactivationd*