CVE-2022-29246
📋 TL;DR
CVE-2022-29246 is a buffer overflow vulnerability in Azure RTOS USBX's DFU UPLOAD functionality that allows attackers to bypass security features or execute arbitrary code. It affects all systems using Azure RTOS USBX versions prior to 6.1.11 with USB DFU functionality enabled. The vulnerability occurs when handling DFU UPLOAD commands with oversized data transfers.
💻 Affected Systems
- Azure RTOS USBX
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through arbitrary code execution, allowing attackers to take full control of affected devices and potentially pivot to other systems.
Likely Case
Denial of service through system crashes or memory corruption, with potential for limited code execution in specific configurations.
If Mitigated
No impact if patched or proper buffer boundary checks are implemented in custom implementations.
🎯 Exploit Status
Exploitation requires USB access to the device but no authentication. The vulnerability is straightforward to trigger with crafted DFU UPLOAD commands.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.1.11
Vendor Advisory: https://github.com/azure-rtos/usbx/security/advisories/GHSA-hh5p-x584-j8hv
Restart Required: Yes
Instructions:
1. Download USBX version 6.1.11 or later from official repository. 2. Replace vulnerable USBX components in your project. 3. Recompile and redeploy firmware. 4. Restart affected devices.
🔧 Temporary Workarounds
Buffer Size Alignment
allManually align request and buffer sizes to ensure buffer boundaries are respected in the ux_device_class_dfu_control_request function.
Modify ux_device_class_dfu_control_request.c to add boundary checks before processing UX_SLAVE_CLASS_DFU_COMMAND_UPLOAD
🧯 If You Can't Patch
- Disable USB DFU functionality if not required for device operation
- Implement network segmentation to isolate USB-connected devices from critical systems
🔍 How to Verify
Check if Vulnerable:
Check USBX version in source code or compiled firmware. If version < 6.1.11 and DFU functionality is enabled, system is vulnerable.Check Version:
Check USBX_VERSION_MAJOR, USBX_VERSION_MINOR, USBX_VERSION_PATCH in ux_api.h or project configurationVerify Fix Applied:
Verify USBX version is 6.1.11 or later and examine ux_device_class_dfu_control_request.c for proper buffer boundary checks.📡 Detection & Monitoring
Log Indicators:
- Multiple failed DFU operations
- Unexpected device resets after USB connections
- Memory access violation logs
Network Indicators:
- Unusual USB traffic patterns
- DFU commands with abnormally large wLength values
SIEM Query:
Device logs containing 'DFU UPLOAD' with size > 256 OR memory violation errors after USB connection🔗 References
- https://github.com/azure-rtos/usbx/blob/master/common/usbx_device_classes/src/ux_device_class_dfu_control_request.c
- https://github.com/azure-rtos/usbx/releases/tag/v6.1.11_rel
- https://github.com/azure-rtos/usbx/security/advisories/GHSA-hh5p-x584-j8hv
- https://github.com/azure-rtos/usbx/blob/master/common/usbx_device_classes/src/ux_device_class_dfu_control_request.c
- https://github.com/azure-rtos/usbx/releases/tag/v6.1.11_rel
- https://github.com/azure-rtos/usbx/security/advisories/GHSA-hh5p-x584-j8hv
