Threat database

A malicious USB MTP/PTP device can cause the USBX host to read past a heap buffer during ordinary object enumeration, leaking adjacent heap contents to the application or faulting on an unmapped page.

A VideoStreaming interface reports the size of its whole class-specific descriptor block in the `wTotalLength` field of its input header. The USBX host recorded that figure and used it as the budget for walking the format, frame and frame-interval descriptors, without holding it against the configuration descriptor actually received. A device that reports a `wTotalLength` larger than the descriptors it supplies therefore had its own claim believed. Once the real bytes ran out the walk kept going, dereferencing the cursor past the end of the configuration buffer, in the host's context, whenever the application queried format or frame data.

A HID report descriptor is a sequence of items, each declaring in its header how many data bytes follow. The USBX host walks that sequence by advancing over each header and parsing the data behind it. The walk checked that an item fitted in the descriptor only **after** it had advanced past the header and parsed the payload, and the item analysis it relied on never measured the declared sizes against the bytes actually received. A HID peripheral returning a short report descriptor therefore drove a heap out-of-bounds read during ordinary enumeration.

The function _ux_host_class_storage_media_mount() is responsible for mounting partitions on a USB mass storage device. When it encounters an extended partition entry in the partition table, it recursively calls itself to mount the next logical partition. This recursion occurs in _ux_host_class_storage_partition_read(), which parses up to four partition entries. If an extended partition is found (with type UX_HOST_CLASS_STORAGE_PARTITION_EXTENDED or EXTENDED_LBA_MAPPED), the code invokes: _ux_host_class_storage_media_mount(storage, sector + _ux_utility_long_get(...)); There is no limit on the recursion depth or tracking of visited sectors. As a result, a malicious or malformed disk image can include cyclic or excessively deep chains of extended partitions, causing the function to recurse until stack overflow occurs.

Azure RTOS USBX is a USB host, device, and on-the-go (OTG) embedded stack, that is fully integrated with Azure RTOS ThreadX. An attacker can cause remote code execution due to out of bounds write vulnerabilities in Azure RTOS USBX. The affected components include functions/processes in host and device classes, related to CDC ECM and RNDIS in RTOS v6.2.1 and below. The fixes have been included in USBX release 6.3.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.