CVE-2015-7833

What it actually does

The usbvision driver fails to validate the bInterfaceNumber field in a USB device descriptor, allowing a crafted descriptor to trigger a kernel panic and denial of service.

Why it matters to the business

A physically proximate attacker can crash affected Linux systems, causing unplanned downtime and requiring manual intervention to recover; the issue is limited to systems exposing the usbvision driver and has been public for over a decade with exploit code available.

How an attack unfolds

An attacker crafts a USB device descriptor containing a nonzero bInterfaceNumber value, connects the device to a vulnerable system, and triggers immediate kernel panic via the improperly validated input in the usbvision driver.

How to fix it

Upgrade the Linux kernel to a version that removes or properly validates the usbvision driver input; if upgrade is not feasible, blacklist the usbvision module via modprobe configuration and restrict physical USB port access.

How to confirm the fix worked

Verify kernel version is newer than the affected 3.10.0-123.20.1.el7 through 3.10.0-229.14.1.el7 range, confirm usbvision module is not loaded or is absent, and test with a benign USB device to ensure no panic occurs.

Typical attack path

1. Gain brief physical access to the target system
2. Connect a USB device presenting a crafted descriptor with nonzero bInterfaceNumber
3. Trigger usbvision driver processing that leads to kernel panic
4. Observe denial of service and reboot requirement

How to detect it

Review kernel logs and dmesg output for panic entries referencing usbvision or USB descriptor parsing failures; look for unexpected reboots coinciding with USB device insertion events.

• usbvision
• bInterfaceNumber
• kernel panic
• usbvision: probe of.*failed with error

What your security team should do

• Apply kernel updates or driver blacklisting on all affected RHEL and SUSE systems immediately
• Disable or physically secure USB ports on systems where the driver cannot be removed
• Monitor kernel logs for usbvision-related panic messages as a compensating control