CVE-2015-1420

What it actually does

The vulnerability is a race condition in the Linux kernel's handle_to_path function that permits a local attacker to modify the handle_bytes value mid-execution, bypassing size checks and allowing reads from additional memory locations.

Why it matters to the business

This flaw can lead to unauthorized disclosure of sensitive kernel memory contents on affected Linux systems, potentially exposing confidential data without requiring elevated privileges; the issue remains relevant for legacy deployments despite its age.

How an attack unfolds

An attacker with local access crafts a file handle and races the handle_to_path function by altering handle_bytes during execution to read beyond intended boundaries.

How to fix it

Upgrade the Linux kernel to a version beyond 3.19.1 where the race condition is addressed. Apply available security patches for affected distributions such as Debian.

How to confirm the fix worked

Verify the running kernel version is newer than 3.19.1 and test that the handle_to_path function properly enforces size restrictions.

Typical attack path

1. Obtain local access to the system
2. Identify vulnerable kernel version through 3.19.1
3. Exploit race condition in fs/fhandle.c to leak memory

How to detect it

Examine system logs for unusual handle operations or memory access patterns; monitor for processes attempting to manipulate file handles in fs/fhandle.c related functions.

What your security team should do

• Prioritize kernel updates on all Linux hosts
• Monitor for local information disclosure attempts
• Review system logs for unusual file handle operations