CVE-2024-42312

What it actually does

Failure to initialize i_uid/i_gid fields in sysfs inodes within the sysctl core allows use of uninitialized values when set_ownership() skips assignment, leading to memory corruption.

Why it matters to the business

Local users on affected Linux systems may trigger kernel instability or crashes, resulting in denial of service for services and potential data loss on systems that cannot tolerate downtime.

How an attack unfolds

An attacker with local access crafts sysctl or /proc/sys operations that invoke net_ctl_set_ownership() or similar paths where initialization was skipped, causing the kernel to dereference or act on uninitialized uid/gid values and corrupt memory structures.

How to fix it

Update the Linux kernel to a version containing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 or later; rebuild and deploy the updated kernel across all affected systems.

How to confirm the fix worked

Confirm the running kernel source contains commit 0ecfebd2b52404ae0c54a878c872bb93363ada36; verify sysfs inode initialization code in fs/sysfs and fs/proc/proc_sysctl.c now sets defaults unconditionally.

Typical attack path

1. Obtain local shell access on a vulnerable Linux system
2. Interact with sysctl interfaces or /proc/sys entries that trigger set_ownership() paths
3. Trigger the code path where i_uid/i_gid remain uninitialized
4. Cause kernel memory corruption leading to panic or denial of service

How to detect it

Review kernel logs for oops or panic entries referencing sysctl, proc_sysctl, or uninitialized inode fields; examine audit logs for unusual sysctl or /proc/sys access patterns by local processes.

What your security team should do

• Prioritize kernel updates on all internet-facing and multi-user Linux hosts within the next patching cycle
• Monitor upstream stable kernel releases for backports of the fix commit
• Restrict unprivileged local access where feasible until patches are applied