CVE-2024-53099

What it actually does

Out-of-bounds array access in bpf_link_show_fdinfo() when an unregistered link type is encountered, allowing potential memory corruption or information disclosure in the Linux kernel BPF subsystem.

Why it matters to the business

May cause system instability, crashes, or limited information leaks on Linux-based servers and devices, increasing operational risk and downtime especially in environments with high Linux kernel prevalence and custom BPF usage.

How an attack unfolds

An attacker with local access crafts or triggers a BPF link of an unregistered type to invoke bpf_link_show_fdinfo(), bypassing the missing BPF_LINK_TYPE() registration check and performing an out-of-bounds read; listed threat actors in espionage or financially motivated campaigns could leverage similar kernel memory issues.

How to fix it

Apply kernel updates addressing the missing validity check; for listed affected products upgrade apache2 on Ubuntu 14.04 LTS to 2.4.7-1ubuntu4.15 and on Ubuntu 16.04 LTS to 2.4.18-2ubuntu3.2.

How to confirm the fix worked

Confirm kernel version includes the bpf_link_show_fdinfo() validity check; test by attempting to exercise unregistered link types and verify absence of warnings or OOB accesses.

Typical attack path

1. Obtain local access or execute code on a target Linux system
2. Create or manipulate a BPF link object without proper type registration
3. Trigger fdinfo display or related BPF introspection
4. Exploit resulting out-of-bounds memory access for corruption or disclosure

How to detect it

Search kernel logs for warnings or oops mentioning bpf_link_show_fdinfo or bpf_link_type_strs; review BPF program load and link creation events for anomalies, incorporating context from known Linux kernel memory access campaigns.

What your security team should do

• Prioritize kernel updates on all Linux systems within 30 days given publication age
• Audit BPF usage for custom link types and ensure BPF_LINK_TYPE() registration
• Monitor for kernel oops or warnings related to bpf_link_type_strs
• Review and restrict unprivileged BPF access where feasible