CVE-2022-48757

What it actually does

The vulnerability allows packet_type entries created by unbound packet sockets in one network namespace to be visible when reading /proc/net/ptype from other namespaces due to missing net namespace isolation in ptype_seq_show.

Why it matters to the business

Attackers with access to multiple network namespaces on the same Linux system can observe limited metadata about packet socket usage, potentially aiding reconnaissance in containerized or multi-tenant environments; the issue affects a wide range of Linux kernel deployments with moderate operational exposure given its age and low exploit probability.

How an attack unfolds

An attacker creates a packet socket in one net namespace without binding it to a device, then from a separate namespace reads /proc/net/ptype to observe the leaked packet_type; the listed threat actor reference appears unrelated to this disclosure issue.

How to fix it

Update the Linux kernel to a version containing commit 8f88c78d24f6f346919007cd459fd7e51a8c7779 or later; rebuild and deploy the patched kernel across all affected systems, prioritizing those with heavy use of network namespaces.

How to confirm the fix worked

Confirm the kernel source contains the net pointer addition to packet_type and the corresponding check in ptype_seq_show; verify /proc/net/ptype output is isolated between namespaces after applying the update.

Typical attack path

1. Gain access to a Linux system supporting network namespaces
2. Create packet socket in one namespace without device binding
3. Switch to or access another namespace
4. Read /proc/net/ptype to observe leaked packet_type metadata

How to detect it

Review system logs and process activity for unexpected packet socket creation across namespaces; examine /proc/net/ptype contents from multiple namespaces for unexpected entries after socket creation in another namespace.

What your security team should do

• Apply the kernel patch containing commit 8f88c78d24f6f346919007cd459fd7e51a8c7779 as soon as possible on production systems
• Audit environments using multiple network namespaces for exposure
• Monitor upstream stable kernel releases for backports of this fix