nf_tables UAF → kernel R/W → root

§ Context

Assumed environment: foothold as a regular user on Linux. Kernel < patch level for the nf_tables UAF. User namespaces enabled (default on most distros).

§ Steps

1. 01
   Spawn root shellInitial Access

   T1078— Valid Accounts
2. 02
   Low-priv user shellInitial Access

   T1078— Valid Accounts
3. 03
   Overwrite current cred structExecution

   T1059— Command and Scripting Interpreter
4. 04
   Create user + net namespacePrivilege Escalation

   L-CAP-ABUSE— Linux Capability Abuse
5. 05
   Trigger nf_tables UAFPrivilege Escalation

   LK-NETFILTER-UAF— netfilter / nf_tables UAF
6. 06
   Build kernel R/W primitivePrivilege Escalation

   LK-DIRTY-PAGETABLE— Dirty Pagetable
7. 07
   Win race via userfaultfd suspendPrivilege Escalation

   LK-USERFAULTFD— userfaultfd Race

§ References

• T1078Valid Accounts
• T1059Command and Scripting Interpreter

§ Frequently asked

What is the "nf_tables UAF → kernel R/W → root" attack path?

CVE-2024-1086-class nf_tables UAF reachable from a user namespace. Win the race with userfaultfd to land an attacker object in the freed slot, build a kernel R/W primitive, overwrite the current task's cred struct. It chains 7 steps drawn from real-world offensive-security techniques.

What starting position does this attack require?

The first step is Spawn root shell (T1078) — a initial access primitive. Assumed environment: foothold as a regular user on Linux.

What is the final impact of this kill-chain?

The final step lands on Win race via userfaultfd suspend (LK-USERFAULTFD), which falls under Privilege Escalation. From here, an operator typically pivots into post-exploitation or maintains persistence.

How can defenders detect or prevent this attack?

Detection and prevention vary per step. Refer to each linked MITRE ATT&CK entry under "References" — every technique on that page lists defensive controls, detection telemetry, and known threat-actor usage.

§ Related dossiers

• Shared techniques3

  io_uring UAF → modprobe_path overwrite → root

  Use an io_uring UAF to land arbitrary kernel write, repoint /proc/sys/kernel/modprobe to an attacker binary, then trigger a kernel auto-modprobe — runs the binary as root.

• Shared techniques2

  Process doppelgänging → spawn signed image with attacker bytes

  Use NTFS transactional file APIs to overlay an attacker image during process creation. The final mapped process differs from the on-disk file — AV sees only the legit signed image at scan time.

• Shared techniques2

  BYOVD → kernel-level disable of EDR callbacks

  From local admin, load a signed-but-vulnerable driver. Use its kernel primitive to walk the EDR's PsSetCreateProcessNotifyRoutine entries and unlink them — EDR stops receiving events while still 'running'.

• Shared techniques2

  certutil + bitsadmin → AV-friendly stager chain

  Initial access dropped a tiny .bat. It uses certutil to decode a base64 blob and bitsadmin to fetch the real beacon, then schtasks for persistence. Every binary is signed Microsoft.

• Shared techniques2

  F5 BIG-IP iControl auth bypass (CVE-2022-1388) → root on LB

  Connection-header smuggle bypasses iControl REST auth, command-injection RCE as root. Load balancers see all traffic — recover TLS keys, session cookies, internal SSO config.

• Shared techniques2

  Exposed UART → root shell → firmware extraction

  Open the IoT device, locate TX/RX/GND pads, attach a USB-UART, get an unauthenticated root prompt, dump firmware for offline analysis + 0-day hunting.