CVE-2021-24086
This is a proof of concept for CVE-2021-24086 ("Windows TCP/IP Denial of Service Vulnerability "), a NULL dereference in tcpip.sys
patched by Microsoft in February 2021. According to this tweet, the vulnerability has been found by @piazzt. It is triggerable remotely by sending malicious UDP packet over IPv6.
You can read Microsoft's blog here: Multiple Security Updates Affecting TCP/IP: CVE-2021-24074, CVE-2021-24094, and CVE-2021-24086. It discusses briefly the impact and workaround/mitigations.
A more in-depth discussion about the root-cause is available on doar-e.github.io: Reverse-engineering tcpip.sys: mechanics of a packet of the death (CVE-2021-24086).
Running the PoC
Run the cve-2021-24086.py
script; it requires Scapy:
over@bubuntu:~$ sudo python3 cve-2021-24086.py
66 fragments, total size 0xfff8
..................................................................
Sent 66 packets.
.
Sent 1 packets.
Authors
- Axel '@0vercl0k' Souchet