OpenBSD 4.3 up to OpenBSD-current: PF null pointer dereference - remote DoS (kernel panic)
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Helith - 0815
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Author : Rembrandt
Date : 2009-04-09
Affected Software: OpenBSD Kernel
Affected OS : OpenBSD 4.{3,4,5}, OpenBSD-current
Propably older versions are affected as well
Type : Denial of Service
OSVDB :
Milw0rm : 8406
CVE :
ISS X-Force: :
BID : 34482
Secunia : 34676
VUPEN ID :
Trying to fix it responsible and get in contact with the vendor:
-- OpenBSD --
Contacted 2009-04-09 15:35 GMT+1
Patch avaiable 2009-04-11 23:43 UTC
We received no response nor a notification about an upcoming patch by
the developers.
-- END --
OpenBSDs PF firewall in OpenBSD 4.3 up to OpenBSD-current is prone to a
remote Denial of Service during a null pointer dereference in relation with
special crafted IP datagrams. If the firewall handles such a packet the kernel
panics.
Steps to reproduce:
If you are behind a OpenBSD firewall this nmap scan should trigger the problem
and crash your firewall device:
nmap -sO $some_host_so_that_the_firewall_handles_the_packets
For more informations please do read the patch issued by OpenBSD.
Patches and Workaround:
Patches are provided for OpenBSD 4.3, 4.4, 4.5 (upcoming, release 1st of may)
and OpenBSD-current (via CVS only) and are avaiable at the errata website.
The developers provide hints for a workaround at their errata website too.
Kind regards,
Rembrandt