现已发现在OpenBSD的所有活动Release版本中，pf防火墙有个安全漏洞，可能引致DoS攻击，导致内核崩溃。
目前OpenBSD开发小组已经放出了修补补丁：。
这个漏洞主要涉及到网络地址和协议的转换，临时解决办法：按IPv4和IPv6分别指定网络协议。
例：
nat/rdr ... inet proto { tcp udp icmp } ...
nat/rdr ... inet6 proto { tcp udp icmp6 } ...
从补丁文件的日期来看，这个漏洞从2008年8月就出现了。
下面是对这个漏洞的详细说明：
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 :
CVE :
ISS X-Force: :
BID :
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 |
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