Bug 161750 - net-anlyzer/snort [2.6.1 <= 2.6.1.2] Integer underflow in DecodeGRE()
Bug#: 161750 Product:  Gentoo Security Version: unspecified Platform: All
OS/Version: Linux Status: RESOLVED Severity: trivial Priority: P2
Resolution: FIXED Assigned To: security@gentoo.org Reported By: aetius@gentoo.org
Component: Vulnerabilities
URL:  http://labs.calyptix.com/advisories/CX-2007-01.txt
Summary: net-anlyzer/snort [2.6.1 <= 2.6.1.2] Integer underflow in DecodeGRE()
Keywords:  
Status Whiteboard: C4 [noglsa]
Opened: 2007-01-12 13:39 0000
Description:   Opened: 2007-01-12 13:39 0000 
Snort contains an integer underflow in the new GRE processing code, allowing
possible log corruption or information disclosure.

Reproducible: Didn't try

Steps to Reproduce:

------- Comment #1 From Matt Drew 2007-01-12 13:41:32 0000 ------- 
Setting status and cc'ing herd.  The advisory says there's a patch in snort
CVS.

------- Comment #2 From Raphael Marichez 2007-01-13 23:25:25 0000 ------- 
Fixed in r 1.131 of decode.c, see attached upstream patch.

The vulnerable GRE support has been introduced in 2.6.1

There is no vulnerable stable version in the portage tree (latest stable ebuild
= 2.4.5)

But this will be important to consider since there is bug 161632 which concerns
a DoS that has been fixed in 2.6.1

------- Comment #3 From Raphael Marichez 2007-01-13 23:26:40 0000 ------- 
Created an attachment (id=106865) [details]
Upstream patch

------- Comment #4 From Raphael Marichez 2007-01-13 23:53:58 0000 ------- 
BTW the gentoo ebuild doesn't take the advantage of --enable-gre which is too
bad :(

i'm going to attach a backport of the upstream patch against 2.6.1.1, and an
ebuild patch for a "gre" USE-flag.


The vulnerability is only present with --enable-gre, so Gentoo is not actually
vulnerable. ("objdump -x decode.o | grep DecodeGRE" gives nothing).

------- Comment #5 From Raphael Marichez 2007-01-13 23:56:55 0000 ------- 
Created an attachment (id=106867) [details]
Backport for 2.6.1.1

------- Comment #6 From Raphael Marichez 2007-01-14 00:04:53 0000 ------- 
Created an attachment (id=106869) [details]
Proposed ebuild with --enable-gre support

------- Comment #7 From Matthias Geerdsen 2007-03-07 13:32:15 0000 ------- 
This does not appear to be an issue anymore in the current stable 2.6.1.3-r1.
Reopen if you disagree.

c4 -> noglsa