July 'Black Tuesday' overview

Published: 2007-07-10
Last Updated: 2007-07-12 10:00:53 UTC
by Swa Frantzen (Version: 2)
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Overview of the July 2007 Microsoft patches and their status.

# Affected Contra Indications Known Exploits Microsoft rating ISC rating(*)
clients servers
MS07-036 Multiple vulnerabilities allow remote code execution with the rights of the logged on user.
Replaces MS07-023

KB 936542 No known exploits Critical Critical Important
MS07-037 Input validation failure  allows remote code execution with the rights of the logged on user
Publisher 2007

KB 936548
No known exploits Important Critical(***) Important
MS07-038 Teredo interfaces bypass certain firewall rules leading to exposure of the system's interfaces and bypass of the perimeter defenses due to the tunneling.

KB 935807
No known exploits Moderate Critical Critical(**)
MS07-039 Multiple input validation failures allow remote code execution and DoS.
Active Directory Servers

KB 926122 No known exploits Critical Important(**) Critical
MS07-040 Multiple vulnerabilities allow remote code execution on clients and information disclosure on servers.
Replaces MS05-004
.NET framework


Please read the KB and those it references below, readers are reporting various issues.

KB 931212

No known exploits Critical Critical Critical
MS07-041 Buffer overflow allows remote code execution with system level privileges.
IIS 5.1
(Web server on windows XP)

KB 939373
DoS exploit public since 2005 Important Critical(***) Critical(***)


We will update issues on this page as they evolve.
We appreciate updates
US based customers can call Microsoft for free patch related support on 1-866-PCSAFETY
(*): ISC rating
  • We use 4 levels:
    • PATCH NOW: Typically used where we see immediate danger of exploitation. Typical environments will want to deploy these patches ASAP. Workarounds are typically not accepted by users or are not possible. This rating is often used when typical deployments make it vulnerable and exploits are being used or easy to obtain or make.
    • Critical: Anything that needs little to become "interesting" for the dark side. Best approach is to test and deploy ASAP. Workarounds can give more time to test.
    • Important: Things where more testing and other measures can help.
    • Less Urgent: Typically we expect the impact if left unpatched to be not that big a deal in the short term. Do not forget them however.
  • The difference between the client and server rating is based on how you use the affected machine. We take into account the typical client and server deployment in the usage of the machine and the common measures people typically have in place already. Measures we presume are simple best practices for servers such as not using outlook, MSIE, word etc. to do traditional office or leisure work.
  • The rating is not a risk analysis as such. It is a rating of importance of the vulnerability and the perceived or even predicted threat for affected systems. The rating does not account for the number of affected systems there are. It is for an affected system in a typical worst-case role.
  • Only the organization itself is in a position to do a full risk analysis involving the presence (or lack of) affected systems, the actually implemented measures, the impact on their operation and the value of the assets involved.
  • All patches released by a vendor are important enough to have a close look if you use the affected systems. There is little incentive for vendors to publicize patches that do not have some form of risk to them.

(**): in the event Vista based machines are used as a server, or in the unlikely event Active Directory Services are running on machines used as clients.

(***):If installed.

Swa Frantzen -- NET2S

Keywords: mspatchday
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IE vs. FF

Published: 2007-07-10
Last Updated: 2007-07-11 11:16:33 UTC
by Swa Frantzen (Version: 3)
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No, I'm not restarting the browser wars. They have been fought and lost.

Let's look at a recently published exploit though:

When Firefox installs on windows, it installs itself as a URL handler a few times. In pseudo code the handler that is added looks like:

FIREFOX.EXE -option "%1"  -option

Now what happens if  %1 contains a double quote?
Right, the attacker can add more options.

So where does IE come into play against Firefox ?
IE happily calls the URL handler and as such provides a path to add additional options that lead to increased scripting rights inside Firefox.

As a result the IE user on a machine that has Firefox installed is at risk.

A workaround is to remove the URL handlers installed by Firefox from the registry.

This however goes to show that even unused but installed client programs might be a threat on your client system. Hence you need to take care of vulnerabilities in software that you don't even use.


  • A reader pointed us to Jesper's blog having a set of of commands to remove the URL handlers.
  • Giorgio Maone explained how NoScript -which we recommended numerous times already-, does protect from this since May 22nd 2007. Thanks a lot for the clarifications!

Swa Frantzen -- NET2S

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WinPcap local privilege escalation

Published: 2007-07-10
Last Updated: 2007-07-10 21:15:55 UTC
by Swa Frantzen (Version: 1)
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An exploit has been made public for a privilege escalation in WinPcap, a DLL used by many security tools.

Even if we agree most systems security professionals would use this on, will typically not have many untrusted users and as such will escape he worst of this. Still, a local escalation and a remote user level exploit combined might be bad enough to get such security systems exploited.

Better be safe than sorry.

WinPcap version 4.0.1 should fix this.

Swa Frantzen -- NET2S

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