By Ryan Naraine
July 11, 2006
A mega update for the widely used Excel spreadsheet program is the
highlight of the latest batch of security patches issued by Microsoft on
One month after confirming that maliciously rigged Excel files were being
used in targeted zero day attacks against businesses, Microsoft released a
"critical" bulletin with patches for eight distinctly different Excel
The MS06-037 bulletin covers a wide range of "remote code execution" flaws
that could let hackers take "complete control of the vulnerable client
"We recommend that customers apply the update immediately," Microsoft
Affected software packages include Office 2003 (SP1 and SP2), Office XP
(SP3), Office 2000 SP3, Office 2004 for Mac and Excel v. X for Mac.
The Excel bulletin replaces the MS06-012 update issued in March 2006 to
correct two more flaws in the way Office handles PNG and GIF image files.
The Microsoft Office software suite is a main focus of July's Patch Day.
In addition to the Excel bulletin, the company released MS06-038 to cover
three malformed string parsing Office bugs and MS06-039 to correct two
more flaws in the way Office handles PNG and GIF image files.
Over the last four months, the company has patched a whopping 19 flaws in
the Microsoft Office software suite.
Microsoft has also slapped a "critical" rating on the MS06-036 bulletin
that deals with a buffer overrun in the DHCP (Dynamic Host Configuration
Protocol) Client service.
This could allow remote code execution on Windows 2000 SP4, Windows XP and
Windows Server 2003, Microsoft warned.
Windows uses DHCP to reduce the complexity of administering network
addresses but because of an unchecked buffer, Microsoft said an attacker
could remotely hijack a compromised system to install programs; view,
change, or delete data; or create new accounts with full user rights.
A fifth "critical" bulletin, MS06-035, also provides patches for a pair of
remote code execution issues in the Windows Server Service.
Security experts believe one of the two Server Services bug a heap
overflow in Mailslotcould prove problematic.
"That's the one to watch," said Marc Maiffret, chief hacking officer of
eEye Digital Security. "It's a nasty wormable bug."
Affected OS versions includes Windows 2000 SP4, Windows XP and Windows
The July patch batch also includes:
* MS06-033 - An "important" update with fixes for an information
disclosure flaw in ASP.NET. This affects users of the Microsoft Windows
NET Framework 2.0 and applies to Windows 2000 SP4, Windows XP and
Windows Server 2003.
* MS06-034 - Patches for a vulnerability in Microsoft Internet Information
Services using ASP. This could allow remote code execution attacks but
is only rated "important" because attackers would require valid logon
credentials to launch a successful exploit.
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