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Workaround for Multiple Microsoft Office Excel BIFF4, BIFF5, and BIFF6 Records Vulnerabilities (MS11-021)

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Check Point Reference: SBP-2011-06
Date Published:
Preemptive Since:
Severity:
Last Updated:
Source: Microsoft Security Bulletin MS11-021
Industry Reference(s): CVE-2011-0097
CVE-2011-0098
CVE-2011-0103
Protection Provided by: Security Gateway
  • R75
  • R71
  • R70
VPN-1
  • NGX R65
VSX
  • NGX R65
IPS-1
  • IPS-1
  • IPS-1 NGX R65
Who is Vulnerable?
Microsoft Excel 2002 SP3
Microsoft Excel 2003 SP3
Microsoft Excel 2007 SP2
Microsoft Exce 2010 (32-bit editions)
Microsoft Excel (64-bit editions)
Microsoft Office 2004 for Mac
Microsoft Office 2008 for Mac
Open XML File Format Converter for Mac
Microsoft Excel Viewer SP2
Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2
Vulnerability Description
Multiple memory corruption vulnerabilities have been identified in Microsoft Excel. Microsoft Excel is a popular spreadsheet application. A remote attacker could exploit these issues via a malformed Excel file. Successful exploitation of these vulnerabilities may allow execution of arbitrary code on a target system.
Update/Patch Available
Apply patches:
Microsoft Security Bulletin MS11-021 
Vulnerability Details
The vulnerabilities are due to a memory handling error in Microsoft Office Excel during validation of record information while parsing a specially crafted Excel file. A remote attacker could trigger this flaw by convincing a victim to open a malicious Office file. Successful exploitation of this issue may corrupt system memory, allowing execution of arbitrary code on a vulnerable system.

Protection Overview
This protection will detect and block XLS BIFF4, BIFF5, and BIFF6 files. No update is required to address this vulnerability.

Since the protection offered in this advisory may degrade performance and block access to legitimate files, users are advised to use this protection as a workaround till all systems are patched.  

Users are protected against this vulnerability if the protection for blocking Legacy Office Excel Files addressed in SBP-2009-22 has been applied.

To configure the defense, select your product from the list below and follow the related protection steps.

Security Gateway: R75

How Can I Protect My Network?
1. In the IPS tab, click Protections > By Protocol > IPS Software Blade > Application Intelligence > Content Protection.
2. In the right pane, double-click the Microsoft Office Excel Legacy Files protection.
3. In the Protection Details window, click on Edit. Choose the protection's Action (Override IPS Policy with: Prevent/Detect), and apply Additional Settings. 
4. Install policy on all modules.

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: Content Protection Violation
Attack Information: Microsoft Office Excel legacy file

Security Gateway: R70/R71

How Can I Protect My Network?
1. In the IPS tab, click Protections > By Protocol > Application Intelligence > Content Protection.
2. In the right pane, double-click the Microsoft Office Excel Legacy Files protection.
3. In the Protection Details window, click on Edit. Choose the protection's Action (Override IPS Policy with: Prevent/Detect), and apply Additional Settings. 
4. Install policy on all modules.

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: Content Protection Violation
Attack Information: Microsoft Office Excel legacy file

VPN-1 NGX R65 & VSX NGX R65

How Can I Protect My Network?
1. In the SmartDefense tab, click Application Intelligence > Content Protection.
2. Select the following:

Microsoft Office Excel Legacy Files

3. In the configuration pane, under Settings > Mode, check Active.
4. Install policy on all modules.

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: Content Protection Violation
Attack Information: Microsoft Office Excel legacy file

IPS-1 & IPS-1 NGX R65

How Can I Protect My Network?
1. In the IPS-1 Policy Manager, click on the Protection tab.
2. In the Protection tree, click Application Intelligence > Badfiles, and select the Microsoft Office Parser protection group.
3. Click 
    Microsoft Excel 4.0 Workbook file detected (MS11-021)
    Microsoft Excel 7.0 Label Record Heap Overflow (MS11-021)
    Microsoft Office Excel RealTimeData Record Memory Corruption (MS11-021)

4. In the configuration pane, under Settings, check Active.
5. Click on Install Policy.

How Do I Know if My Network is Under Attack?
Upon attack, the following entries will be logged:

Alert Name: Vulnerability in MS-Office file
Description: Microsoft Excel 4.0 Workbook file detected (MS11-021)
                     Microsoft Excel 7.0 Label Record Heap Overflow (MS11-021)
                     Microsoft Office Excel RealTimeData Record Memory Corruption (MS11-021)