Update Protection against Microsoft Windows SMB mrxsmb.sys Remote Heap Overflow Vulnerability (MS11-019)

Vulnerability
Protection

Check Point Reference:	CPAI-2011-018
Date Published:
Severity:
Last Updated:
Source:	Microsoft Security Bulletin MS11-019
Industry Reference(s):	CVE-2011-0654
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 Windows XP SP3 Microsoft Windows Server 2003 SP2
Vulnerability Description A heap buffer overflow vulnerability has been reported in the Microsoft Windows Server Message Block (SMB) implementation. The SMB Protocol is a network file sharing protocol that is implemented in Microsoft Windows. A remote attacker may exploit this vulnerability to create a denial of service condition or take complete control of a vulnerable system.

Update/Patch Available
Apply patches:
Microsoft Security Bulletin MS11-019

Vulnerability Details
The vulnerability is due to a heap overflow error in the "BowserWriteErrorLogEntry()" function within the Windows NT SMB Minirdr "mrxsmb.sys" driver when processing malformed Browser Election requests. A remote attacker could exploit this flaw by constructing a specially crafted Browser Election request and sending it to a target server. Successful exploitation of this vulnerability could cause the affected system to crash and might result in arbitrary code execution with elevated privileges.

Protection Overview
This protection will detect and block Browser Election requests attempting to exploit this vulnerability.

In order for the protection to be activated, update your Security Gateway/VPN-1 product to the latest IPS/SmartDefense update. For information on how to update IPS/SmartDefense, go to SBP-2006-05, Protection tab and select the version of your choice.

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 > Microsoft Networks.
2. In the right pane, double-click the following protection:

Microsoft Windows SMB mrxsmb.sys Remote Heap Overflow

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: Windows SMB Protection Violation
Attack Information: Microsoft Windows SMB mrxsmb.sys remote heap overflow

Security Gateway: R70/R71

How Can I Protect My Network?
1. In the IPS tab, click Protections > By Protocol > Application Intelligence > Microsoft Networks.
2. In the right pane, double-click the following protection:

Microsoft Windows SMB mrxsmb.sys Remote Heap Overflow

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.

VPN-1 NGX R65 & VSX NGX R65

How Can I Protect My Network?
1. In the SmartDefense tab, click Application Intelligence > Microsoft Networks > Microsoft Windows SMB mrxsmb.sys Remote Heap Overflow.
2. In the configuration pane, under Settings > Mode, check Active.
3. Install policy on all modules.

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 Network Security > SMB, and select the NetBIOS UDP protection group.
3. Click Microsoft Windows SMB mrxsmb.sys Remote Heap Overflow (IPS-1 NGX R65 only).
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: SMB NetBIOS Datagram
Description: Microsoft Windows SMB mrxsmb.sys Remote Heap Overflow

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