Executive Summary

Title Microsoft Windows browser election message kernel pool overflow
Name VU#323172 First vendor Publication 2011-02-16
Vendor VU-CERT Last vendor Modification 2011-04-15
Severity (Vendor) N/A Revision M

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score NA
Base Score NA Environmental Score NA
impact SubScore NA Temporal Score NA
Exploitabality Sub Score NA
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector : (AV:N/AC:L/Au:N/C:C/I:C/A:C)
Cvss Base Score 10 Attack Range Network
Cvss Impact Score 10 Attack Complexity Low
Cvss Expoit Score 10 Authentication None Required
Calculate full CVSS 2.0 Vectors scores


Vulnerability Note VU#323172

Microsoft Windows browser election message kernel pool overflow


A vulnerability exists in the way the Microsoft Windows browser service handles Browser Election messages.

I. Description

From Description of the Microsoft Computer Browser Service:

"The browser service maintains a list of the domain name or workgroup name the computer is in, and the protocol being used for each computer on the network segment being served by the computer running the browser service. On each network segment, a master browser is elected from the group of computers located on the segment that are running the browser service."

The computer browser service protocol driver contains an integer underflow error in browser election message handling, which can cause a kernel pool buffer overrun resulting in memory corruption.

The vulnerable code is only reached if the computer is the Master Browser. However, according to the Microsoft Security Research and Defense blog, the election of the Master Browser varies depending on network configuration:

"In normal enterprise networks the Primary Domain Controller (PDC) will become Master Browser, but depending on the network configuration, other computers on the network can become Master Browser, and therefore be vulnerable. A single system will be Master Browser at any point in time."

For more information, please see Microsoft Security Bulletin MS11-019.

II. Impact

Using a specially crafted Browser Election message, an attacker may be able to cause a Denial of Service (DoS) or execute arbitrary code.

III. Solution

Apply an update

Microsoft addresses this vulnerability with the updates listed in Microsoft Security Bulletin MS11-19.

Restrict Access

Restrict access to the server's broadcast domain and block UDP ports 137, 138 and TCP ports 139, 445 at the network perimeter using firewall rules.

Vendor Information

VendorStatusDate NotifiedDate Updated
Microsoft CorporationAffected2011-04-15




This document was written by David Warren.

Other Information

Date Public:2011-02-14
Date First Published:2011-02-16
Date Last Updated:2011-04-15
CERT Advisory: 
US-CERT Technical Alerts: 
Severity Metric:18.73
Document Revision:17

Original Source

Url : http://www.kb.cert.org/vuls/id/323172

CWE : Common Weakness Enumeration

% Id Name
100 % CWE-119 Failure to Constrain Operations within the Bounds of a Memory Buffer

OVAL Definitions

Definition Id: oval:org.mitre.oval:def:12637
Oval ID: oval:org.mitre.oval:def:12637
Title: Browser Pool Corruption Vulnerability
Description: Integer underflow in the BowserWriteErrorLogEntry function in the Common Internet File System (CIFS) browser service in Mrxsmb.sys or bowser.sys in Active Directory in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 allows remote attackers to execute arbitrary code or cause a denial of service (system crash) via a malformed BROWSER ELECTION message, leading to a heap-based buffer overflow, aka "Browser Pool Corruption Vulnerability." NOTE: some of these details are obtained from third party information.
Family: windows Class: vulnerability
Reference(s): CVE-2011-0654
Version: 8
Platform(s): Microsoft Windows XP
Microsoft Windows Server 2003
Microsoft Windows Vista
Microsoft Windows 7
Microsoft Windows Server 2008
Microsoft Windows Server 2008 R2
Definition Synopsis:

CPE : Common Platform Enumeration

Os 4
Os 2

OpenVAS Exploits

Date Description
2011-04-13 Name : Microsoft SMB Client Remote Code Execution Vulnerabilities (2511455)
File : nvt/secpod_ms11-019.nasl
2011-02-18 Name : Microsoft Windows2k3 Active Directory 'BROWSER ELECTION' Buffer Overflow Vuln...
File : nvt/gb_ms_windows2k3_active_directory_bof_vuln.nasl

Open Source Vulnerability Database (OSVDB)

Id Description
71773 Microsoft Windows Common Internet File System (CIFS) Malformed Browser Messag...

Microsoft Windows is prone to an overflow condition. The 'BowserWriteErrorLogEntry' function in the CIFS browser service in 'Mrxsmb.sys' or 'bowser.sys' in Active Directory fails to properly sanitize user-supplied input resulting in a heap-based buffer overflow. With a specially crafted BROWSER ELECTION message, a remote attacker can potentially execute arbitrary code.

Snort® IPS/IDS

Date Description
2014-01-10 Microsoft Windows 2003 browser election remote heap overflow attempt
RuleID : 18994 - Revision : 8 - Type : OS-WINDOWS
2015-05-28 Common Internet File System Browser Protocol BowserWriteErrorLogEntry
RuleID : 18653 - Revision : 4 - Type : NETBIOS
2014-01-10 Microsoft Windows 2003 browser election remote heap overflow attempt
RuleID : 18462 - Revision : 10 - Type : OS-WINDOWS

Nessus® Vulnerability Scanner

Date Description
2011-04-13 Name : Arbitrary code can be executed on the remote host through the installed SMB c...
File : smb_nt_ms11-019.nasl - Type : ACT_GATHER_INFO

Alert History

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Date Informations
2015-05-08 13:28:01
  • Multiple Updates
2013-05-11 00:57:01
  • Multiple Updates