Vulnerability Alert

Microsoft Windows Server Service Remote Procedure Call Request Handling Code Execution Vulnerability

 
Threat Type:CWE-94: Code Injection
IntelliShield ID:16941
Version:3
First Published:2008 October 23 17:28 GMT
Last Published:2008 October 25 01:54 GMT
Port: 139, 445
CVE:CVE-2008-4250
BugTraq ID:31874
Urgency:Possible use
Credibility:Confirmed
Severity:Heavy Damage
CVSS Base:10.0 CVSS Calculator
CVSS Version 2.0
CVSS Temporal:8.7
 
Version Summary:

Exploit code has been observed publicly to demonstrate the Microsoft Windows Server Service Remote Procedure Call request handling code execution vulnerability.

 
 
Description

Microsoft Windows contains a buffer overflow vulnerability that could allow an unauthenticated, remote attacker to create a denial of service (DoS) condition or execute arbitrary code.

The vulnerability is due to insufficient boundary checking in the Server service.? An attacker could exploit the vulnerability by sending an remote procedure call (RPC) request designed to trigger an error condition.? As a result of this error, an attacker could create a DoS condition or execute arbitrary code with the elevated privileges of the Server service.

Exploit code is publicly available.

Microsoft has confirmed the vulnerability and released software updates.

 
Warning Indicators

The following versions of Windows are vulnerable:

  • Windows 2000 SP4 and prior
  • Windows XP SP3 and prior
  • Windows XP Professional x64 Edition SP2 and prior
  • Windows Server 2003 SP2 and prior
  • Windows Server 2003 x64 Edition SP2 and prior
  • Windows Server 2003 with SP2 and prior for Itanium-based Systems
  • Windows Vista SP1 and prior
  • Windows Vista x64 Edition SP1 and prior
  • Windows Server 2008 for 32-bit Systems
  • Windows Server 2008 for x64-based Systems
  • Windows Server 2008 for Itanium-based Systems
 
IntelliShield Analysis

Exploits of this vulnerability do not require any?user interaction.? The systems most at risk?for exploit are workstations and servers that allow access to Server services through host-based firewalls.? All systems hold the same risk, regardless of the affected operating system,?as the Server service on each affected version runs with SYSTEM privileges.

An unauthenticated, remote attacker could exploit this vulnerability on Windows 2000, Windows XP, and Windows Server 2003 systems to execute arbitrary code.? Microsoft rates this vulnerability as critical on these systems.? However, on Windows Vista and Windows Server 2008, the rating is important because the attacker must have authenticated access to the targeted network, reducing the likelihood of attacks on these systems. ??

Default configurations of Windows XP SP2/SP3, Windows Vista, and Windows Server 2008 protect the RPC interface with the Windows Firewall.? However, if the Windows Firewall is disabled, or if file or printer sharing has been enabled, the system will still be vulnerable to an attack.

The compromise of a Windows Server system fulfilling the role of an Active Directory domain controller could allow an attacker to gain access to the stored credentials of user accounts within the domain.? If an attacker could retrieve and decrypt those credentials, the attacker could gain access to other resources within the affected site.

Exploit code is publicly available, and the Troj/Gimmiv-A worm is also actively exploiting this vulnerability to install itself on target systems.? Additional information on the worm is available in IntelliShield Alert 16947.

Microsoft corrects this vulnerability by improving the way the Server service handles RPC requests.

The Cisco Applied Intelligence team has re-released the following companion document to guide administrators in identifying and mitigating attempts to exploit this vulnerability prior to applying updated software: Cisco Applied Mitigation Bulletin: Out-of-Band Microsoft Security Bulletin for October 23, 2008

 
Vendor Announcements

Microsoft has released a security bulletin at the following link: MS08-067

US-CERT has released a vulnerability note at the following link: VU#827267

 
Impact

An unauthenticated, remote attacker could exploit this vulnerability to cause a DoS condition or execute arbitrary code with privileges of the Server service.? Because this service runs under the Local System account, an exploit could allow the attacker to gain complete control over the affected system.?

The compromise of an Active Directory domain controller could allow the attacker to gain access to encrypted user credential information that, if decrypted, could allow the attacker to gain access to other computers or resources within the compromised domain.

 
Technical Information

This vulnerability exists due to insufficient validation of input by netapi32.dll of the Server service.? This service provides remote computers access to file and print services and is responsible for named pipes and other communication channels to support?RPC.?

An unauthenticated, remote attacker could exploit the vulnerability by submitting a specially crafted RPC request to the affected service.? This action could trigger an error condition that could allow the attacker to execute arbitrary code with the?Local System privileges of the Server service.

 
Safeguards

Administrators are advised to apply the?appropriate updates.

Administrators may consider disabling the Server and Computer Browser services to prevent this vulnerability from being exploited remotely.? However, the disabling of the service may greatly reduce the functionality of affected systems, preventing the use of many remote network services.

On Windows Vista and Windows Server 2008, administrators are advised to block all RPC requests with the Universally Unique Identifier (UUID) equal to 4b324fc8-1670-01d3-1278-5a47bf6ee188.? Administrators can filter the RPC UUID via the network shell.? Details on the specific commands used are in the bulletin.

Administrators may consider blocking TCP ports 139 and 445 at the firewall; however, this may cause the applications using these ports to not function properly.? A list of applications using these affected ports is available in the bulletin.

Administrators are advised to protect affected systems from external attacks using a solid firewall strategy.

As a temporary workaround, administrators may consider modifying ACLs for named pipes that are associated with the RPC interface.? These ACLs will revert to their default settings each time Windows restarts.

Administrators are advised to restrict access to affected systems.

Administrators are advised to monitor critical systems.

Administrators are advised to employ and update anti-virus applications to prevent malicious software that may attempt to exploit this vulnerability.

Administrators are advised to employ host-based intrusion prevention software to prevent network connections that are established in attempts to exploit this vulnerability.

 
Patches/Software

Microsoft has released updated software at the following links:


Signatures
 
Cisco Intrusion Prevention System (IPS) 6.0
Signature IDSignature NameReleaseLatest Release Date
7280/0Windows Server Service Remote Code ExecutionS5422011 Jan 25 
7280/1Windows Server Service Remote Code ExecutionS6202012 Jan 19 
 
Alert History
 

Version 2, October 23, 2008, 3:51 PM: Microsoft has released additional technical details to describe the remote procedure call request handling code execution vulnerability in the Microsoft Windows Server service.? Cisco has released an applied mitigation bulletin.

Version 1, October 23, 2008, 1:28 PM: Microsoft Windows contains a vulnerability in the Server service that could allow an unauthenticated, remote attacker to create a denial of service condition or execute arbitrary code.? Updates are available.



Product Sets
 
The security vulnerability applies to the following combinations of products.

Primary Products:
Microsoft, Inc.Windows 2000 Advanced Server Base, SP1, SP2, SP3, SP4 | Professional Base, SP1, SP2, SP3, SP4 | Server Base, SP1, SP2, SP3, SP4
Microsoft, Inc.Windows Server 2003 Datacenter Edition Base, SP1, SP2 | Datacenter Edition, 64-bit (Itanium) Base, SP1, SP2 | Datacenter Edition x64 (AMD/EM64T) Base, SP2 | Enterprise Edition Base, SP1, SP2 | Enterprise Edition, 64-bit (Itanium) Base, SP1, SP2 | Enterprise Edition x64 (AMD/EM64T) Base, SP2 | Standard Edition Base, SP1, SP2 | Standard Edition, 64-bit (Itanium) Base, SP1, SP2 | Standard Edition x64 (AMD/EM64T) Base, SP2 | Web Edition Base, SP1, SP2
Microsoft, Inc.Windows Server 2008 Datacenter Edition Base | Datacenter Edition, 64-bit Base | Itanium-Based Systems Edition Base | Enterprise Edition Base | Enterprise Edition, 64-bit Base | Standard Edition Base | Standard Edition, 64-bit Base | Web Server Base | Web Server, 64-bit Base
Microsoft, Inc.Windows Vista Home Basic Base, SP1 | Home Premium Base, SP1 | Business Base, SP1 | Enterprise Base, SP1 | Ultimate Base, SP1 | Home Basic x64 Edition Base, SP1 | Home Premium x64 Edition Base, SP1 | Business x64 Edition Base, SP1 | Enterprise x64 Edition Base, SP1 | Ultimate x64 Edition Base, SP1
Microsoft, Inc.Windows XP Home Edition Base, SP1, SP2, SP3 | Professional Edition Base, SP1, SP2, SP3 | Professional x64 (AMD/EM64T) Base, SP2

Associated Products:
N/A




Alerts and bulletins on the Cisco Security Intelligence Operations Portal are highlighted by analysts in the Cisco Threat Operations Center and represent a subset of the comprehensive content that is available through Cisco Security IntelliShield Alert Manager Service. This customizable threat and vulnerability alert service provides security staff with access to timely, accurate, and credible information about threats and vulnerabilities that may affect their environment.


LEGAL DISCLAIMER
The urgency and severity ratings of this alert are not tailored to individual users; users may value alerts differently based upon their network configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME.
Powered by  IntelliShield