Microsoft Security Bulletin MS08-065 - Important

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

• By default, the Message Queuing component is not installed on any affected operating system edition and can only be enabled by a user with administrative privileges. Only customers who manually install the Message Queuing component are likely to be vulnerable to this issue.
• For customers that require the Message Queuing component, firewall best practices and standard default firewall configurations can help protect networks from attacks that originate outside the enterprise perimeter. Best practices recommend that systems that are connected to the Internet have a minimal number of ports exposed.

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

• Block the following at the perimeter firewall
  • All unsolicited inbound traffic on ports greater than 1024
  • Any other specifically configured RPC port
    
    These ports are used to initiate a connection with RPC. Blocking them at the firewall will help prevent systems that are behind that firewall from attempts to exploit this vulnerability. Also, make sure that you block any other specifically configured RPC port on the remote system. Microsoft recommends that you block all unsolicited inbound communication from the Internet to help prevent attacks that may use other ports. For more information about the ports that RPC uses, visit TCP and UDP Port Assignments.
• Disable the Message Queuing Service:
  • Interactively
    
    Disabling the Message Queuing service will help protect the affected system from attempts to exploit this vulnerability. To disable the Message Queuing service, follow these steps:
    
    1. Click Start, and then click Control Panel. Alternatively, point to Settings, and then click Control Panel.
    
    2. Double-click Administrative Tools. Alternatively, click Switch to Classic View and then double-click Administrative Tools.
    
    3. Double-click Services.
    
    4. Double-click Message Queuing.
    
    5. In the Startup type list, click Disabled.
    
    6. Click Stop, and then click OK.
  • By Group Policy:
    
    Disable the Message Queuing service by using the Group Policy settings. You can disable the startup of this service at either the local, site, domain, or organizational-unit level by using Group Policy object functionality in Microsoft Windows 2000 domain environments or in Windows Server 2003 domain environments.
    
    Note: You may also review the Windows Server 2003 Security Guide. This guide includes information about how to disable services.
    For more information about Group Policy, visit the following Microsoft Web site:
    
    Step-by-Step Guide to Understanding the Group Policy Feature Set

  You can also stop and disable the MSMQ service by using the following command at the command prompt (available in Windows XP and in the Microsoft Windows 2000 Resource Kit):

  Sc stop MSMQ & sc config MSMQ start= disabled

  How to undo the workaround: Use the steps above to set the Startup Type to Automatic and start the service.

What is the scope of the vulnerability? 
This is a remote code execution vulnerability for Microsoft Windows 2000 systems with the MSMQ service enabled. An attacker who successfully exploited this vulnerability could take complete control of an affected system remotely. An attacker could then install programs or view, change, or delete data.

What causes the vulnerability? 
The MSMQ service does not correctly parse specifically crafted RPC requests.

What is Message Queuing? 
Microsoft Message Queuing technology enables applications that are running at different times to communicate across heterogeneous networks and across systems that may be temporarily offline. Applications send messages to queues and read messages from queues. Message Queuing provides guaranteed message delivery, efficient routing, security, and priority-based messaging. It can be used to implement solutions for both asynchronous and synchronous messaging scenarios. For more information about Message Queuing, see the Message Queuing product documentation.

What is RPC? 
Microsoft RPC is a model for programming in a distributed computing environment. The goal of RPC is to provide transparent communication so that the client appears to be directly communicating with the server. Microsoft's implementation of RPC is compatible with the Open Software Foundation (OSF) Distributed Computing Environment (DCE) RPC. For more information about RPC, see the RPC MSDN site.

What might an attacker use the vulnerability to do? 
An unauthenticated attacker could cause arbitrary code to run remotely in the context of SYSTEM by sending a specially crafted RPC request to the MSMQ service. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability? 
An attacker could exploit this vulnerability by sending a specially crafted RPC request to the MSMQ service. A heap request can be controlled and later overflowed during an unchecked string copy operation. Successful exploitation of this vulnerability could lead to full access of the affected system under the SYSTEM context.

What systems are primarily at risk from the vulnerability? 
Microsoft Windows 2000 systems with the MSMQ service enabled are the systems that are at risk.

What does the update do? 
The update removes the vulnerability by modifying the way that the MSMQ service validates parameters to the string APIs invoked by MSMQ.

When this security bulletin was issued, had this vulnerability been publicly disclosed? 
No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited? 
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.

Reference Table

The following table contains the security update information for this software. You can find additional information in the subsection, Deployment Information, in this section.