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Credit:
The information has been provided by Microsoft Product Security.
The original article can be found at: http://www.microsoft.com/technet/security/bulletin/ms08-004.mspx
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Affected Software
Operating System - Maximum Security Impact - Aggregate Severity Rating - Bulletins Replaced by this Update
* Windows Vista - Denial of Service - Important - MS08-001
* Windows Vista x64 Edition - Denial of Service - Important - MS08-001
Non-Affected Software
* Microsoft Windows 2000 Service Pack 4
* Windows XP Service Pack 2
* Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2
* Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2
* Windows Server 2003 x64 Edition and Windows 2003 Server x64 Edition Service Pack 2
* Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium based Systems
* Windows Vista Service Pack 1 (all editions)
* Windows Server 2008 (all editions)
Windows Vista TCP/IP Vulnerability - CVE-2008-0084
A denial of service vulnerability exists in TCP/IP processing in Windows Vista. An attacker could exploit the vulnerability by creating a specially crafted DHCP server that returns a specially crafted packet to a host, corrupting TCP/IP structures and causing the affected system to stop responding and automatically restart.
CVE Information:
CVE-2008-0084
Mitigating Factors for Windows Vista TCP/IP Vulnerability - CVE-2008-0084
Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of vulnerability. The following mitigating factors may be helpful in your situation:
* An attacker can only receive a DHCP request and respond with a specially crafted packet by using a specially crafted DHCP server within the same link or via a DHCP Relay Agent.
Workarounds for Windows Vista TCP/IP Vulnerability - CVE-2008-0084
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:
* Assign a static IP address to the client computer instead of allowing the client computer to automatically request an IP address. Perform the following steps:
1. On the client computer, click Control Panel, then click Network and Sharing Center.
2. Local Area Connection and click View Status.
3. Click Properties.
4. Click Internet Protocol Version 4 (TCP/IPv4) and click Properties.
5. Select Use the following IP address and enter the values in IP address, Subnet mask, Default gateway, and Preferred DNS server.
6. Click OK.
Impact of workaround Automatic requests for an IP address have been bypassed.
How to undo the workaround. Re-enable automatic requests for an IP address by performing the following steps:
1. On the client computer, click Control Panel, then click Network and Sharing Center or Network Connections.
2. Local Area Connection and click View Status.
3. Click Properties.
4. Click Internet Protocol Version 4 (TCP/IPv4) click Properties.
5. Select Obtain an IP address automatically.
6. Click OK.
FAQ for Windows Vista TCP/IP Vulnerability - CVE-2008-0084
What is the scope of the vulnerability?
This is a denial of service vulnerability. An attacker who exploited this vulnerability could cause the affected system to stop responding and automatically restart. Note that the denial of service vulnerability would not allow an attacker to execute code or to elevate their user rights, but it could cause the affected system to stop accepting requests.
What causes the vulnerability?
The vulnerability lies in the way that the TCP/IP stack handles packets received from DHCP servers.
What is DHCP?
Dynamic Host Configuration Protocol (DHCP) is a protocol used by networked devices (hosts) to obtain various parameters necessary for the hosts to operate in an Internet Protocol (IP) network. By using this protocol, system administration workload greatly decreases, and devices can be added to the network with minimal or no manual configurations. A DHCP server assigns IP addresses to host computers.
What is TCP/IP? Is TCP/IP vulnerable?
TCP/IP is the suite of communications protocols used for transmitting data over networks. The current version of TCP/IP is TCP/IPv4, which is vulnerable (see also the Workarounds section of this vulnerability entry). The next version, TCP/IPv6, is not affected by this vulnerability.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could cause an affected system to become non-responsive and automatically restart.
How could an attacker exploit the vulnerability?
An attacker could exploit the vulnerability by creating a specially crafted DHCP server that returns a specially crafted packet to a host, corrupting TCP/IP structures and causing the affected system to stop responding and automatically restart.
What systems are primarily at risk from the vulnerability?
Windows Vista clients that request an IP address from the DHCP server are primarily at risk.
What does the update do?
The update removes the vulnerability by adding more validation to the way that the TCP/IP stack handles packets received from DHCP servers.
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.
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