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Vulnerability in DNS Client Allows Spoofing (MS08-020)
------------------------------------------------------------------------
SUMMARY
This security update resolves a privately reported vulnerability. This
spoofing vulnerability exists in Windows DNS clients and could allow an
attacker to send specially crafted responses to DNS requests, thereby
spoofing or redirecting Internet traffic from legitimate locations.
This is an important security update for Windows Vista and all supported
editions of Microsoft Windows 2000, Windows XP, and Windows Server 2003.
For more information, see the subsection, Affected and Non-Affected
Software, in this section.
DETAILS
Affected Software:
Operating System - Maximum Security Impact - Aggregate Severity Rating -
Bulletins Replaced by This Update
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=41326ade-96b6-47ce-9291-d4e3039471c4>
Microsoft Windows 2000 Service Pack 4 - Spoofing - Important - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyID=893f4cef-0395-4c44-ba28-7a10b6e7dd48>
Windows XP Service Pack 2 - Spoofing - Important - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyID=8fdd1207-6e93-4c43-bacc-fe3623a6ebe7>
Windows XP Professional x64 Edition and Windows XP Professional x64 Edition
Service Pack 2 - Spoofing - Important - None
* W
<http://www.microsoft.com/downloads/details.aspx?FamilyId=214bd8f5-6eb2-414c-b013-c516a306d692>
indows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2 -
Spoofing - Important - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=fd123394-a5d6-4b55-be74-2938f52ce922>
Windows Server 2003 x64 Edition and Windows Server 2003 x64 Edition Service
Pack 2 - Spoofing - Important - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyId=e0e63f03-904d-47ee-94fc-51a8dea668eb>
Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003
with SP2 for Itanium-based Systems - Spoofing - Important - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyID=8203d303-c855-4579-9bbf-b06ddf5c1b87>
Windows Vista - Spoofing - Important - None
*
<http://www.microsoft.com/downloads/details.aspx?FamilyID=73f3a234-3973-4467-be7e-69efa7ee978c>
Windows Vista x64 Edition - Spoofing - Important - None
Non-Affected Software:
* Windows Vista Service Pack 1 (all editions)
* Windows Server 2008 (all editions)
DNS Spoofing Attack Vulnerability - CVE-2008-0087
A spoofing vulnerability exists in Windows DNS clients. The vulnerability
could allow an unauthenticated attacker to send malicious responses to DNS
requests made by vulnerable clients, thereby spoofing or redirecting
Internet traffic from legitimate locations.
CVE Information:
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-0087>
CVE-2008-0087
FAQ for DNS Spoofing Attack Vulnerability - CVE-2008-0087
What is the scope of the vulnerability?
A spoofing vulnerability exists in Windows DNS Clients. An attacker who
successfully exploited this vulnerability could impersonate a legitimate
address.
What causes the vulnerability?
The Windows DNS Client service doesn t provide enough entropy in its
random choice of transaction values when performing DNS queries.
What might an attacker use the vulnerability to do?
An attacker who has successfully gained information about DNS client
transaction IDs could use that information to send malicious responses to
DNS requests.
How could an attacker exploit the vulnerability?
An attacker who successfully exploited this vulnerability could respond to
a DNS query with false or misleading information, thereby redirecting
Internet traffic from legitimate locations to an address of the attacker s
choice.
What is the Domain Name System (DNS)?
Domain Name System (DNS) is one of the industry-standard suite of
protocols that comprise TCP/IP. DNS is implemented using two software
components: the DNS server and the DNS client (or resolver). Both
components are run as background service applications. Network resources
are identified by numeric IP addresses, but these IP addresses are
difficult for network users to remember. The DNS database contains records
that map user-friendly alphanumeric names for network resources to the IP
address used by those resources for communication. In this way, DNS acts
as a mnemonic device, making network resources easier to remember for
network users. For more information and to view logical diagrams
illustrating how DNS fits with other Windows technologies, review the
article How DNS Works.
Could the vulnerability be exploited over the Internet?
Yes, an attacker could exploit this vulnerability over the Internet by
sending specific responses to an Internet-facing client system that is
performing DNS queries.
What systems are primarily at risk from the vulnerability?
Any Windows system that is connected to the Internet or another network
populated by potentially hostile users would be at risk. Windows XP
Service Pack 3, Windows Vista SP1, and Windows Server 2008 are not
affected by this vulnerability.
What does the update do?
The update removes this vulnerability by increasing the randomness of the
transaction IDs in DNS client communications.
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.
ADDITIONAL INFORMATION
The information has been provided by Microsoft Product Security.
The original article can be found at:
<http://www.microsoft.com/technet/security/Bulletin/MS08-020.mspx>
http://www.microsoft.com/technet/security/Bulletin/MS08-020.mspx
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