Microsoft Windows contains a vulnerability in the DNS server component that could allow an unauthenticated, remote attacker to insert entries into the DNS cache. Updates are available.
Microsoft Windows and Windows Server contain a vulnerability in the DNS server component that could allow an unauthenticated, remote attacker to insert entries into the DNS cache.
This vulnerability is due to errors when processing repeated malicious queries. An unauthenticated, remote attacker could exploit this vulnerability by sending a series of DNS requests to the server. If successful, the attacker could gather information that could allow the attacker to insert arbitrary entries into the system's DNS cache.
Microsoft has confirmed this vulnerability and released software updates.
The following Microsoft Windows-based systems running DNS services are affected:
Windows 2000 Server SP4
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 Server 2008 for 32-bit Systems
Windows Server 2008 for x64-based Systems
Exploits targeting this vulnerability are likely to be part of a multistage spoofing or phishing attack. An attacker may first identify a caching DNS server in use by a targeted organization or site. By inserting entries into that DNS cache, the attacker could conduct a man-in-the-middle attack against client systems that rely on the DNS server. The attacker could redirect client traffic from legitimate sites to malicious sites, possibly in an attempt to steal sensitive information from financial websites or in an effort to install malicious software on end-user host systems.
The update available from Microsoft corrects this vulnerability by correcting the processing of malformed queries.
Microsoft has released a security bulletin at the following link: MS09-008
An unauthenticated, remote attacker could exploit this vulnerability to insert arbitrary DNS records into the cache of affected servers, possibly allowing the attacker to conduct spoofing or man-in-the-middle attacks against hosts that depend on the vulnerable DNS host.
This vulnerability is due to errors when processing repeated malicious queries. The DNS server does not reuse responses to repeated DNS lookups, allowing an attacker to potentially predict future transaction IDs. An unauthenticated, remote attacker could exploit this vulnerability by determining transaction IDs and sending a malicious request to the server. The processing of the request could cause the server to store the request in the cache, allowing the attacker to insert arbitrary entries into the DNS cache.
Administrators are advised to apply the appropriate updates.
Administrators are advised to restrict access to trusted users.
Administrators may consider employing network filtering devices to block malformed requests to vulnerable systems.
Microsoft customers can obtain updates directly by using the links in the MS09-008 security bulletin. These updates are also distributed by Windows automatic update features and available on the Windows Update website. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
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