The following security advisory is sent to the securiteam mailing list, and can
be found at the SecuriTeam web site: http://www.securiteam.com
- - promotion
The SecuriTeam alerts list - Free, Accurate, Independent.
Get your security news from a reliable source.
http://www.securiteam.com/mailinglist.html
- - - - - - - - -
Vulnerability in Server Service Allows Denial of Service (MS06-063)
------------------------------------------------------------------------
SUMMARY
Two security vulnerabilities have been discovered in the Server service
allowing a remote attacker to cause the service to no longer respond.
DETAILS
Affected Software:
* Microsoft Windows 2000 Service Pack 4 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=2998105d-6796-4e60-8c9c-e8241385f2a9>
Download the update
* Microsoft Windows XP Service Pack 1 and Microsoft Windows XP Service
Pack 2 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=08ab17b9-149c-44d4-96cf-87a8c6b9dc22>
Download the update
* Microsoft Windows XP Professional x64 Edition -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=433fd0f9-938f-432d-99d4-f41b92235dcf>
Download the update
* Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service
Pack 1 -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=abad4cc1-4ea6-4051-bc5a-79deb4dbe72b>
Download the update
* Microsoft Windows Server 2003 for Itanium-based Systems and Microsoft
Windows Server 2003 with SP1 for Itanium-based Systems -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=849eedef-332b-4792-b84e-3750d407a86f>
Download the update
* Microsoft Windows Server 2003 x64 Edition -
<http://www.microsoft.com/downloads/details.aspx?FamilyId=31e448f7-298d-417c-a857-1646689e0817>
Download the update
Server Service Denial of Service Vulnerability- CVE-2006-3942:
A denial of service vulnerability exists in the Server service because of
the way it handles certain network messages. An attacker could exploit the
vulnerability by sending a specially crafted network message to a computer
running the Server service. An attacker who successfully exploited this
vulnerability could cause the computer to stop responding.
Mitigating Factors for Server Service Denial of Service Vulnerability -
CVE-2006-3942:
* 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.
Workarounds for Server Service Denial of Service Vulnerability -
CVE-2006-3942:
Microsoft has tested the following workarounds. Although these workarounds
will not correct the underlying vulnerability, they help block known
attack vectors. When a workaround reduces functionality, it is identified
in the following section.
* Block the following at the firewall:
* UDP ports 135, 137, 138, and 445, and TCP ports 135, 139, 445, and 593
* To help protect from network-based attempts to exploit this
vulnerability, use a personal firewall, such as the Internet Connection
Firewall, which is included with Windows XP and with Windows Server 2003.
By default, the Internet Connection Firewall feature in Windows XP and in
Windows Server 2003 helps protect your Internet connection by blocking
unsolicited incoming traffic. We recommend that you block all unsolicited
incoming communication from the Internet. In Windows XP Service Pack 2
this features is called the Windows Firewall.
To enable the Internet Connection Firewall feature by using the Network
Setup Wizard, follow these steps:
1. Click Start, and then click Control Panel.
2. In the default Category View, click Network and Internet Connections,
and then click Setup or change your home or small office network. The
Internet Connection Firewall feature is enabled when you select a
configuration in the Network Setup Wizard that indicates that your system
is connected directly to the Internet.
To configure Internet Connection Firewall manually for a connection,
follow these steps:
1. Click Start, and then click Control Panel.
2. In the default Category View, click Networking and Internet
Connections, and then click Network Connections.
3. Right-click the connection on which you want to enable Internet
Connection Firewall, and then click Properties.
4. Click the Advanced tab.
5. Click to select the Protect my computer or network by limiting or
preventing access to this computer from the Internet check box, and then
click OK.
Note If you want to enable certain programs and services to communicate
through the firewall, click Settings on the Advanced tab, and then select
the programs, the protocols, and the services that are required.
* To help protect from network-based attempts to exploit this
vulnerability, block the affected ports by using IPSec on the affected
systems.
Use Internet Protocol security (IPSec) to help protect network
communications. Detailed information about IPSec and about how to apply
filters is available in Microsoft Knowledge Base Article
<http://support.microsoft.com/kb/313190> 313190 and Microsoft Knowledge
Base Article <http://support.microsoft.com/kb/813878> 813878
FAQ for Server Service Denial of Service Vulnerability - CVE-2006-3942:
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. During that time, the server would be unable to
respond to requests. 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?
An uninitialized buffer in the Server service.
What is the Server service?
The Server service provides remote procedure cal (RPC) support, file and
print support and named pipe sharing over the network. The Server service
allows the sharing of your local resources (such as disks and printers) so
that other users on the network can access them. It also allows named pipe
communication between applications running on other computers and your
computer.
Who could exploit the vulnerability?
Any anonymous user who could deliver a specially crafted message to the
affected system could try to exploit this vulnerability.
How could an attacker exploit the vulnerability?
An attacker could try to exploit the vulnerability by creating a specially
crafted message and sending the message to an affected system. The message
could then cause the affected system to stop responding.
What systems are primarily at risk from the vulnerability?
All Windows computers are equally at risk from this vulnerability.
Could the vulnerability be exploited over the Internet?
Yes. An attacker could try to exploit this vulnerability over the
Internet. Firewall best practices and standard default firewall
configurations can help protect against attacks that originate from the
Internet. Microsoft has provided information about how you can help
protect your PC. End users can visit the Protect Your PC Web site. IT
professionals can visit the Security Guidance Center Web site.
What does the update do?
The update removes the vulnerability by initializing a buffer before it is
used.
When this security bulletin was issued, had this vulnerability been
publicly disclosed?
Yes. This vulnerability has been publicly disclosed. It has been assigned
Common Vulnerability and Exposure number CVE-2006-3942. It also has been
named Mailslot DOS by the larger security community
When this security bulletin was issued, had Microsoft received any reports
that this vulnerability was being exploited?
No. Microsoft had seen examples of proof of concept code published
publicly but had not received any information to indicate that this
vulnerability had been publicly used to attack customers when this
security bulletin was originally issued.
Does applying this security update help protect customers from the code
that has been published publicly that attempts to exploit this
vulnerability?
Yes. This security update addresses the vulnerability that potentially
could be exploited by using the published proof of concept code. The
vulnerability that has been addressed has been assigned the Common
Vulnerability and Exposure number CVE-2006-3942.
How does this vulnerability relate to the vulnerabilities that are
corrected by MS06-035 and MS06-040?
All three vulnerabilities were in the Server service. However, this update
addresses a new vulnerability that was not addressed as part of MS06-035
or as part of MS06-040. MS06-035 and MS06-040 help protect against the
vulnerabilities that were discussed in those bulletins, but do not address
this new vulnerability. This update does not replace MS06-040. You must
install this update and the update that is provided as part of the
MS06-040 security bulletin to help protect your system against both
vulnerabilities. This bulletin does replace MS06-035. Installing this
update will protect against all vulnerabilities fixed in MS06-035.
SMB Rename Vulnerability - CVE-2006-4696:
A remote code execution vulnerability exists in the Server service because
of the way it handles certain network messages. An attacker could exploit
the vulnerability sending a specially crafted network message to a
computer running the Server service as an authenticated user. An attacker
who successfully exploited this vulnerability could take complete control
of the affected system.
Mitigating Factors for SMB Rename Vulnerability - CVE-2006-4696:
* 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.
* An attacker must have valid logon credentials and be able to log on
over the network to exploit this vulnerability. The vulnerability could
not be exploited by anonymous users.
Workarounds for SMB Rename Vulnerability - CVE-2006-4696:
Microsoft has tested the following workarounds. Although these workarounds
will not correct the underlying vulnerability, they help block known
attack vectors. When a workaround reduces functionality, it is identified
in the following section.
* Block the following at the firewall:
* UDP ports 135, 137, 138, and 445, and TCP ports 135, 139, 445, and 593
* To help protect from network-based attempts to exploit this
vulnerability, use a personal firewall, such as the Internet Connection
Firewall, which is included with Windows XP and with Windows Server 2003.
By default, the Internet Connection Firewall feature in Windows XP and in
Windows Server 2003 helps protect your Internet connection by blocking
unsolicited incoming traffic. We recommend that you block all unsolicited
incoming communication from the Internet. In Windows XP Service Pack 2
this features is called the Windows Firewall.
To enable the Internet Connection Firewall feature by using the Network
Setup Wizard, follow these steps:
1. Click Start, and then click Control Panel.
2. In the default Category View, click Network and Internet Connections,
and then click Setup or change your home or small office network. The
Internet Connection Firewall feature is enabled when you select a
configuration in the Network Setup Wizard that indicates that your system
is connected directly to the Internet.
To configure Internet Connection Firewall manually for a connection,
follow these steps:
1. Click Start, and then click Control Panel.
2. In the default Category View, click Networking and Internet
Connections, and then click Network Connections.
3. Right-click the connection on which you want to enable Internet
Connection Firewall, and then click Properties.
4. Click the Advanced tab.
5. Click to select the Protect my computer or network by limiting or
preventing access to this computer from the Internet check box, and then
click OK.
Note If you want to enable certain programs and services to communicate
through the firewall, click Settings on the Advanced tab, and then select
the programs, the protocols, and the services that are required.
* To help protect from network-based attempts to exploit this
vulnerability, block the affected ports by using IPSec on the affected
systems.
Use Internet Protocol security (IPSec) to help protect network
communications. Detailed information about IPSec and about how to apply
filters is available in Microsoft Knowledge Base Article
<http://support.microsoft.com/kb/313190> 313190 and Microsoft Knowledge
Base Article <http://support.microsoft.com/kb/813878> 813878.
FAQ for SMB Rename Vulnerability - CVE-2006-4696:
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who exploited
this vulnerability could take complete control of an affected system.
What causes the vulnerability?
The vulnerability is caused by the Server service attempting to
dereference an invalid pointer.
What is the Server service?
The Server service provides RPC support, file and print support and named
pipe sharing over the network. The Server service allows the sharing of
your local resources (such as disks and printers) so that other users on
the network can access them. It also allows named pipe communication
between applications running on other computers and your computer, which
is used for RPC.
Who could exploit the vulnerability?
Any authenticated user who could deliver a specially crafted message to
the affected system could try to exploit this vulnerability.
How could an attacker exploit the vulnerability?
An attacker could try to exploit the vulnerability by creating a specially
crafted message and sending the message to an affected system.
What systems are primarily at risk from the vulnerability?
All Windows computers are equally at risk from this vulnerability.
Could the vulnerability be exploited over the Internet?
Yes. An attacker could try to exploit this vulnerability over the
Internet. Firewall best practices and standard default firewall
configurations can help protect against attacks that originate from the
Internet. Microsoft has provided information about how you can help
protect your PC. End users can visit the Protect Your PC Web site. IT
professionals can visit the Security Guidance Center Web site.
What does the update do?
The update removes the vulnerability by removing the faulty code.
When this security bulletin was issued, had this vulnerability been
publicly disclosed?
No. Microsoft received information about this vulnerability through
responsible disclosure. Microsoft had not received any information to
indicate that this vulnerability had been publicly disclosed when this
security bulletin was originally issued.
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.
How does this vulnerability relate to the vulnerabilities that are
corrected by MS06-035 and MS06-040?
All three vulnerabilities were in the Server service. However, this update
addresses a new vulnerability that was not addressed as part of MS06-035
or as part of MS06-040. MS06-035 and MS06-040 help protect against the
vulnerabilities that were discussed in those bulletins, but do not address
this new vulnerability. This update does not replace MS06-040. You must
install this update and the update that is provided as part of the
MS06-040 security bulletin to help protect your system against both
vulnerabilities. This bulletin does replace MS06-035. Installation of this
update will protect against the vulnerabilities addressed in MS06-035.
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/MS06-063.mspx>
http://www.microsoft.com/technet/security/Bulletin/MS06-063.mspx
========================================
This bulletin is sent to members of the SecuriTeam mailing list.
To unsubscribe from the list, send mail with an empty subject line and body to:
list-unsubscribe@securiteam.com
In order to subscribe to the mailing list, simply forward this email to:
list-subscribe@securiteam.com
====================
====================
DISCLAIMER:
The information in this bulletin is provided "AS IS" without warranty of any
kind.
In no event shall we be liable for any damages whatsoever including direct,
indirect, incidental, consequential, loss of business profits or special
damages.
