[NT] Vulnerability in Server Service Could Allow Remote Code Execution (MS06-035)

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Vulnerability in Server Service Could Allow Remote Code Execution
(MS06-035)
------------------------------------------------------------------------


SUMMARY

Improper handling of user input allows attackers to execute arbitrary code
and retrieve information from Server Service.

DETAILS

Vulnerable Systems:
* Microsoft Windows 2000 Service Pack 4
<http://www.microsoft.com/downloads/details.aspx?FamilyId=b207020d-90f7-4c41-8304-06af0ded6467> Download the update
* Microsoft Windows XP Service Pack 1 and Microsoft Windows XP Service
Pack 2
<http://www.microsoft.com/downloads/details.aspx?FamilyId=2592a44c-82fb-4ccd-82a6-fcac7ca33172> Download the update
* Microsoft Windows XP Professional x64 Edition
<http://www.microsoft.com/downloads/details.aspx?FamilyId=b0f67167-7ede-4355-af6f-50c6615f6bbd> Download the update
* Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service
Pack 1
<http://www.microsoft.com/downloads/details.aspx?FamilyId=48f03ad7-38f9-48f4-bbfc-14c52e9c942a> 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=41a4a07f-bea3-48d6-b8d2-d7a5600d7179> Download the update
* Microsoft Windows Server 2003 x64 Edition
<http://www.microsoft.com/downloads/details.aspx?FamilyId=dfbf3fa6-9e11-48b4-894d-5436693d17f7> Download the update

Immune Systems:
* Microsoft Windows 98, Microsoft Windows 98 Second Edition (SE), and
Microsoft Windows Millennium Edition (Me)

Mailslot Heap Overflow Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1314>
CVE-2006-1314:
There is a remote code execution vulnerability in the Server driver that
could allow an attacker who successfully exploited this vulnerability to
take complete control of the affected system.

Mitigating Factors for Mailslot Heap Overflow Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1314>
CVE-2006-1314:
* 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.
* Microsoft Windows XP Service Pack 2 and Microsoft Windows Server 2003
Service Pack 1 do not have services listening on Mailslots in default
configurations.
* Attempts to exploit this vulnerability will most probably result in a
Denial of Service condition caused by an unexpected restart of the
affected system rather than Remote Code Execution.

Workarounds for Mailslot Heap Overflow Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1314>
CVE-2006-1314:
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 TCP port 445 at the firewall:

This port is used to initiate a connection with the affected component.
Blocking TCP port 445 at the firewall will help protect systems that are
behind that firewall from attempts to exploit this vulnerability. We
recommend that you block all unsolicited inbound communication from the
Internet to help prevent attacks that may use other ports. For more
information about ports, visit the following
<http://go.microsoft.com/fwlink/?LinkId=21312> Web site.

* To help protect from network-based attempts to exploit this
vulnerability, use a personal firewall, such as the
<http://go.microsoft.com/fwlink/?LinkId=33335> 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, enable advanced TCP/IP filtering on systems that support
this feature.

You can enable advanced TCP/IP filtering to block all unsolicited inbound
traffic. For more information about how to configure TCP/IP filtering, see
<http://support.microsoft.com/kb/309798> Microsoft Knowledge Base Article
309798.

* 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 <http://support.microsoft.com/kb/313190>
Microsoft Knowledge Base Article 313190 and
<http://support.microsoft.com/kb/813878> Microsoft Knowledge Base Article
813878.

FAQ for Mailslot Heap Overflow Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1314>
CVE-2006-1314:
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who
successfully exploited this vulnerability could remotely take complete
control of an affected system. An attacker could then install programs;
view, change, or delete data; or create new accounts with full user
rights.

What causes the vulnerability?
An unchecked buffer in the Server service.

What is a Mailslot?
A mailslot is a temporary mechanism utilized by applications and processes
to facilitate unidirectional data transfer. For more information about
Mailslots, visit the following
<http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ipc/base/writing_to_a_mailslot.asp> Web site.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could take
complete control of the affected system.

Who could exploit the vulnerability?
Any anonymous user who could deliver a specially crafted network packet 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 and sending
a specially crafted network packet to an affected system. The network
packet could then cause the affected system to execute code.

What systems are primarily at risk from the vulnerability?
Workstations and servers are both 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
<http://go.microsoft.com/fwlink/?LinkId=21169> Protect Your PC Web site.
IT professionals can visit the
<http://go.microsoft.com/fwlink/?LinkId=21171> Security Guidance Center
Web site.

What does the update do?
The update removes the vulnerability by modifying the way that Server
driver validates the length of a message before it passes the message to
the allocated buffer.

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.

SMB Information Disclosure Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1315>
CVE-2006-1315:
There is an information disclosure vulnerability in the Server service
that could allow an attacker to view fragments of memory used to store SMB
traffic during transport.

Mitigating Factors for SMB Information Disclosure Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1315>
CVE-2006-1315:
* 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.

* For customers who require the affected 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.

* On Windows 2000, Windows XP Service Pack 1, and Windows Server 2003, an
attacker must have valid logon credentials to exploit this vulnerability.
The vulnerability could not exploited by anonymous users. However, the
affected component is available remotely to users who have standard user
accounts. In certain configurations, anonymous users could authenticate as
the Guest account. For more information, see Microsoft Security Advisory
906574.

* 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 SMB Information Disclosure Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1315>
CVE-2006-1315:
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.

Note Other protocols such as Internetwork Packet Exchange (IPX) and
Sequenced Packet Exchange (SPX) could be vulnerable to this issue. If
vulnerable protocols such as IPX and SPX are in use, it is important to
block the appropriate ports for those protocols as well. For more
information about IPX and SPX, visit the following Microsoft
<http://www.microsoft.com/resources/documentation/Windows/XP/all/reskit/en-us/prch_cnn_goue.asp> Web site.

* Block TCP ports 139 and 445 at the firewall:

These ports are used to initiate a connection with the affected protocol.
Blocking them at the firewall, both inbound and outbound, will help
prevent systems that are behind that firewall from attempts to exploit
this vulnerability. We recommend that you block all unsolicited inbound
communication from the Internet to help prevent attacks that may use other
ports. For more information about ports, visit the following Web site.

* To help protect from network-based attempts to exploit this
vulnerability, use a personal firewall, such as the
<http://go.microsoft.com/fwlink/?LinkId=33335> 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.

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, enable advanced TCP/IP filtering on systems that support
this feature.

You can enable advanced TCP/IP filtering to block all unsolicited inbound
traffic. For more information about how to configure TCP/IP filtering, see
<http://support.microsoft.com/kb/309798> Microsoft Knowledge Base Article
309798.

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 <http://support.microsoft.com/kb/313190>
Microsoft Knowledge Base Article 313190 and
<http://support.microsoft.com/kb/813878> Microsoft Knowledge Base Article
813878.

FAQ for SMB Information Disclosure Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1315>
CVE-2006-1315:
What is the scope of the vulnerability?
This is an information disclosure vulnerability. An attacker who
successfully exploited this vulnerability could remotely read information
stored in buffers for Server Message Block traffic. Note that this
vulnerability would not allow an attacker to execute code or to elevate
their user rights directly. It could be used to produce useful information
to try to further compromise the affected system.

What causes the vulnerability?
An uninitialized buffer in the Server protocol driver.

What is SMB?
Server Message Block (SMB), and its follow-on,
<http://www.microsoft.com/mind/1196/cifs.asp> Common Internet File System
(CIFS), is the Internet Standard protocol that Windows uses to share
files, printers, serial ports, and also to communicate between computers.
To do this, SMB uses named pipes and mail slots. In a networked
environment, servers make file systems and resources available to clients.
Clients make SMB requests for resources. Servers make SMB responses. This
is described as a client server, request-response protocol.

Does this vulnerability also affect CIFS?
Common Internet File System (CIFS) is an Internet Standard protocol. The
vulnerability described here resides specifically in Microsoft's
implementation of the protocol and not the protocol itself.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could remotely
view contents of the SMB buffers.

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
attacker could then retrieve information in the SMB buffers.

What systems are primarily at risk from the vulnerability?
Both workstations and servers are at risk. Servers could be at more risk,
especially if they support a large amount of SMB traffic.

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
<http://go.microsoft.com/fwlink/?LinkId=21169> Protect Your PC Web site.
IT professionals can visit the S
<http://go.microsoft.com/fwlink/?LinkId=21171> ecurity Guidance Center Web
site.

What does the update do?
The update removes the vulnerability by initializing the buffer prior to
responding to a client request.

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 Security.
The original article can be found at:
<http://www.microsoft.com/technet/security/Bulletin/MS06-035.mspx>
http://www.microsoft.com/technet/security/Bulletin/MS06-035.mspx



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