|
Brought to you by:
Suppliers of:
|
|
|
| |
A privilege elevation vulnerability exists in the way that the affected operating systems and programs access memory when they process COM structured storage files. This vulnerability could allow a logged on user to take complete control of the system.
A remote code execution vulnerability exists in OLE because of the way that it handles input validation. An attacker could exploit the vulnerability by constructing a malicious document that could potentially allow remote code execution. An attacker who successfully exploited this vulnerability could take complete control of an affected system. However, user interaction is required to exploit this vulnerability on Windows 2000, Windows XP, and Windows Server 2003. |
| |
Credit:
The original article can be found at: http://www.microsoft.com/technet/security/bulletin/MS05-012.mspx
|
| |
Affected Software:
* Microsoft Windows 2000 Service Pack 3 and Microsoft Windows 2000 Service Pack 4 - Download the update
* Microsoft Windows XP Service Pack 1 and Microsoft Windows XP Service Pack 2 - Download the update
* Microsoft Windows XP 64-Bit Edition Service Pack 1 (Itanium) - Download the update
* Microsoft Windows XP 64-Bit Edition Version 2003 (Itanium) - Download the update
* Microsoft Windows Server 2003 - Download the update
* Microsoft Windows Server 2003 for Itanium-based Systems - Download the update
* Microsoft Exchange 2000 Server Service Pack 3 (uses the Windows OLE component)
* Microsoft Exchange Server 2003 and Microsoft Exchange Server 2003 Service Pack 1 (uses the Windows OLE component)
* Microsoft Exchange Server 5.0 Service Pack 2 (uses the Windows OLE component)
* Microsoft Exchange Server 5.5 Service Pack 4 (uses the Windows OLE component)
* Microsoft Windows 98, Microsoft Windows 98 Second Edition (SE), and Microsoft Windows Millennium Edition (ME) Review the FAQ section of this bulletin for details about these operating systems.
* Microsoft Office XP Service Pack 3 (uses the Windows OLE component)
* Microsoft Office XP Service Pack 2 (uses the Windows OLE component)
* Microsoft Office XP Software:
* Outlook 2002
* Word 2002
* Excel 2002
* PowerPoint 2002
* FrontPage 2002
* Publisher 2002
* Access 2002
* Microsoft Office 2003 Service Pack 1 (Uses the Windows OLE component)
* Microsoft Office 2003 (Uses the Windows OLE component)
* Microsoft Office 2003 Software:
* Outlook 2003
* Word 2003
* Excel 2003
* PowerPoint 2003
* FrontPage 2003
* Publisher 2003
* Access 2003
* InfoPath 2003
* OneNote 2003
Note Any application that uses the Windows OLE component could also be vulnerable to this issue. This list of affected software documents the most likely attack vectors. We recommend customers install this security update immediately. Installing this security update will address this vulnerability in any application that uses the Windows OLE component.
CVE Information:
COM Structured Storage Vulnerability - CAN-2005-0047
Input Validation Vulnerability - CAN-2005-0044
Mitigating Factors for COM Structured Storage Vulnerability:
An attacker must have valid logon credentials and be able to log on locally to exploit this vulnerability. The vulnerability could not be exploited remotely or by anonymous users.
FAQ for COM Structured Storage Vulnerability:
What is the scope of the vulnerability?
This is a privilege elevation vulnerability. An attacker who successfully exploited this vulnerability could 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. To attempt to exploit the vulnerability, an attacker must be able to log on locally to the system and run a program.
What causes the vulnerability?
The way that the affected operating systems and programs access memory when they process COM structured storage files or objects.
What are COM Structured Storage files or objects?
Traditional file systems encounter challenges when they attempt to efficiently store multiple kinds of objects in one document. COM provides a solution: a file system within a file. COM structured storage defines how to treat a single file entity as a structured collection of two types of objects. These two types of objects, storages and streams, behave like directories and files. This scheme is called structured storage. The purpose of structured storage is to reduce the performance penalties and overhead associated with storing separate objects in a flat file. For more information about COM structured storage files, visit the following MSDN 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?
To exploit the vulnerability, an attacker must be able to log on locally to a system and run a program.
How could an attacker exploit the vulnerability?
To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially-crafted application that could exploit the vulnerability. The attacker could then gain complete control over the affected system.
What systems are primarily at risk from the vulnerability?
Workstations and terminal servers are primarily at risk. Servers could be at more risk if users who do not have sufficient administrative permissions are given the ability to log on to servers and to run programs. However, best practices strongly discourage allowing this.
Could the vulnerability be exploited over the Internet?
No. An attacker must be able to log on to the specific system that is targeted for attack. An attacker cannot load and run a program remotely by using this vulnerability.
What does the update do?
The update removes the vulnerability by modifying the way that the affected operating systems validate the use of memory regions when they process COM structured storage files or objects.
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.
Mitigating Factors for Input Validation Vulnerability:
* An attacker who successfully exploited this vulnerability could gain the same user rights as the local user or program that processed the malicious document. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
* In a Web-based attack scenario, an attacker would have to host a Web site that contains a Web page that is used to exploit this vulnerability. An attacker would have no way to force users to visit a malicious Web site. Instead, an attacker would have to persuade them to visit the Web site, typically by getting them to click a link that takes them to the attacker's Web site. After they click the link, they would be prompted to perform several actions. An attack could only occur after they performed these actions.
* User interaction is required to exploit this vulnerability on Windows 2000, Windows XP, and Windows Server 2003. For an attack to be successful by sending an e-mail message to a locally logged on user, the user must open an attachment that contains a malicious OLE object.
Workarounds for Input Validation Vulnerability:
Microsoft has tested the following workarounds. While 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.
* Do not open or save documents that you receive from untrusted sources.
This vulnerability could be exploited when a user opens a document that contains a malicious OLE object. Open documents that are sent only from trusted sources.
* Block MS-TNEF to help protect against attempts to exploit this vulnerability through SMTP e-mail.
Systems can be configured to block certain types of files sent through e-mail. Microsoft TNEF encoded e-mails, commonly known as Rich Text Formatted e-mail, can contain malicious OLE objects. These e-mails contain a file attachment that is usually named Winmail.dat to store the TNEF information. Blocking this file and blocking the application/ms-tnef MIME type could help protect both Exchange Servers and other affected programs from attempts to exploit this vulnerability if customers are unable to install the available security update. There are Exchange Server configuration settings, such as setting Exchange rich-text format to Never used or editing the registry and disabling TNEF processing that do not mitigate this vulnerability. To help protect an Exchange Server computer from attacks through SMTP, block the Winmail.dat file and all application/ms-tnef MIME type content before it reaches the Exchange Server computer. Note Exchange supports other messaging protocols such as X.400 that would not be protected using these workarounds. We recommend requiring authentication on all other client and message transport protocols to help prevent attacks using these protocols.
Note Filtering only for attachments with the filename Winmail.dat may not sufficient protect your system. A malicious file attachment could be given another filename that could then be processed by the Exchange Server computer. To help protecte against these types of e-mails, you must also block all application/ms-tnef MIME type content.
While there are many ways to block the Winmail.dat file and other TNEF content, here are some suggestions:
* ISA Server 2000 SMTP Message Screener could be used to block all file attachments or just the Winmail.dat file. Blocking all file attachments is the recommendation to provide the most protection for this issue using ISA Server 2000 because ISA Server 2000 does not support blocking content based on MIME content types. See Microsoft Knowledge Base Article 31532 for more information.
* ISA Server 2000 SMTP Filter could be used to block all file attachments or just the Winmail.dat file. Blocking all file attachments is the recommendation to provide the most protection for this issue using ISA Server 2000 because ISA Server 2000 does not support blocking content based on MIME content types. See Microsoft Knowledge Base Article 320703 for more information.
* ISA Server 2004 SMTP Filter and Message Screener could be used to block all file attachments or just the Winmail.dat file. Blocking all file attachments is the recommendation to provide the most protection for this issue using ISA Server 2004 because ISA Server 2004 does not support blocking content based on MIME content types. See Microsoft Knowledge Base Article 888709 for more information.
* Use third party e-mail filters to block the all application/ms-tnef MIME content type before it is sent to the Exchange Server or vulnerable application.
Impact of workaround: Blocking TNEF attachments will result in the loss of Rich Text Formatted e-mail. In some cases, users could receive blank e-mails instead of the original content or not receive the e-mail at all. Blocking the TNEF attachments will not affect HTML encoded or plain text e-mail messages. This procedure should only be performed if you are unable to install the available security update or a security update is not publicly available for your configuration.
* Require authentication for connections to Exchange for all client and message transport protocols.
Requiring authentication for all connections made to the Exchange Server computer will help protect against anonymous attacks. This will not protect against an attack from a malicious user who can successfully authenticate.
Impact of workaround: Anonymous communication from clients through IMAP, POP3, HTTP, LDAP, SMTP and NNTP will no longer be possible. Server to server anonymous communication through RPC, X.400, foreign gateway, and third-party connector protocols will also no longer be possible. In most Exchange server configurations, authenticated access is already required for all protocols except SMTP. If all application/ms-tnef MIME type message parts and the Winmail.dat file can be blocked, as describe in the previous workaround, anonymous SMTP connections could still be accepted.
* Do not accept incoming public newsfeeds through the NNTP protocol.
Incoming newsfeeds are not enabled by default for Exchange Server. If you have subscribed to incoming newsfeeds from public newsgroups, an attacker could post a malicious message to such a newsgroup. Even if you require authentication between the news server and your Exchange Server computer, such a message could still be transferred to your Exchange Server computer. Therefore, you should disable incoming newsfeeds from any NNTP server that could let a user post a malicious message.
Impact of workaround: Exchange access to public newsgroup feeds will no longer be possible.
Read e-mail messages in plain text format if you are using Outlook 2002 or a later version, or Outlook Express 6 SP1 or a later version, to help protect yourself from the e-mail attack vector.
Microsoft Outlook 2002 users who have applied Office XP Service Pack 1 or a later version and Microsoft Outlook Express 6 users who have applied Internet Explorer 6 Service Pack 1 or a later version can enable this setting and view e-mail messages that are not digitally signed or e-mail messages that are not encrypted in plain text only.
Digitally signed e-mail messages or encrypted e-mail messages are not affected by the setting and may be read in their original formats. For more information about how to enable this setting in Outlook 2002, see Microsoft Knowledge Base Article 307594.
For information about this setting in Outlook Express 6, see Microsoft Knowledge Base Article 291387.
Impact of Workaround: E-mail messages that are viewed in plain text format will not contain pictures, specialized fonts, animations, or other rich content. Additionally:
* The changes are applied to the preview pane and to open messages.
* Pictures become attachments so that they are not lost.
* Because the message is still in Rich Text or HTML format in the store, the object model (custom code solutions) may behave unexpectedly.
FAQ for Input Validation Vulnerability:
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. If a user or program is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could 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. Users and programs whose accounts are configured to have fewer user rights on the system could be less impacted than users or programs that operate with administrative user rights. User interaction is required to exploit this vulnerability on Windows 2000, on Windows XP, and on Windows Server 2003.
What causes the vulnerability?
An unchecked buffer in the process that OLE uses to validate data.
What is OLE?
By using OLE technology, an application can provide embedding and linking support. OLE is the technology that applications use to create and edit compound documents. These are documents of one format, such as a Microsoft Word document, that contain embeddings of (or links to) documents of another format, such as Microsoft Excel. OLE 2.0 takes OLE even further by allowing in-place editing. Instead of launching a new application when an OLE object is activated, the user instead sees a new set of menu items inside their existing application. For more information about OLE, visit the following MSDN 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.
How could an attacker exploit the vulnerability?
On Exchange Server 5.0, Exchange Server 5.5, Exchange 2000 Server, and Exchange Server 2003 any anonymous user who could deliver a specially crafted message to the affected system could try to exploit this vulnerability. User interaction is required to exploit this vulnerability on Windows 2000, Windows XP, and Windows Server 2003. For an attack to be successful by sending an e-mail message to a locally logged on user, the user must open an attachment that contains a malicious OLE object. Many different types of attached documents can contain the affected OLE Object types. All Office file types as well as many other third-party file types could contain a malicious OLE Object.
What systems are primarily at risk from the vulnerability?
Exchange Servers and any program using OLE that runs on an affected operating system are at risk from this vulnerability. Programs that run at an elevated level of user rights could be at an increased level of risk from this vulnerability. Exchange Servers are primarily at risk because an attacker could try to exploit this vulnerability without any required user interaction, and because Exchange Servers typically run with elevated user rights. Exchange Server that contain NNTP newsgroups from the Internet or contain postings from anonymous users could also be vulnerable to this issue.
Any application that uses the Windows OLE component could also be vulnerable to this issue. The list of affected software documents the most likely attack vectors. Installing this security update will address this vulnerability in any application that uses the Windows OLE component.
Are Windows 98, Windows 98 Second Edition or Windows Millennium Edition critically affected by this vulnerability?
No. Although Windows 98, Windows 98 Second Edition, and Windows Millennium Edition do contain the affected component, the vulnerability is not critical. For more information about severity ratings, visit the following Web site.
Could the vulnerability be exploited over the Internet?
Yes. An attacker could try to exploit this vulnerability over the Internet.
What does the update do?
The update removes the vulnerability by modifying the way that OLE 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 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.
|
|
|
|
|
