This was a big week for the bad guys! Windows users need to do a lot of patching because the newly discovered vulnerabilities are numerous and dangerous. (#1 through #7 and #10 and #11 below). If you are using Exchange, pay particular attention to #7. Computer Associates (#12), Symantec (#8) and F-Secure (#9) users should also act quickly.
Better news: San Diego (right on the ocean) is the site of this year's SANS 2005 - the largest security training conference, by far. The early registration deadline is in two weeks. Details at: http://www.sans.org/sans2005
@RISK is the SANS community's consensus bulletin summarizing the most important vulnerabilities and exploits identified during the past week and providing guidance on appropriate actions to protect your systems (PART I). It also includes a comprehensive list of all new vulnerabilities discovered in the past week (PART II).
***************This issue sponsored by AlterPoint***********************
FREE Network Configuration Management eBook from AlterPoint Want expert advice on Network Change & Configuration Management (NCCM)? In this FREE eBook, "Tips & Tricks Guide to Network Configuration Management" you'll get over 120-pages of how-to advice on change management techniques and best practices, troubleshooting configuration errors, enhancing network security, and selecting and deploying a NCCM solution. Download your copy today. http://www.alterpoint.com/support/r?c=701300000000xH9
*************************************************************************
Part I is researched and compiled by Rohit Dhamankar at TippingPoint (rohitd_at_tippingpoint.com), a division of 3Com, as a by-product of that company's continuous effort to ensure that its intrusion prevention products effectively block exploits using known vulnerabilities. TippingPoint's analysis is complemented by input from a council of security managers from twelve large organizations who confidentially share with SANS the specific actions they have taken to protect their systems. A detailed description of the process may be found at http://www.sans.org/newsletters/cva/#process
Description: Windows license logging service was originally designed to manage licenses for Microsoft server products. The license logging is an RPC service that can be reached via "llsrpc" SMB named pipe. This service contains a buffer overflow that may be exploited to execute arbitrary code with "SYSTEM" privileges. Since the service is an RPC service, the buffer overflow may be triggered by a specially crafted DCE/RPC packet to the service's RPC interface. Note that the service runs by default on Windows NT, 2000, Small Business Server 2000 and Small Business Server 2003 servers. However, only NT and 2000 SP3 servers are critically affected as remote "anonymous" users can establish connection to the service. On Windows 2000 SP4 and 2003 servers, the service is not accessible to anonymous users i.e. only authorized users can exploit the overflow. The technical details regarding how to trigger the flaw have not been posted.
Status: Patches are available as described in the Microsoft Security Bulletin MS05-010. A general workaround is to block ports 139/tcp and 445/tcp at the network perimeter. For NT and Windows 2000 SP3 server systems, the Microsoft advisory describes how to edit the registry to stop "anonymous" users from accessing the service.
Council Site Actions: Most of the council sites are responding to this item. Some are already in the process of distributing the patch while others plan to deploy the patch during their next regularly scheduled patch update process. One site commented they have this feature turned off by default and another site has very few affected hosts, but will patch as the hosts are discovered.
Description: Microsoft has released another cumulative patch for Internet Explorer, which fixes previously disclosed as well as privately reported vulnerabilities. (a) Drag and Drop Vulnerability: This vulnerability was disclosed in October 2004, and has been discussed in the previous issues of the @RISK newsletter. A malicious HTML page or email can completely compromise a user's system by installing arbitrary files in the "Startup" folder. Multiple proof-of-concept exploits have already been posted. Note that the patches MS05-008 as well as MS05-014 are required to completely patch this vulnerability. (b) URL Decoding Zone Spoofing Vulnerability: Internet Explorer contains a vulnerability in decoding specially constructed URLs. Such URLs can lead to Internet Explorer downloading malicious code from untrusted servers and executing the code in the context of the "Local Security" zone. The problem occurs because Internet Explorer decodes URLs containing hex-encoded characters twice. (c) DHTML Method Heap Memory Corruption: Certain Dynamic HTML method(s) contain a flaw that can be leveraged to corrupt Internet Explorer's heap memory. Specially crafted webpage or an HTML email may exploit this flaw to execute arbitrary code on a Windows client. The discoverer has not yet disclosed any technical details. (d) Channel Definition Format Cross Domain Vulnerability: Internet Explorer's "Active Channel" technology allows users to group web sites by content. A channel file specifies how the content from a website is displayed, and the frequency the content is automatically updated. Internet Explorer contains a vulnerability in handling "channel" files. A specially crafted channel file can lead to execution of arbitrary script code in the context of the "Local Security Zone", thereby completely compromising the client system. The technical details regarding how to trigger this flaw have not been posted.
Status: Patches referenced in the Microsoft Security Bulletin MS05-014 and MS05-008.
Council Site Actions: All council sites are responding to this item. Some sites are deploying the patch on an accelerated schedule (already in progress for some sites) while other sites are planning to deploy during their next regularly scheduled patch process.
Description: Windows DHTML Edit ActiveX control, designed for editing web site contents, contains a cross-domain vulnerability. The problem occurs because the control's "execScript" function does not sufficiently validate a Window's domain prior to executing script code in that domain. Hence, a malicious webpage or an HTML email can leverage this flaw to execute arbitrary code in the client's "Local Computer" zone. The technical details and proof-of-concept code have been posted since December 2004.
Status: Patches referenced in the Microsoft Security Bulletin MS05-013.
Council Site Actions: All council sites are responding to this item. Some sites are deploying the patch on an accelerated schedule (already in progress for some sites) while other sites are planning to deploy during their next regularly scheduled patch process.
Description: This vulnerability in Microsoft Office XP can be exploited via Internet Explorer to execute arbitrary code on a client system. The exploitation proceeds as follows: (a) An attacker constructs a link such as http://www.evil.com/foo.doc%00<long string> and posts the link on a webpage, or sends it to potential victims in an HTML email. (b) When IE parses the malicious link, it requests "foo.doc" from the attacker's webserver. IE then passes foo.doc along with the "long string" to Microsoft Word (the program associated with the ".doc" extension), which triggers the overflow. Note that Internet Explorer automatically opens a ".doc" or ".rtf" or ".ppt" file. Hence, no user interaction is required to exploit this flaw. A proof-of-concept exploit has been publicly posted.
Status: Patches referenced in the Microsoft Security Bulletin MS05-005.
Council Site Actions: All but one of the council sites are responding to this item. Some sites are deploying the patch on an accelerated schedule (already in progress for some sites) while other sites are planning to deploy during their next regularly scheduled patch process. The remaining council site does not provide automated support for MS Office updates. They do plan to advise users to go to the Office Update site and select "Check for Updates". However, they do not have statistics about the fraction of the user community that is actually updating their systems.
Description: Portable Network Graphics (PNG) is a format for rendering images and used as an alternative to GIF. The following Microsoft products contain buffer overflow vulnerabilities in processing PNG images: (a) Windows Media Player: A PNG image file with a large width or height parameter can trigger a buffer overflow in the Windows media player. In order to exploit the flaw, an attacker can craft a media player file (i.e. a file with a ".asf", ".asx", ".wma", or ".wmv" extension) that references a malicious PNG file. The attacker can then post the crafted media player file on a webserver, or send it in an HTML email. Note that Windows will automatically download and open the media player file. Hence, browsing a malicious webpage or opening an HTML email is sufficient to trigger the vulnerability. The attacker can leverage the flaw to execute arbitrary code on the client system. The technical details have been posted. (b) Windows and MSN Messenger: These products include a vulnerable version of the open-source "libpng" library. This library has been found to contain multiple buffer overflow vulnerabilities that have been discussed in a previous issue of the @RISK newsletter. However, exploiting these vulnerabilities is either difficult or requires user interaction. In the case of Windows Messenger, an attacker would need to spoof the ".NET" Messenger service or conduct a man-in-the-middle attack to exploit the flaw; To exploit the flaw in MSN Messenger, the attacker would need to entice a victim to add him to the victim's contact list prior to sending the malicious PNG image. The proof-of-concept exploits for this flaw have been posted since August 2004. An exploit targeting MSN Messenger has also been released.
Status: Patches referenced in the Microsoft Security Bulletin MS05-009.
Council Site Actions: All council sites are responding to this item. Some sites are deploying the patch on an accelerated schedule (already in progress for some sites) while other sites are planning to deploy during their next regularly scheduled patch process.
Description: Server Message Block (SMB) protocol is used by Windows to share files and printers and to communicate between computers. The client implementation of the SMB protocol contains a buffer overflow that can be triggered by a malformed SMB server response. Specifically, a SMB "transaction" response associated with a file query or MS-RPC call, may be used for exploitation purposes. A malicious SMB server can leverage the flaw to execute arbitrary code on a client with "kernel" privileges i.e. obtain a complete control over the client. In order to exploit the flaw, a remote attacker would need to entice a client to connect to his malicious SMB server. This can be accomplished via a link such as "file://evil.com/evil.txt" on a webpage or in an HTML email. An attacker on the same subnet as the victim may be able to use certain broadcast messages to initiate connection from the victim. The technical details and a proof-of-concept exploit have been publicly posted.
Status: Patches referenced in the Microsoft Security Bulletin MS05-011. A workaround to prevent attacks originating from the Internet is to block ports 139/tcp and 445/tcp at the network perimeter.
Council Site Actions: All council sites are responding to this item. Some sites are deploying the patch on an accelerated schedule (already in progress for some sites) while other sites are planning to deploy during their next regularly scheduled patch process. Several of the sites expressed concerns about a multi-vector worm built using this vulnerability. One of these sites plans to monitor for such exploits and will change their patch install plan to the "fire-drill" variety, if necessary.
Description: Microsoft Object Linking and Embedding (OLE) technology enables embedding or linking a Microsoft document inside another document. For instance, with OLE it is possible to embed a Word file in a PowerPoint presentation. OLE processing contains a buffer overflow that can be exploited by a specially crafted document. A malicious webpage or an HTML email may exploit this flaw to execute arbitrary code on a Windows client. However, such an attack requires user interaction. Exchange servers are critically affected by this vulnerability as any user, who can deliver the crafted document to the Exchange server, may leverage the flaw. No technical details regarding how to craft a malicious document have been publicly posted.
Status: Patches referenced in the Microsoft Security Bulletin MS05-012. The patch also fixes another privilege-escalation vulnerability in the Windows COM component.
Council Site Actions: All but one of the council sites are responding to this item. Some sites are deploying the patch on an accelerated schedule (already in progress for some sites) while other sites are planning to deploy during their next regularly scheduled patch process. The remaining council site does not plan to take any action since this is a local escalation vulnerability only.
Description: A number of Symantec enterprise and consumer products contain a heap-based buffer overflow vulnerability. The overflow can be triggered by a malicious UPX (a compression format) packed files. The problem lies in the "DEC2EXE" parsing engine used to decompress the UPX packed files for scanning. An unauthenticated attacker can compromise any client or server running the vulnerable Symantec product by delivering a malicious UPX file via email or web. The technical details regarding how to trigger the flaw have been publicly posted.
Status: Vendor confirmed, patches available.
Council Site Actions: Due to late breaking nature of the vulnerability, we were unable to solicit council site input.
Description: A number of F-Secure anti-virus products contain a heap-based buffer overflow vulnerability. The overflow can be triggered by a malicious ARJ (a compression format) archive. An unauthenticated attacker can compromise any client or server running the vulnerable F-Secure product by delivering a malicious ARJ archive via email or web. Limited technical details regarding how to trigger the flaw have been publicly posted.
Status: Vendor confirmed, patches available.
Council Site Actions: Due to late breaking nature of the vulnerability, we were unable to solicit council site input.
Description: Windows Hyperlink object library provides functions and interfaces to handle hyperlinks in various Windows programs. This library contains a buffer overflow that can be triggered by a specially crafted hyperlink. The likely way an attacker would exploit this vulnerability is by enticing a victim to click the crafted link in a webpage or in an HTML email. The flaw can be leveraged to potentially execute arbitrary code on the victim's system. No technical details that may be used to construct a malicious hyperlink have been posted yet.
Status: Patches referenced in the Microsoft Security Bulletin MS05-015.
Council Site Actions: All council sites plan to deploy the patch during their next regularly scheduled patch update process.
Description: Microsoft's ASP.NET software is used to create dynamic web-based applications. The software reportedly runs on 2.9 million web servers. ASP.NET contains a vulnerability that may be exploited to bypass Forms-based authentication or Windows-based authentication to obtain unauthorized access to password protected files on the web server. The authentication checks can be bypassed by accessing the password protected files directly via an HTTP request that contains a "\" (backslash) or "%5c" (hex encoded backslash), instead of a "/" in the URL. It is reported that inserting "%20" (hex encoded space) in the URL also bypasses the authentication checks. An attacker may exploit the flaw to obtain sensitive information that may be used to further compromise the web server.
Status: Patches referenced in the Microsoft Security Bulletin MS05-004.
Council Site Actions: All council sites plan to deploy the patch during their next regularly scheduled patch update process.
Description: Computer Associates BrightStor ARCserve Backup products provide backup services for Windows, NetWare, Linux and UNIX. The products detect other backup servers on a network by using the "v11" discovery service that runs on port 41524/udp. This service contains a stack-based buffer overflow that can be triggered by a UDP packet over 967 bytes. The overflow can be exploited to execute arbitrary code on the server with "Local System" privileges. Note that since the service is UDP-based, it is easy to spoof the discovery packets to trigger the overflow.
Status: Vendor confirmed, patches available. A workaround is to block port 41524/udp at the network perimeter.
Council Site Actions: The affected software is not in production or widespread use, or is not officially supported at any of the council sites. They reported that no action was necessary.
Description: Eudora reportedly contains a vulnerability that can be exploited to execute arbitrary code. The flaw can be triggered by simply previewing a specially crafted email, stationery or mailbox files. No technical details regarding the flaw have been posted yet. The discoverers report they will release the technical details in May 2005.
Status: Eudora confirmed, upgrade to version 6.2.1.
Council Site Actions: Only one of the reporting council sites is running the affected software. Eudora is their most popular email program and the potential impact of this vulnerability could be severe. They plan to send out a mass mailing to inform all affected users.
This list is compiled by the Qualys Security Research Team (research_at_qualys.com ) as part of that company's ongoing effort to ensure its vulnerability management web service tests for all known vulnerabilities that can be scanned. As of this week Qualys scans for 4064 unique vulnerabilities. For this special SANS community listing, Qualys also includes vulnerabilities that cannot be scanned remotely.
(c) 2005. All rights reserved. The information contained in this newsletter, including any external links, is provided "AS IS," with no express or implied warranty, for informational purposes only. In some cases, copyright for material in this newsletter may be held by a party other than Qualys (as indicated herein) and permission to use such material must be requested from the copyright owner.
==end==
Subscriptions: @RISK is distributed free of charge to people responsible for managing and securing information systems and networks. You may forward this newsletter to others with such responsibility inside or outside your organization.
To subscribe, at no cost, go to https://portal.sans.org where you may also request subscriptions to any of SANS other free newsletters.
To change your subscription, address, or other information, visit http://portal.sans.org
Copyright 2005. All rights reserved. No posting or reuse allowed, other that listed above, without prior written permission.