__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Flaw in Microsoft VM Could Enable System Compromise [Microsoft Security Bulletin MS02-069] December 13, 2002 14:00 GMT Number N-026 ______________________________________________________________________________ PROBLEM: Eight vulnerabilities have been identified in Microsoft virtual machine (VM) which revolve around COM objects, Java applets, and Java objects. SOFTWARE: All builds of the Microsoft VM up to and including build 5.0.3805 DAMAGE: The most serious of these vulnerabilities could allow an attacker to gain control of the user's systems using an untrusted Java applet to access COM objects. SOLUTION: Install build 3809 or later. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. An attacker would create a web page that, ASSESSMENT: when opened, exploits the desired vulnerability, and either host it on a web page or send it to a user as an HTML mail. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-026.shtml ORIGINAL BULLETIN: http://www.microsoft.com/security/security_bulletins /ms02-069.asp ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS02-069 *****] Microsoft Security Bulletin MS02-069 Flaw in Microsoft VM Could Enable System Compromise (810030) Originally posted: December 11, 2002 Summary Who should read this bulletin: Customers using Microsoft® Windows®. Impact of vulnerability: Eight vulnerabilities, the most serious of which would enable an attacker to gain control over another user’s system. Maximum Severity Rating: Critical Recommendation: Customers should install build 3809 or later of the Microsoft VM, as discussed below. Affected Software: Versions of the Microsoft virtual machine (Microsoft VM) are identified by build numbers, which can be determined using the JVIEW tool as discussed in the FAQ. All builds of the Microsoft VM up to and including build 5.0.3805 are affected by these vulnerabilities. End User Bulletin: An end user version of this bulletin is available at: http://www.microsoft.com/security/security_bulletins/ms02-069.asp Technical details Technical description: The Microsoft VM is a virtual machine for the Win32® operating environment. The Microsoft VM shipped in most versions of Windows (a complete list is available in the FAQ), as well as in most versions of Internet Explorer. A new version of the Microsoft VM is available, which includes all previously released fixes for the VM, as well as fixes for eight newly reported security issues. The attack vectors for all of the new issues would likely be the same. An attacker would create a web page that, when opened, exploits the desired vulnerability, and either host it on a web page or send it to a user as an HTML mail. The newly reported security issues are as follows: A security vulnerability through which an untrusted Java applet could access COM objects. By design, COM objects should only be available to trusted Java programs because of the functionality they expose. COM objects are available that provide functionality through which an attacker could take control of the system. A pair of vulnerabilities that, although having different underlying causes, would have the same effect, namely, disguising the actual location of the applet’s codebase. By design, a Java applet that resides on user storage or a network share has read access to the folder it resides in and all folders below it. The vulnerabilities provide methods by which an applet located on a web site could misrepresent the location of its codebase, to indicate that it resided instead on the user’s local system or a network share. A vulnerability that could enable an attacker to construct an URL that, when parsed, would load a Java applet from one web site but misrepresent it as belonging to another web site. The result would be that the attacker’s applet would run in the other site’s domain. Any information the user provided to it could be relayed back to the attacker. A vulnerability that results because the Microsoft VM doesn’t prevent applets from calling the JDBC APIs – a set of APIs that provide database access methods. By design, these APIs provide functionality to add, change, delete or modify database contents, subject only to the user’s permissions. A vulnerability through which an attacker could temporarily prevent specified Java objects from being loaded and run. A legacy security mechanism known as the Standard Security Manager provides the ability to impose restrictions on Java applets, up to and including preventing them from running altogether. However, the VM does not adequately regulate access to the SSM, with the result that an attacker’s applet could add other Java objects to the “banned” list. A vulnerability through which an attacker could learn a user’s username on their local system. The vulnerability results because one particular system property, user.dir, should not be available to untrusted applets but, through a flaw, is. While knowing a username would not in itself pose a security risk, it could be useful for reconnaissance purposes. A vulnerability that results because it’s possible for a Java applet to perform an incomplete instantiation of another Java object. The effect of doing so would be to cause the containing application – Internet Explorer – to fail. Mitigating factors: All of the vulnerabilities share a pair of common mitigating factors: The web-based attack vector would be blocked if the user had disabled Java applets in the Internet Explorer security zone in which the attacker’s web site rendered. The email vector would be blocked if the user were running any of several mail clients. Specifically, Outlook Express 6 and Outlook 2002 (which ships as part of Office XP) disable Java by default, and Outlook 98 and 2000 disable it if the Outlook Email Security Update has been installed. COM Object Access Vulnerability: The vulnerability represents a target of opportunity only. The attacker would have no means of ensuring that sensitive data would be located in system memory, cookies, the clipboard, or other locations. CODEBASE Spoofing Vulnerabilities: The attacker’s access to files, including those on remote shares, would be limited to those of the user. If the user had only limited permissions, so would the attacker. Domain Spoofing Vulnerability: The vulnerability could only be exploited if the user visited the attacker’s site en route to visiting a third-party site. The effect of exploiting the vulnerability would apply only to the current web session. JDBC API Vulnerability: To exploit this vulnerability, the attacker would need to know the names of each data source he or she wanted to access. In most cases, this would require the attacker to have insider knowledge of the user’s network. The attacker would gain only the user’s own permissions to the data sources. For instance, if the user had only read access to a particular database, so would the attacker. Standard Security Manager Access Vulnerability: The effect of exploiting this vulnerability would only persist during the current browser session. The vulnerability provides no means of modifying an applet’s functioning – only preventing it from running. User.dir Exposure Vulnerability: Knowing a user’s username would not, by itself, enable an attacker to take any action against the user. The sole value in learning this information would be for reconnaissance purposes, in the hope of using it in some future, unspecified attack. Incomplete Java object Instantiation Vulnerability: This vulnerability would only enable the attacker to cause Internet Explorer to fail – it would not enable the attacker to cause Windows itself, or any other applications, to fail. The user could restore normal operation by restarting the browser. Severity Rating: Severity Rating COM Object Access Vulnerability Critical CODEBASE Spoofing Vulnerabilities Important Domain Spoofing Vulnerability Moderate JDBC API Vulnerability Moderate Standard Security Manager Access Vulnerability Low User.dir Exposure Vulnerability Low Incomplete Java object Instantiation Vulnerability Low The above assessment is based on the types of systems affected by the vulnerability, their typical deployment patterns, and the effect that exploiting the vulnerability would have on them. Vulnerability identifiers: COM Object Access Vulnerability: CVE-CAN-2002-1257 CODEBASE Spoofing Vulnerabilities: CVE-CAN-2002-1258 Domain Spoofing Vulnerability: CVE-CAN-2002-1259 JDBC API Vulnerability: CVE-CAN-2002-1260 Standard Security Manager Access Vulnerability: CVE-CAN-2002-1261 User.dir Exposure Vulnerability: CVE-CAN-2002-1254 Incomplete Java object Instantiation Vulnerability: CVE-CAN-2002-1263 Tested Versions: Microsoft tested VM builds 5.0.3167 to assess whether they are affected by these vulnerabilities. Previous versions are no longer supported, and may or may not be affected by these vulnerabilities. Patch availability Download locations for this patch The patch is available to update existing Microsoft VMs via the Windows Update web site. Note: A version of the patch that can be downloaded and deployed throughout a network is available. Information on obtaining it is available in the FAQ. Additional information about this patch Installation platforms: The new VM build can be installed to update Microsoft VMs on the following versions of Windows: Microsoft Windows 95 Microsoft Windows 98 and 98SE Microsoft Windows Millennium Microsoft Windows NT 4.0, beginning with Service Pack 1 Windows 2000 Service Pack 2 or Service Pack 3 Microsoft Windows XP Gold or Service Pack 1. Inclusion in future service packs: The fixes included in this build will be included in all future VM builds. Reboot needed: Yes Patch can be uninstalled: No Superseded patches: The new VM build supersedes all builds prior to and including 5.0.3805 It includes fixes for all issues discussed in the following Microsoft security bulletins: MS99-031 MS99-045 MS00-011 MS00-059 MS00-075 MS00-081 MS02-013 MS02-052 Verifying patch installation: Knowledge Base article 810030 provides information to verify that you've installed the patch. Note: Regardless of the version number viewed from Jview, the registry key described in the above article should be the determining factor for proper installation of this patch Caveats: None Localization: Localized versions of this patch are available at the locations discussed in “Patch Availability”. Obtaining other security patches: Patches for other security issues are available from the following locations: Security patches are available from the Microsoft Download Center, and can be most easily found by doing a keyword search for "security_patch". Patches for consumer platforms are available from the WindowsUpdate web site Other information: Support: Microsoft Knowledge Base article 810030 discusses this issue and will be available approximately 24 hours after the release of this bulletin. Knowledge Base articles can be found on the Microsoft Online Support web site. Technical support is available from Microsoft Product Support Services. There is no charge for support calls associated with security patches. Security Resources: The Microsoft TechNet Security Web Site provides additional information about security in Microsoft products. Disclaimer: The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. Revisions: V1.0 (December 11, 2002): Bulletin Created. V1.1 (December 12, 2002): FAQ updated to provide additional references regarding using the Windows Update Catalog. [***** End Microsoft Security Bulletin MS02-069 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. 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