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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2008.0883 -- [Win] InstallShield / Macrovision / Acresso FLEXnet Connect insecurely retrieves and executes scripts 24 September 2008 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: InstallShield / Macrovision / Acresso FLEXnet Connect Publisher: US-CERT Operating System: Windows Impact: Execute Arbitrary Code/Commands Access: Remote/Unauthenticated CVE Names: CVE-2008-1093 Original Bulletin: http://www.kb.cert.org/vuls/id/837092 Revision History: September 24 2008: Added CVE Name September 17 2008: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- Vulnerability Note VU#837092 InstallShield / Macrovision / Acresso FLEXnet Connect insecurely retrieves and executes scripts Overview Acresso FLEXnet Connect executes scripts that are insecurely retrieved from a remote web server, which can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system. I. Description Acresso FLEXnet Connect is a software package that allows vendors to provide updates to applications. FLEXnet Connect-enabled software has the ability to * Check for updates from the software publisher * Receive update files and messages from the software publisher * Install software updates, including the ability to do so silently * Collect and transmit system information, such as machine name, operating system, IP address, or other hardware details, such as network or video card properties * Log and transmit each time an application is started, terminated, or when a specific feature within the application is used Acresso FLEXnet Connect was formerly known as Macrovision FLEXnet Connect, and before that it was known as InstallShield Update Service. The FLEXnet Connect client software communicates with centralized servers to check for updates and other product information on a periodic basis. Updates can also be triggered by using Internet Explorer to visit a web page that uses the FLEXnet Connect ActiveX control, which is provided by agent.exe. When connecting to the server, the client can receive special instructions (rules) to assist in evaluating whether an update is relevant. These instructions are provided by a GetRules.asp page on a web server. These rules are presented in a scripting language, such as VBScript. FLEXnet Connect retrieves rules insecurely in that it uses unsigned and unencrypted communication using the HTTP protocol, which can allow an attacker to inject code that will be executed on the client system. This can happen in a number of ways, including 1. Compromising the FLEXnet Connect servers directly. 2. Filtering client system traffic through a malicious proxy. 3. Compromising DNS servers or otherwise modifying the host name lookup methodology of a client system. Depending on how the vendor has configured the FLEXnet Connect components, the check for updates may occur on a periodic basis, every time an application is launched, when a user checks for updates manually, or if a web page that uses the FLEXnet ActiveX control is visited. Any software that has been packaged with the vulnerable InstallShield, Macrovision, or Acresso components may be vulnerable. II. Impact By modifying the rule script that is sent to a FLEXnet Connect client, a remote unauthenticated attacker may be able to execute arbitrary code on a vulnerable system. III. Solution We are currently unaware of a practical solution to this problem. Please consider the following workarounds: Restrict access to GetRules.asp Enterprises that have proxy capabilities could disable access to the GetRules.asp URLs that are used to download the script instructions, however this may have consequences to programs that depend on the rules for determining patch applicability. Disable the DWUpdateService ActiveX control in Internet Explorer The vulnerable ActiveX control can be disabled in Internet Explorer by setting the kill bit for the following CLSIDs: {551E5190-19C7-4626-9D54-FB20355E6467} {8D9BB053-FEE5-4411-B6F5-F1E37DDC3106} {EE4E49B0-38EC-4C23-A7A6-2E190B5E3418} {FFF2D28F-E4EE-44D9-8104-8E71556757F6} More information about how to set the kill bit is available in Microsoft Support Document 240797. Alternatively, the following text can be saved as a .REG file and imported to set the kill bit for this control: Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{551E5190-19C7-4626-9D54-FB20355E6467}] "Compatibility Flags"=dword:00000400 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{8D9BB053-FEE5-4411-B6F5-F1E37DDC3106}] "Compatibility Flags"=dword:00000400 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{EE4E49B0-38EC-4C23-A7A6-2E190B5E3418}] "Compatibility Flags"=dword:00000400 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{FFF2D28F-E4EE-44D9-8104-8E71556757F6}] "Compatibility Flags"=dword:00000400 Note that this list of CLSIDs may not be complete. Different versions of FLEXnet Connect or InstallShield Update Service use different CLSIDs for the ActiveX control that can be used to trigger updates. Restrict access to the FLEXnet Conect client components The vulnerable update components can be disabled by restricting access to the ISSCH.EXE and ISUSPM.EXE components on Microsoft Windows Systems. These executable files are for the InstallShield Update Service Scheduler and the Macrovision FLEXnet Connect Update Manager, respectively. These programs are used to periodically check for software updates using FLEXnet Connect. Users may also wish to rename the "\Program Files\Common Files\InstallShield\UpdateService" or related UpdateManager folders of other products to prevent automated execution of these programs until a fix is provided. Note that this may interfere with a product's ability to retrieve updates, including security fixes. Disable ActiveX Disabling ActiveX controls in the Internet Zone (or any zone used by an attacker) appears to prevent exploitation of this and other ActiveX vulnerabilities. Instructions for disabling ActiveX in the Internet Zone can be found in the "Securing Your Web Browser" document. Systems Affected Vendor Status Date Updated Acresso Vulnerable 16-Sep-2008 Corel Corporation Vulnerable 16-Sep-2008 InstallShield Vulnerable 16-Sep-2008 Intel Corporation Not Vulnerable 16-Sep-2008 Macrovision Vulnerable 15-Sep-2008 Roxio Vulnerable 16-Sep-2008 References http://www.simplicity.net/vuln/CVE-2008-1093.txt Credit Thanks to Brian Dowling of Simplicity Communications for reporting this vulnerability. This document was written by Will Dormann. Other Information Date Public 16/09/2008 Date First Published 16/09/2008 13:48:11 Date Last Updated 16/09/2008 CERT Advisory CVE-ID(s) CVE-2008-1093 NVD-ID(s) CVE-2008-1093 US-CERT Technical Alerts Metric 9.90 Document Revision 28 - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. 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Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 If you believe that your computer system has been compromised or attacked in any way, we encourage you to let us know by completing the secure National IT Incident Reporting Form at: http://www.auscert.org.au/render.html?it=3192 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQCVAwUBSNq5ASh9+71yA2DNAQL2NgQAk2b3c+d1PhGbh3+TujEwtzTKWRSXBEeX z1v35HOqVn4q/dPI3cC1aVbbSd2afvqASwsB+YvFeQ0xzaXxmvGIpkv3yIjyzj4Z LPhWlaJxofLkn3jj37hF9p1+cvesURLst3zKfXzbhtLT1Os5JnGJhr783Gc5DH1k oHR5hTY0M+I= =8asa -----END PGP SIGNATURE-----