==================================================================== CERT-Renater Note d'Information No. 2015/VULN171 _____________________________________________________________________ DATE : 09/09/2015 HARDWARE PLATFORM(S): / OPERATING SYSTEM(S): Systems running Internet Explorer versions 7, 8, 9, 10, 11. ====================================================================== https://technet.microsoft.com/en-us/library/security/MS15-094 ______________________________________________________________________ MS15-094 - Cumulative Security Update for Internet Explorer (3089548) Bulletin Number: MS15-094 Bulletin Title: Cumulative Security Update for Internet Explorer Severity: Critical KB Article: 3089548 Version: 1.0 Published Date: September 8, 2015 Executive Summary This security update resolves vulnerabilities in Internet Explorer. The most severe of the vulnerabilities could allow remote code execution if a user views a specially crafted webpage using Internet Explorer. An attacker who successfully exploited these vulnerabilities could gain the same user rights as the current user. Customers whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights. This security update is rated Critical for Internet Explorer 7 (IE 7), Internet Explorer 8 (IE 8), Internet Explorer 9 (IE 9), Internet Explorer 10 (IE 10), and Internet Explorer 11 (IE 11) on affected Windows clients, and Moderate for Internet Explorer 7 (IE 7), Internet Explorer 8 (IE 8), Internet Explorer 9 (IE 9), Internet Explorer 10 (IE 10), and Internet Explorer 11 (IE 11) on affected Windows servers. For more information, see the Affected Software section. Affected Software Internet Explorer 7 Internet Explorer 8 Internet Explorer 9 Internet Explorer 10 Internet Explorer 11 Windows Vista Service Pack 2 Windows Vista x64 Edition Service Pack 2 Windows Server 2008 for 32-bit Systems Service Pack 2 Windows Server 2008 for x64-based Systems Service Pack 2 Windows Server 2008 for Itanium-based Systems Service Pack 2 Windows 7 for 32-bit Systems Service Pack 1 Windows 7 for x64-based Systems Service Pack 1 Windows Server 2008 R2 for x64-based Systems Service Pack 1 Windows Server 2008 R2 for Itanium-based Systems Service Pack 1 Windows 8 for 32-bit Systems Windows 8 for x64-based Systems Windows Server 2012 Windows RT Windows 8.1 for 32-bit Systems Windows 8.1 for x64-based Systems Windows Server 2012 R2 Windows RT 8.1 Windows 10 for 32-bit Systems[2] Windows 10 for x64-based Systems[2] [1]This update is available via Windows Update. [2]The Windows 10 update is cumulative. In addition to containing non-security updates, it also contains all of the security fixes for all of the Windows 10-affected vulnerabilities shipping with this months security release. See Microsoft Knowledge Base Article 3081444 for more information and download links. Vulnerability Information Multiple Memory Corruption Vulnerabilities in Internet Explorer Remote code execution vulnerabilities exist when Internet Explorer improperly accesses objects in memory. These vulnerabilities could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user. An attacker could host a specially crafted website that is designed to exploit these vulnerabilities through Internet Explorer, and then convince a user to view the website. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements by adding specially crafted content that could exploit these vulnerabilities. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by getting them to click a link in an instant messenger or email message that takes users to the attacker's website, or by getting them to open an attachment sent through email. An attacker who successfully exploited these vulnerabilities could gain the same user rights as the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited these vulnerabilities could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from these vulnerabilities. The update addresses the vulnerabilities by modifying how Internet Explorer handles objects in memory. The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list: Vulnerability title CVE number publicly disclosed Exploited Memory Corruption Vulnerability CVE-2015-2485 No No Memory Corruption Vulnerability CVE-2015-2486 No No Memory Corruption Vulnerability CVE-2015-2487 No No Memory Corruption Vulnerability CVE-2015-2490 No No Memory Corruption Vulnerability CVE-2015-2491 No No Memory Corruption Vulnerability CVE-2015-2492 No No Memory Corruption Vulnerability CVE-2015-2494 No No Memory Corruption Vulnerability CVE-2015-2498 No No Memory Corruption Vulnerability CVE-2015-2499 No No Memory Corruption Vulnerability CVE-2015-2500 No No Memory Corruption Vulnerability CVE-2015-2501 No No Memory Corruption Vulnerability CVE-2015-2541 No No Memory Corruption Vulnerability CVE-2015-2542 Yes No Scripting Engine Memory Corruption Vulnerability - CVE-2015-2493 A remote code execution vulnerability exists in the way that the VBScript and JScript engines, when rendered in Internet Explorer, handle objects in memory. In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Internet Explorer and then convince a user to view the website. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised websites, and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. The update addresses the vulnerability by modifying how the VBScript and JScript scripting engines handle objects in memory. Microsoft received information about this vulnerability through coordinated vulnerability disclosure. When this security bulletin was originally issued, Microsoft had not received any information to indicate that the vulnerability had been publicly used to attack customers. Elevation of Privilege Vulnerability - CVE-2015-2489 An elevation of privilege vulnerability exists when Internet Explorer does not properly validate permissions under specific conditions, potentially allowing a script to be run with elevated privileges. In a web-based attack scenario, an attacker could host a website that is used to attempt to exploit this vulnerability. In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action. For example, an attacker could trick users into clicking a link that takes them to the attacker's site. An attacker who successfully exploited the vulnerability could elevate privileges in affected versions of Internet Explorer. The vulnerability by itself does not allow arbitrary code to be run. However, the vulnerability could be used in conjunction with another vulnerability (e.g., a remote code execution vulnerability) that could take advantage of the elevated privileges when running arbitrary code. For example, an attacker could exploit another vulnerability to run arbitrary code through Internet Explorer, but due to the context in which processes are launched by Internet Explorer, the code might be restricted to run at a low integrity level (very limited permissions). However, an attacker could, in turn, exploit the vulnerability to cause the arbitrary code to run at a medium integrity level (permissions of the current user). Information Disclosure Vulnerability - CVE-2015-2483 An information disclosure vulnerability exists when Internet Explorer improperly discloses the contents of its memory, which could provide an attacker with information to further compromise the users computer. The update addresses the vulnerability by changing the way certain functions handle objects in memory. Tampering Vulnerability - CVE-2015-2484 A tampering vulnerability exists when Internet Explorer accesses a file with an improper flag that in turn permits a file operation. This could allow a low privilege process to delete arbitrary files on the local system. This update addresses the vulnerability by properly masking this flag off. ========================================================= Serveur de référence du CERT-Renater https://services.renater.fr/ssi/ ========================================================== + CERT-RENATER | tel : 01-53-94-20-44 + + 23 - 25 Rue Daviel | fax : 01-53-94-20-41 + + 75013 Paris | email: cert@support.renater.fr + ==========================================================