==================================================================== CERT-Renater Note d'Information No. 2017/VULN061 _____________________________________________________________________ DATE : 15/03/2017 HARDWARE PLATFORM(S): / OPERATING SYSTEM(S): Systems running Internet Explorer versions 11, 10, 9. ===================================================================== KB4013073 https://technet.microsoft.com/en-us/library/security/MS17-006 ____________________________________________________________________ MS17-006: Cumulative Security Update for Internet Explorer (4013073) Critical Bulletin Number: MS17-006 Bulletin Title: Cumulative Security Update for Internet Explorer Severity: Critical KB Article: 4013073 Version: 1.0 Published Date: 14/03/2017 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. If the current user is logged on with administrative user rights, an attacker who successfully exploited this 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. This security update is rated Critical for Internet Explorer 9 (IE 9) and Internet Explorer 11 (IE 11) on affected Windows clients, and Moderate for 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. For more information about the vulnerabilities, see the Vulnerability Information section. For more information about this update, see Microsoft Knowledge Base Article 4013073. Affected Software Internet Explorer 9 Internet Explorer 10 Internet Explorer 11 Update FAQ In addition to installing this update are there any further steps I need to carry out to be protected from any of the vulnerabilities discussed in this bulletin? Yes. For Vista and Windows Server 2008 operating systems installing the 4012204 cumulative update by itself does not fully protect against CVE-2017-0008 you must also install security update 3218362 in MS17-006 to be fully protected from the vulnerability. Vulnerability Information Multiple Information Disclosure Vulnerabilities Information disclosure vulnerabilities exist in the way that the affected components handle objects in memory. An attacker who successfully exploited these vulnerabilities could obtain information to further compromise a target system. In a web-based attack scenario an attacker could host a website in an attempt to exploit the vulnerabilities. Additionally, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could be used to exploit the vulnerabilities. However, in all cases an attacker would have no way to force users to view 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. The security update addresses the vulnerabilities by correcting how the affected components handle objects in memory. Mitigating Factors Microsoft has not identified any mitigating factors for these vulnerabilities. Workarounds Microsoft has not identified any workarounds for these vulnerabilities. Multiple Microsoft Browser Memory Corruption Vulnerabilities Multiple remote code execution vulnerabilities exist when affected Microsoft browsers improperly access 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 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, the attacker 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. An attacker could host a specially crafted website that is designed to exploit these vulnerabilities through affected Microsoft browsers, and then convince a user to view the website. The attacker could also take advantage of compromised websites, or websites that accept or host user-provided content or advertisements, by adding specially crafted content that could exploit the 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, typically by an enticement in an email or Instant Messenger message, or by getting them to open an attachment sent through email. The update addresses these vulnerabilities by modifying how Microsoft browsers handle objects in memory. Mitigating Factors Microsoft has not identified any mitigating factors for these vulnerabilities. Workarounds Microsoft has not identified any workarounds for these vulnerabilities. FAQ I am running Internet Explorer on Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, or Windows Server 2012 R2. Does this mitigate these vulnerabilities? Yes. By default, Internet Explorer on Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, and Windows Server 2012 R2 runs in a restricted mode that is known as Enhanced Security Configuration. Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted web content on a server. This is a mitigating factor for websites that you have not added to the Internet Explorer Trusted sites zone. Can EMET help mitigate attacks that attempt to exploit these vulnerabilities? Yes. The Enhanced Mitigation Experience Toolkit (EMET) enables users to manage security mitigation technologies that help make it more difficult for attackers to exploit memory corruption vulnerabilities in a given piece of software. EMET can help mitigate attacks that attempt to exploit these vulnerabilities in Internet Explorer on systems where EMET is installed and configured to work with Internet Explorer. For more information about EMET, see the Enhanced Mitigation Experience Toolkit. Multiple Microsoft Browser Spoofing Vulnerabilities Spoofing vulnerabilities exist when a Microsoft browser does not properly parse HTTP responses. An attacker who successfully exploited these vulnerabilities could trick a user by redirecting them to a specially crafted website. The specially crafted website could spoof content or be used as a pivot to chain an attack with other vulnerabilities in web services. To exploit these vulnerabilities, the user must click a specially crafted URL. In an email attack scenario, an attacker could send an email message containing the specially crafted URL to the user in an attempt to convince the user to click it. In a web-based attack scenario, an attacker could host a specially crafted website designed to appear as a legitimate website to the user. However, the attacker would have no way to force the user to visit the specially crafted website. The attacker would have to convince the user to visit the specially crafted website, typically by way of enticement in an email or Instant Messenger message, and then convince the user to interact with content on the website. The update addresses the vulnerabilities by correcting how Microsoft browsers parse HTTP responses. Mitigating Factors Microsoft has not identified any mitigating factors for these vulnerabilities. Workarounds Microsoft has not identified any workarounds for these vulnerabilities. Multiple Scripting Engine Memory Corruption Vulnerabilities Multiple remote code execution vulnerabilities exist in the way that the JScript and VBScript engines render when handling objects in memory in Internet Explorer. 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 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. In a web-based attack scenario, 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. 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 these vulnerabilities. The update addresses these vulnerabilities by modifying how the JScript and VBScript scripting engines handle objects in memory. Mitigating Factors Microsoft has not identified any mitigating factors for these vulnerabilities. Workarounds Microsoft has not identified any workarounds for these vulnerabilities. Scripting Engine Information Disclosure Vulnerability - CVE-2017-0049 An information disclosure vulnerability exists when the Jscript scripting engine does not properly handle objects in memory. The vulnerability could allow an attacker to detect specific files on the user's computer. In a web-based attack scenario, an attacker could host a website that is used to attempt to exploit the vulnerability. In addition, compromised websites and websites that accept or host user-generated content could contain specially crafted content that could exploit the vulnerability. In all cases, however, an attacker would have no way to force a user 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 potentially read data that was not intended to be disclosed. Note that the vulnerability would not allow an attacker to execute code or to elevate a users rights directly, but the vulnerability could be used to obtain information in an attempt to further compromise the affected system. The security update addresses the vulnerability by helping to restrict what information is returned to affected Microsoft browsers. Mitigating Factors Microsoft has not identified any mitigating factors for this vulnerability. Workarounds Microsoft has not identified any workarounds for this vulnerability. Internet Explorer Elevation of Privilege Vulnerability - CVE-2017-0154 An elevation of privilege vulnerability exists when Internet Explorer does not properly enforce cross-domain policies, which could allow an attacker to access information from one domain and inject it into another domain. The update addresses the vulnerability by helping to ensure that cross-domain policies are properly enforced in Internet Explorer. In a web-based attack scenario, an attacker could host a website that is used to attempt to exploit the vulnerability. In addition, compromised websites and websites that accept or host user-provided content could contain specially crafted content that could exploit the 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 this 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 (for example, 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 this vulnerability to cause the arbitrary code to run at a medium integrity level (permissions of the current user). Mitigating Factors Microsoft has not identified any mitigating factors for this vulnerability. Workarounds Microsoft has not identified any workarounds for this vulnerability. Security Update Deployment For Security Update Deployment information see the Microsoft Knowledge Base article referenced here in the Executive Summary. Acknowledgments Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgments for more information. 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. ========================================================== 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 + ==========================================================