J003-Content-PatchTue_SQMicrosoft has been pummeling us with security updates for the past few months, and seemed to be stuck on the number 16 for a while there. While it’s great that they’re fixing all these vulnerabilities, it can put quite a strain on those of us who are tasked with testing and applying them.  The good news is that this time, we get a bit of a reprieve. Don’t get too excited – it’s not like the good old days of Tuesdays Past when we only had to deal with four or five patches, but 11 feels like a fairly light load at this point.

Besides, it’s the middle of July and it’s too hot outside to venture out – at least if you live in the southern part of the United States – so we might as well stay in our air-conditioned buildings and spend the day testing and applying patches. Most of these are for Windows, with the exception of the usual Edge and IE cumulative updates, a Flash Player patch, and one for Office and one for .NET Framework. Six are rated as critical.

Let’s take a look at each of these updates in a little more detail, and you can find the full summary with links to each security bulletin at https://technet.microsoft.com/en-us/library/security/ms16-jul

Critical

MS16-084 (KB 3169991) This is the usual monthly cumulative update for Internet Explorer that applies to IE 9, 10 and 11 (all supported versions) on all supported versions of Windows. It is rated critical for IE 9 and 11 on client operating systems and moderate for IE 9, 10 and 11 on Windows servers, and of course doesn’t apply to server core installations that don’t run a web browser.

The update addresses 15 vulnerabilities, nine of which are capable of remote code execution exploit; the remaining vulnerabilities include spoofing, security feature bypass, and information disclosure issues. Four are memory corruption vulnerabilities in the JScript and VBScript engines while five related to memory corruption issues in IE itself. There are published workarounds for the scripting engine memory corruption vulnerabilities if you’re unable to install the patch; the instructions are published in the security bulletin at https://technet.microsoft.com/library/security/MS16-084, however, there are no workarounds for the rest of these vulnerabilities.

The update fixes the problems by changing how IE and the JScript and VBScript engines handle objects in memory, the way the Microsoft Browser XSS Filter validates JavaScript, and the way IE parses HTML, as well as ensuring that ASLR is properly implemented.

MS16-086 (KB 3169996) This is the usual monthly cumulative update for the Edge web browser running on Windows 10. It is rated critical for Edge running on all editions of Windows 10.

The update addresses 13 vulnerabilities, which include five critical remote code execution issues. The same type of memory corruption vulnerabilities discussed above are included here, as well as spoofing, information disclosure and security feature bypass vulnerabilities.

The update fixes the problems by changing how Edge and the Chakra JavaScript Engine handle objects in memory, the way the Microsoft Browser XSS Filter validates JavaScript, and the way the browser parses HTTP responses and HTML, as well as ensuring that ASLR is properly implemented.

MS16-086 (KB 3169996) This is a cumulative security update for the JScript and VBScript scripting engines in Windows Vista and Server 2008, including the server core installations of Server 2008 and 2008 R2.  It is rated critical on Vista and moderate on Windows Server 2008 and 2008 R2.

The update addresses a single scripting engine memory corruption vulnerability that could be exploited by an attacker to execute arbitrary code through a web-based scenario or by embedding an ActiveX control in an application or Microsoft Office document advertisements. There is a workaround for those who can’t install the update, which is published in the security bulletin at https://technet.microsoft.com/en-us/library/security/ms16-086.aspx

The update fixes the problem by changing the way the JScript and VBScript scripting engines handle objects in memory.

MS16-087 (KB 3170005) This is an update for the Windows Print Spooler components in Windows. It applies to all supported client and server versions of the Windows operating system, including the server core installations, and it is rated critical for all.

The update addresses a pair of vulnerabilities, one of which presents a remote code execution opportunity and the other which is an elevation of privilege issue. To exploit the former, an attacker must be able to create a man-in-the-middle attack or set up a rogue print server on the network. To exploit the latter, the attacker has to be able to log onto the affected system and run a malicious script or application. The RCE vulnerability is critical and the EoP vulnerability is important.

The update fixes both problems by changing the way the Print Spooler service writes to the file system and issuing a warning to users who attempt to install untrusted printer drivers.

MS16-088 (KB 3170008) This is an update for Microsoft Office. It affects Office 2007, 2010, 2013, 2013 RT, 2016, Office for Mac 2011, the Compatibility Pack SP3, Word Viewer, Excel Viewer, SharePoint Server 2010, 2013 and 2016, Office Web Apps 2010 and 2013, and Office Online Server.  It is rated critical for the Office software suites and important for the other products.

The update addresses six memory corruption vulnerabilities that can be exploited to run arbitrary code by convincing a user to open a specially crafted email attachment or by hosting a website that downloads the malicious file. The update also addresses a remote code execution vulnerability that is caused by Office’s improper handling of XLA files.

The update fixes the problems by changing the way Office and certain functions handle objects in memory and the way Windows validates input from loading libraries.

MS16-093 (KB 3174060) This is an update for Adobe Flash Player on Windows 8.1, RT 8.1 and Windows 10, as well as Server 2012 and 2012 R2, excluding the server core installations. It is rated critical for the client operating systems and important for the server operating systems.

The update addresses 24 vulnerabilities in Flash Player, which include multiple memory corruption issues along with other remote code execution vulnerabilities that could be exploited through web-based attacks or by embedding malicious content in applications or Microsoft Office documents that host the IE rendering engine. There is a workaround published in the security bulletin at https://technet.microsoft.com/en-us/library/security/ms16-093.aspx

The update fixes the problem by changing the handling of objects in memory and correcting the other flaws in Flash Player.

Important

MS16-089 (KB 3170050) This is an update to the Windows Secure Kernel Mode. It affects all supported releases of Windows 10 and is rated important.

The update addresses a single information disclosure vulnerability by which a locally authenticated attacker could potentially read sensitive information on the target system by running a specially crafted application.

The update fixes the problem by changing the way Windows Secure Kernel Mode handles objects in memory.

MS16-090 (KB 3171481) This is an update for the Windows Kernel-Mode drivers. It affects all supported client and server versions of the Windows operating system, including the server core installations, and it is rated important for all.

The update addresses five separate elevation of privilege vulnerabilities that are caused by the way the Windows kernel-mode drivers handle objects in memory, and could be exploited to run arbitrary code in kernel mode; however, the attacker would have to be able to first log onto the system and run a specially crafted application. The update also addresses a single Win32k information disclosure vulnerability caused by improper disclosure of kernel memory addresses by the Windows GDI.

The update fixes the problems by changing the way the Windows kernel-mode driver and the Windows GDI component handle objects in memory.

MS16-091 (KB 3170048) This is an update for the Microsoft .NET Framework, which affects .NET Framework 2.0 Service Pack 2, Microsoft .NET Framework 3.5, Microsoft .NET Framework 3.5.1, Microsoft .NET Framework 4.5.2, Microsoft .NET Framework 4.6, and Microsoft .NET Framework 4.6.1 on all supported versions of Windows client and server operating systems, including the server core installations. It is rated important for all.

The update addresses a single information disclosure vulnerability that is caused by improper parsing of XML input that contains a reference to an external entity, by the .NET Framework. This could be exploited to read arbitrary files.

The update fixes the problem by changing the way the XML External Entity (XEE) parser parses XML input.

MS16-092 (KB 3171910) This is an update for the Windows kernel. It affects supported versions of Windows 8.1, RT 8.1 and Windows 10, as well as Windows Server 2012 and 2012 R2, including the server core installation. It is rated important for all.

The update addresses two vulnerabilities in the kernel. One is a Windows file system security feature bypass that an attacker could use to make changes to files, by exploiting Time Of Check Time Of Use issues. The other is an information disclosure issue that is caused by improper handling of page fault system calls by the Windows kernel. In order to exploit it, the attacker would have to be able to log onto the system or convince a logged-on user to run a malicious application.

The update fixes the problem by adding a validation check on how long a low integrity application can use certain object manager features and changing the way the kernel handles certain page fault system calls.

MS16-094 (KB 3177404) This is an update for the Secure Boot component of Windows and applies to Windows 8.1, RT 8.1 and Windows 10, as well as Server 2012 and 2012 R2, including the server core installation. It is rated important for all.

The update addresses a single vulnerability in Windows Secure Boot which occurs when an affected policy is improperly applied. This could be exploited to bypass the security feature and disable code integrity checks, as well as bypassing the Secure Boot integrity validation for BitLocker and the Device Encryption security features. To carry out the exploit, the attacker would have to be able to get admin privileges or physical access to the targeted device. There are workarounds published in the security bulletin at https://technet.microsoft.com/en-us/library/security/ms16-094.aspx

The update fixes the problem by blacklisting affected policies.