Tuesday, October 9, 2018

Microsoft Patch Tuesday — October 18: Vulnerability disclosures and Snort coverage

Microsoft released its monthly security update today, disclosing a variety of vulnerabilities in several of its products. The latest Patch Tuesday covers 49 vulnerabilities, 12 of which are rated "critical," 34 that are rated "important,” two that are considered to have “moderate” severity and one that’s rated as “low.”

The advisories cover bugs in the Chakra scripting engine, the Microsoft Edge internet browser and the Microsoft Office suite of products, among other software.

This update also includes a critical advisory that covers updates to the Microsoft Office suite of products.

Please visit the SNORTⓇ blog here if you would like to know more about the coverage we have for these vulnerabilities.
Critical vulnerabilities

Microsoft has disclosed 12 critical vulnerabilities this month, which we will highlight below.

CVE-2018-8491, CVE-2018-8460 and CVE-2018-8509 are memory corruption vulnerabilities in the Internet Explorer web browser. In both cases, an attacker needs to trick the user into visiting a specially crafted, malicious website that can corrupt the browser’s memory, allowing for remote code execution in the context of the current user. This class of vulnerabilities is especially dangerous since a spam campaign can be used to trick the user while hiding the attack from network protections with HTTPS.

CVE-2018-8473 is a remote code execution vulnerability in Microsoft Edge. The bug lies in the way the web browser accesses objects in memory. An attacker could trick a user into visiting a malicious website or take advantage of a website that accepts user-created content or advertisements in order to exploit this vulnerability.

CVE-2018-8513, CVE-2018-8500, CVE-2018-8511, CVE-2018-8505 and CVE-2018-8510 are memory corruption vulnerabilities in the Chakra scripting engine that affects a variety of products. In all cases, an attacker could exploit these vulnerabilities to execute code on the system in the context of the current user and completely take over the system. This class of vulnerabilities is especially dangerous since a spam campaign can be used to trick the user while hiding the attack from network protections with HTTPS.

CVE-2018-8494 is a remote code execution vulnerability that exists when the MSXML parser in Microsoft XML Core Services processes user input. An attacker can exploit this bug by invoking MSXML through a web browser on a specially crafted website. The user also needs to convince the user to open the web page.

CVE-2018-8490 and CVE-2018-8489 are remote code execution vulnerabilities in the Windows Hyper-V hypervisor. The bugs lie in the way the host server on Hyper-V fails to properly validate input from an authenticated user on a guest operating system. An attacker could exploit these vulnerabilities by running a specially crafted application on a guest operating system that could cause the Hyper-V host operating system to execute arbitrary code.

Important vulnerabilities

There are also 34 important vulnerabilities in this release. We would like to specifically highlight 22 of them.

CVE-2018-8512 is a security feature bypass vulnerability in Microsoft Edge. The web browser improperly validates certain specially crafted documents in the Edge Content Security Policy (CSP), which could allow an attacker to trick a user into loading a malicious page.

CVE-2018-8448 is an elevation of privilege vulnerability in the Microsoft Exchange email server. The bug exists in the way that Exchange Outlook Web Access improperly handles web requests. An attacker could exploit this vulnerability by performing script or content injection attacks that trick the user into disclosing sensitive information. They could also trick the user into providing login credentials via social engineering in an email or chat client.

CVE-2018-8453 is an elevation of privilege vulnerability in the Windows operating system that occurs when the Win32k component improperly handles objects in memory. An attacker could obtain the ability to run arbitrary code in kernel mode by logging onto the system and then run a specially crafted application.

CVE-2018-8484 is an elevation of privilege vulnerability in the DirectX Graphics Kernel driver that exists when the driver improperly handles objects in memory. An attacker could log onto the system and execute a specially crafted application to exploit this bug and run processes in an elevated context.

CVE-2018-8423 is a remote code execution vulnerability in the Microsoft JET Database Engine that could allow an attacker to take control of an affected system. A user must open or import a specially crafted Microsoft JET Database Engine file on the system in order to exploit this bug. They could also trick a user into opening a malicious file via email.

CVE-2018-8502 is a security feature bypass vulnerability in Microsoft Excel when the software fails to properly handle objects in protected view. An attacker could execute arbitrary code in the context of the current user if they convince the user to open a specially crafted, malicious Excel document via email or on a web page. This bug cannot be exploited if the user opens the Excel file in just the preview pane.

CVE-2018-8501 is a security feature bypass vulnerability in Microsoft PowerPoint. The bug exists when the software improperly handles objects in protected view. An attacker can execute arbitrary code in the context of the current user if they convince the user to open a specially crafted PowerPoint file. This bug cannot be exploited if the user only opens the file in preview mode.

CVE-2018-8432 is a remote code execution vulnerability that lies in the way Microsoft Graphics Components handles objects in memory. A user would have to open a specially crafted file in order to trigger this bug.

CVE-2018-8504 is a security feature bypass vulnerability in the Microsoft Word word processor. There is a flaw in the way the software handles objects in protected view. An attacker could obtain the ability to arbitrarily execute code in the context of the current user if they convince the user to open a malicious Word document. The bug cannot be triggered if the user opens the file in preview mode.

CVE-2018-8427 is an information disclosure vulnerability in Microsoft Graphics Components. An attacker could exploit this vulnerability by tricking the user into opening a specially crafted file, which would expose memory layout.

CVE-2018-8480 is an elevation of privilege vulnerability in the Microsoft SharePoint collaborative platform. The bug lies in the way the software improperly sanitizes a specially crafted web request to an affected SharePoint server. An attacker could exploit this vulnerability by sending a specially crafted request to an affected SharePoint server.

CVE-2018-8518, CVE-2018-8488 and CVE-2018-8498 are elevation of privilege vulnerabilities in the Microsoft SharePoint Server. An attacker can exploit these bugs by sending a specially crafted request to an affected SharePoint server, allowing them to carry out cross-site scripting attacks and execute code in the context of the current user.

CVE-2018-8333 is an elevation of privilege vulnerability in Filter Management that exists when the program improperly handles objects in memory. An attacker needs to log onto the system and delete a specially crafted file in order to exploit this bug, which could lead to them gaining the ability to execute code in the context of an elevated user.

CVE-2018-8411 is an elevation of privilege vulnerability that exists when the NFTS file system improperly checks access. An attacker needs to log onto the system to exploit this bug and then run a specially crafted application, which could lead to the attacker running processes in an elevated context.

CVE-2018-8320 is a security feature bypass vulnerability that exists in the DNS Global Blocklist feature. An attacker who exploits this bug could redirect traffic to a malicious DNS endpoint.

CVE-2018-8492 is a security bypass vulnerability in the Device Guard Windows feature that could allow an attacker to inject malicious code into Windows PowerShell. An attacker needs direct access to the machine in order to exploit this bug, and then inject malicious code into a script that is trusted by the Code Integrity policy. The malicious code would then run with the same access level as the script, and bypass the integrity policy.

CVE-2018-8329 is an elevation of privilege vulnerability in Linux on Windows. The bug lies in the way Linux improperly handles objects in memory. An attacker can completely take control of an affected system after logging onto the system and running a specially crafted application.

CVE-2018-8497 is an elevation of privilege vulnerability that exists in the way the Windows Kernel handles objects in memory. A locally authenticated attacker can exploit this bug by running a specially crafted application.

CVE-2018-8495 is a remote code execution vulnerability that exists in the way Windows Shell handles URIs. An attacker needs to convince the user to visit a specially crafted website on Microsoft Edge in order to exploit this vulnerability.

CVE-2018-8413 is a remote code execution vulnerability that exists when “Windows Theme API” improperly decompresses files. A victim can exploit this bug by convincing the user to open a specially crafted file via an email, chat client message or on a malicious web page, allowing the attacker to execute code in the context of the current user.

Other important vulnerabilities:

Moderate vulnerabilities

Of the two moderate vulnerabilities disclosed by Microsoft, Talos believes one is worth highlighting.

CVE-2010-3190 is a remote code execution vulnerability in the way that certain applications built using Microsoft Foundation Classes handle the loading of DLL files. An attacker could take complete control of an affected system by exploiting this vulnerability. At the time this bug was first disclosed, Exchange Server was not identified as an in-scope product, which is why this release highlights a flaw from 2010.

The other moderate vulnerability is CVE-2018-8533.

Low vulnerability

There is also one low-rated vulnerability, which Talos wishes to highlight.

CVE-2018-8503 is a remote code execution vulnerability in the way that Chakra scripting engine handles objects in memory in the Microsoft Edge web browser. An attacker needs to convince a user to visit a malicious website or malicious content on a web page that allows user-created content or advertisements in order to exploit this bug.

Coverage

In response to these vulnerability disclosures, Talos is releasing the following Snort rules that detect attempts to exploit them. Please note that additional rules may be released at a future date and current rules are subject to change pending additional information. Firepower customers should use the latest update to their ruleset by updating their SRU. Open Source Snort Subscriber Rule Set customers can stay up-to-date by downloading the latest rule pack available for purchase on Snort.org.

Snort rules: 48045 - 48057, 48058 - 48060, 48062, 48063, 48072, 48073

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