August 2018 Microsoft Patch Tuesday fixes two flaws exploited in attacks in the wild

Microsoft Patch Tuesday update for August 2018 addresses a total of 60 vulnerabilities, two of which are actively exploited in attacks in the wild.

After Adobe, also Microsoft released the Patch Tuesday update for August 2018 that addresses a total of 60 vulnerabilities in Microsoft Windows, Edge Browser, Internet Explorer, Office, ChakraCore, .NET Framework, Exchange Server, Microsoft SQL Server and Visual Studio.

19 remote code execution vulnerabilities are rated as critical and two flaws are being exploited in the wild at the time of release.

Microsoft has also addressed 39 important vulnerabilities, one moderate and one low in severity.

Let’s start with the vulnerabilities exploited in attacks in the wild:

CVE-2018-8373 – IE Scripting Engine Memory Corruption Vulnerability

The vulnerability affects Internet Explorer 9, 10 and 11, it was first disclosed last month by Trend Micro and affected all supported versions of Windows.

The flaw could be exploited by remote attackers to take control of the vulnerable systems by tricking victims into viewing a specially crafted website through Internet Explorer. The attacker could also embed an ActiveX control marked ‘safe for initialization’ in an application or Microsoft Office document that hosts the IE rendering engine.

“A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer. The vulnerability could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user.” reads the security advisory published by Microsoft.

“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.”

CVE-2018-8414 – Windows Shell Remote Code Execution Vulnerability

The flaw is actively exploited in attacks in the wild, it resides in the Windows Shell and tied with the improper validation of file paths. An attacker can execute arbitrary code on the vulnerable system by tricking victims into opening a specially crafted file received via an email or a web page.

“An attacker who successfully exploited this vulnerability could run arbitrary code in the context of the current user. If the current user is logged on as an administrator, an attacker could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with elevated privileges. Users whose accounts are configured to have fewer privileges on the system could be less impacted than users who operate with administrative privileges.” states the advisory.

“To exploit the vulnerability, an attacker must entice a user to open a specially crafted file. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and then convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) that contains a specially crafted file designed to exploit the vulnerability. An attacker would have no way to force a user to visit the website. Instead, an attacker would have to convince a user to click a link and open the specially crafted file.”

Below the description for some of the RCE flaws addressed by Microsoft

CVE-2018-8273 – Microsoft SQL Server RCE

A buffer overflow vulnerability affects Microsoft SQL Server 2016 and 2017, a remote attacker could exploit it to execute arbitrary code on an affected system in the context of the SQL Server Database Engine service account.

“A buffer overflow vulnerability exists in the Microsoft SQL Server that could allow remote code execution on an affected system. An attacker who successfully exploited this vulnerability could execute code in the context of the SQL Server Database Engine service account.” states the advisory.

“To exploit the vulnerability, an attacker would need to submit a specially crafted query to an affected SQL server.

The security update addresses the vulnerability by modifying how the Microsoft SQL Server Database Engine handles objects in memory.”

CVE-2018-8350 – Windows PDF Remote Code Execution Vulnerability

Microsoft Edge running as default browser on Windows 10 systems can be compromised by tricking users to view a specially crafted website.

The issue tied with the improper handling of the objects in the memory, Windows 10’s PDF library could be exploited by a remote attacker to execute arbitrary code on the targeted system.

“A remote code execution vulnerability exists when Microsoft Windows PDF Library improperly handles objects in memory. The vulnerability could corrupt memory in a way that enables an attacker to execute arbitrary code in the context of the current user.” states the advisory.

“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 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 list of flaws addressed by Microsoft includes:

• Microsoft Exchange Memory Corruption Vulnerability (CVE-2018-8302)
• Microsoft Graphics Remote Code Execution Vulnerability (CVE-2018-8344)
• LNK Remote Code Execution Vulnerability (CVE-2018-8345)
• GDI+ Remote Code Execution Vulnerability (CVE-2018-8397)

Pierluigi Paganini

(Security Affairs – Microsoft Patch Tuesday , hacking)

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