Tag Archives: Linux Kernel Module

April 2019 Update Summary

Yesterday Microsoft and Adobe made available their scheduled security updates. Microsoft addressed 74 vulnerabilities (more formally known as CVEs (defined)) with Adobe resolving 42 vulnerabilities.

Adobe Acrobat and Reader: 21x priority 2 vulnerabilities (11x Critical and 10x Important severity)

Adobe Flash: 2x priority 2 vulnerabilities (1x Critical and 1x Important severity)

Adobe Shockwave Player: 7x priority 2 vulnerabilities (7x Critical severity)

Adobe Dreamweaver: 1x priority 3 vulnerability (Moderate severity)

Adobe XD: 2x priority 3 vulnerabilities (2x Critical severity)

Adobe InDesign: 1x priority 3 vulnerability (Critical severity)

Adobe Experience Manager Forms: 1x priority 2 vulnerability (Important severity)

Adobe Bridge CC: 8x priority CVEs (2x Critical, 6x Important)

If you use Acrobat/Reader, Flash or Shockwave, please apply the necessary updates as soon as possible. Please install their remaining priority 2 and 3 updates when you can.

Please note; as per Adobe’s notice Shockwave Player has now reached it’s end of life. No further updates will be made available.

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For Microsoft; this month’s list of Known Issues is available within their monthly summary page and applies to all currently supported operating systems. All issues however do have at least 1 workaround:

4487563                Microsoft Exchange Server 2019, 2016, and 2013

4491413                Update Rollup 27 for Exchange Server 2010 Service Pack 3

4493441                Windows 10 version 1709, Windows Server Version 1709

4493446                Windows 8.1, Windows Server 2012 R2 (Monthly Rollup)

4493448                Windows 7 Service Pack 1, Windows Server 2008 R2 Service Pack 1 (Security-only update)

4493450                Windows Server 2012 (Security-only Rollup)

4493451                Windows Server 2012 (Monthly Rollup)

4493458                Windows Server 2008 Service Pack 2 (Security-only update)

4493464                Windows 10 version 1803, Windows Server Version 1803

4493467                Windows 8.1, Windows Server 2012 R2 (Security-only update)

4493470                Windows 10 version 1607, Windows Server 2016

4493471                Windows Server 2008 Service Pack 2 (Monthly Rollup)

4493472                Windows 7 Service Pack 1, Windows Server 2008 R2 Service Pack 1 (Monthly Rollup)

4493474                Windows 10 version 1703

4493509                Windows 10 version 1809, Windows Server 2019

4493730                Windows Server 2008 SP2

4493435                Internet Explorer Cumulative Update

You can monitor the availability of security updates for most your software from the following websites (among others) or use one of the utilities presented on this page:

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US Computer Emergency Readiness Team (CERT) (please see the “Information on Security Updates” heading of the “Protecting Your PC” page):

https://www.us-cert.gov/

A further useful source of update related information is the Calendar of Updates.

News/announcements of updates in the categories of General SoftwareSecurity Software and Utilities are available on their website. The news/announcements are very timely and (almost always) contain useful direct download links as well as the changes/improvements made by those updates (where possible).

If you like and use it, please also consider supporting that entirely volunteer run website by donating.

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For this month’s Microsoft updates, I will prioritize the order of installation below:
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Win32k: CVE-2019-0803CVE-2019-0859 (both are being actively exploited in the wild)

Scripting Engine: CVE-2019-0861 ,  CVE-2019-0806 , CVE-2019-0739 , CVE-2019-0812 , CVE-2019-0829

Microsoft Graphics Component (GDI+): CVE-2019-0853

Microsoft Windows IOleCvt Interface: CVE-2019-0845

Microsoft Windows SMB Server: CVE-2019-0786

Microsoft (MS) XML: CVE-2019-0790 , CVE-2019-0791 , CVE-2019-0792 , CVE-2019-0793 , CVE-2019-0795

Microsoft Edge and Internet Explorer (multiple versions of Edge and IE affected)

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Please install the remaining updates at your earliest convenience.

As per standard best practice; I would recommend backing up the data on any device for which you are installing updates to prevent data loss in the rare event that any update causes unexpected issues. I have provided further details of updates available for other commonly used applications below.

Thank you.

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Notepad++:
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As noted in the March Update Summary post (due to a critical regression for the version that was released in March) Notepad++ 7.6.6 was released to resolve a critical regression in 7.6.5 which caused Notepad++ to crash. Version 7.6.5 resolved a further 6 security vulnerabilities.

If you use Notepad++, please update to the newest version to benefit from these reliability and security fixes.

Thank you.

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Wireshark 3.0.1 and 2.6.8
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v3.0.1: 10 security advisories

v2.6.8: 6 security advisories

As per standard process Linux distributions can obtain this update using the operating systems standard package manager (if the latest version is not installed automatically using the package manager you can instead compile the source code (v3.0.1 or v2.6.8). This forum thread and this forum thread may also be helpful to you with installing Wireshark on your Linux based system.

For Mac OS X and Windows, the update is available within the downloads section of the Wireshark website. In addition, a detailed FAQ for Wireshark is available here.

Oracle VirtualBox Zero Day Disclosed

In early November a security researcher publicly disclosed (defined) a zero day (defined) vulnerability within Oracle’s VirtualBox virtualisation software.

How severe is this vulnerability?
In summary; this vulnerability is serious but it could have been worse. In order to exploit it, an attacker would first need to have obtained elevated privileges on your system; root (defined) in the case of Linux and administrator (defined) in the case of Windows. Using this privilege the attacker can leverage the exploit to escape from the confines of the virtual machine (VM)(defined) into the system which hosts the virtual machine (in other words; the system which houses the virtual machine within its physical infrastructure). Once outside of the virtual machine the attacker must then elevate their privileges again since breaking out of the VM only gives them user level/standard privileges and not elevated privileges in the physical system. Thus the attacker would then need to use a separate exploit for another vulnerability (not related to this VirtualBox flaw) to elevate their privileges again to become root/admin within the physical system.

Obviously; the consequences of exploiting this vulnerability on a shared service/cloud infrastructure system would be more serious since multiple users would be affected all at once and the further exploitation of the resulting host systems could potentially provide the attacker with control over all the virtual machines.

How can an attacker exploit this vulnerability?
VirtualBox makes use of the Intel Pro/1000 MT Desktop (82540EM) network adapter to provide an internet connection to the virtual machines it manages. The attacker must first turn off this adapter in the guest (virtualised) operating system. Once complete they can then load a custom Linux kernel module (LKM)(defined) (this does not require a reboot of the system). That custom LKM contains the exploit derived from the technical write up provided. That new LKM loads its own custom version of the Intel network adapter. Next the LKM exploits a buffer overflow (defined) vulnerability within the virtualised adapter to escape the guest operating system. The attack must then unload the custom LKM to re-enable the real Intel adapter to resume their access to the internet.

How can I protect myself from this vulnerability?
While this is a complex vulnerability to exploit (an attacker would need to chain exploits together in order to elevate their privilege on the host system after escaping the VM), the source code needed to do so is available in full from the researcher’s disclosure; increasing the risk of it being used by attackers.

At the time of writing; this vulnerability has not yet been patched by VirtualBox. It affects versions 5.2.20 and earlier when installed on Ubuntu version 16.04 and 18.04 x86-64 guests (Windows is believed to be affected too). While a patch is pending; you can change the network card type to PCnet or Para virtualised Network. If this isn’t an option available or convenient for you; you can an alternative to the NAT mode of operation for the network card.

Thank you.