Tag Archives: Zero Day

December 2018 Update Summary

Earlier today Microsoft and Adobe made available monthly updates addressing 39 vulnerabilities and 88 vulnerabilities (more formally known as CVEs (defined)) respectively. As always; more information is available from Microsoft’s monthly summary page and Adobe’s blog post.

While Adobe’s update addresses a large number of vulnerabilities; Microsoft’s released updates are fewer in overall vulnerabilities and should be considered light when compared to some months this year. If you use Adobe Flash Player, if you have not already done so; please ensure it is up to date (version 32.0.0.101). They addressed a zero day (defined) vulnerability with that update earlier this month which was in use by an APT group (defined in this context it is an organised group making use of zero day vulnerabilities).

Unfortunately; Microsoft’s updates also come with a list of Known Issues that will be resolved in future updates. They are listed below for your reference:

KB4471318: Windows 7 SP1 and Windows Server 2008 R2 SP1 : Workaround provided

KB4471321 : Windows 10, Version 1607Windows Server 2016 : resolutions are in progress

KB4471324 Windows 10, Version 1803 : resolution in progress

KB4471327 : Windows 10, Version 1703 : resolution in progress

KB4471329 Windows 10, Version 1709 : resolution in progress

As briefly mentioned above Adobe issued updates for Adobe Acrobat and Reader:

Adobe Acrobat and ReaderPriority 2: Resolves 40x Critical CVEs ands 48x Important CVEs

If you use Adobe Acrobat or Reader, please update it as soon as possible especially given the large number of critical vulnerabilities that were patched.

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:

====================
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.

====================
For this month’s Microsoft updates, I will prioritize the order of installation below:
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Microsoft Edge and Internet Explorer (multiple versions of Edge and IE affected)

CVE-2018-8611 : Windows Kernel (defined) (this vulnerability is already being exploited)

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Please install the remaining updates at your earliest convenience.

As usual; 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.

Please find below summaries of other notable updates released this month.

Thank you.

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Mozilla Firefox
=======================
Also earlier today Mozilla made available security updates for Firefox and Firefox ESR (Extended Support Release):

Firefox 64: Resolves 2x critical CVEs (defined), 5x high CVEs, 3x moderate CVEs and 1x low CVE

Firefox ESR 60.4: Resolves 1x critical CVE, 4x high CVEs and 1x low CVE.

Further details of the security issues resolved by these updates are available in the links above. Details of how to install updates for Firefox are here. If Firefox is your web browser of choice, if you have not already done so, please update it as soon as possible to resolve these security issues.

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Google Chrome:
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Google released Google Chrome version 71.0.3578.80 to address 43 vulnerabilities.

Google Chrome updates automatically and will apply the update the next time Chrome is closed and then re-opened. Chrome can also be updated immediately by clicking the Options button (it looks like 3 stacked small horizontal lines, sometimes called a “hamburger” button) in the upper right corner of the window and choosing “About Google Chrome” from the menu. Follow the prompt to Re-launch Chrome for the updates to take effect.

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.

November 2018 Update Summary

Yesterday Microsoft and Adobe published their routine monthly updates resolving 62 and 3 vulnerabilities (more formally known as CVEs (defined)) respectively. More information is available from Microsoft’s monthly summary page and Adobe’s blog post.

Microsoft’s updates also come with a list of Known Issues that will be resolved in future updates. They are listed below for your reference:

KB4467691

KB4467696

KB4467686

KB4467702 (file type association issue to be resolved later in November 2018)

KB4467107

As summarized above; Adobe issued 3 updates for the following products:

Adobe Acrobat and Reader: Priority 1: Resolves 1x Important CVE (see also this page for a Windows 10 additional mitigation)

Adobe Flash Player: Priority 2: Resolves 1x Important CVE

Adobe Photoshop CC: Priority 3: Resolves 1x Important CVE

As per standard practice if you use any of the above Adobe software, please update it as soon as possible especially in the case of Acrobat DC and Reader DC due to the public proof of concept code released.

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:

====================
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.

====================
For this month’s Microsoft updates, I will prioritize the order of installation below:
====================
Microsoft Edge and Internet Explorer (multiple versions of Edge and IE affected)

Windows Kernel (a zero day (defined) vulnerability in Windows Server 2008, Server 2008 R2 and Windows 7)

Microsoft Dynamics 365

Windows Deployment Services (if used within your organization)

Microsoft Office (11x CVEs + 3x further CVEs in Office SharePoint)

Windows VBScript

Microsoft Graphics Component

Microsoft Bitlocker

====================
Please install the remaining updates at your earliest convenience.

As usual; 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.

Please find below summaries of other notable updates released this month.

Thank you.

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Nvidia Graphics Drivers:
=======================
A low severity vulnerability (this is a local rather than a remotely exploitable vulnerability) with a CVSS V3 (defined) base score 2.2 had been found within Nvidia’s graphics card drivers (defined). At the time of writing no fix is yet available but will address it in a future driver release. Please monitor their security advisory for further updates.

Windows Data Sharing Service Zero Day Disclosed

In late October, a new Windows zero day vulnerability (defined) was publicly disclosed (defined) by the security researcher SandboxEscaper (the same researcher who disclosed the Task Scheduler zero day in early September. This vulnerability affects a Windows service; Data Sharing Service (dssvc.dll) present in Windows 10 and its Server equivalents 2016 and 2019. Windows 8.1 and Windows 7 (and their Server equivalents (Windows Server 2008 R2, Windows Server 2012 R2) are not affected.

How severe is this vulnerability and what is its impact?
Similar to the Task Scheduler vulnerability; this vulnerability is not remotely exploitable by an attacker (more on this below). This vulnerability should be considered medium but not critical severity. When exploited it can allow an attacker to delete any files they choose since they will inherit the same level of permission (privilege escalation)(defined) as the Data Sharing Service namely LocalSystem privileges (the highest level of privilege)(defined) but they cannot initiate this automatically/remotely. They must socially engineer a potential victim into opening an attachment (most likely sent over email or via instant messaging etc.).

As with the Task Scheduler vulnerability; this vulnerability may be leveraged in the wild before it is patched by Microsoft; this is my reason for advising exercising caution with email and clicking unexpected links.

While security researchers such as Will Dorman (mentioned above) and Kevin Beaumont were successful in verifying the proof of concept code worked. They class the vulnerability difficult to exploit. This was verified by Acros Security CEO Mitja Kolsek noting he could not find a “generic way to exploit this for arbitrary code execution.” Indeed, SandboxEscaper described the vulnerability as a low quality bug (making it a “pain” to exploit). Tom Parson’s from Tenable (the vendor of the Nessus vulnerability scanner) summed it nicely stating “to put the threat into perspective, an attacker would already need access to the system or to combine it with a remote exploit to leverage the vulnerability”.

The vulnerability may allow the attacker to perform DLL hijacking (defined) by deleting key system DLLs (defined) and then replacing them with malicious versions (by writing those malicious files to a folder they have now have access to). Alternatively this functionality could be used to make a system unbootable by for example deleting the pci.sys driver. This has earned the vulnerability the name “Deletebug.”

How can I protect my organization/myself from this vulnerability?
As before with the Task Scheduler vulnerability; please continue to exercise standard vigilance in particular when using email; e.g. don’t click on suspicious links received within emails, social media, via chat applications etc. Don’t open attachments you weren’t expecting within an email (even if you know the person; since their email account or device they access their email from may have been compromised) and download updates for your software and devices from trusted sources e.g. the software/device vendors. This US-CERT advisory also provides advice for safely handling emails.

If you choose to; the firm 0patch has issued a micro-patch for this vulnerability. They developed the fix within 7 hours of the vulnerabilities disclosure. It blocks the exploit by adding impersonation to the DeleteFileW call. This was the same firm who micro-patched the recent Windows Task Scheduler vulnerability and JET vulnerabilities. Moreover; this vulnerability may be patched tomorrow when Microsoft releases their November 2018 updates.

As with the above mitigations; if you wish to deploy this micropatch please test how well it works in your environment thoroughly BEFORE deployment.

It can be obtained by installing and registering 0patch Agent from https://0patch.com Such micropatches usually install and need no further action when Microsoft officially patches the vulnerability since the micropatch is only active when a vulnerable version of the affected file is used; once patched the micropatch has no further effect (it is then unnecessary).

Thank you.

Protecting Against the Microsoft JET Database Zero Day Vulnerability

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Update: 24th October 2018:
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According to Acros Security CEO Mitja Kolsek the fix for this vulnerability from Microsoft is incomplete and mitigates but does not resolve the vulnerability.

As before; my assessment of the difficulty an attacker would face in exploiting this vulnerability remains accurate. The attack first needs you to take an action you wouldn’t otherwise take; if you don’t they can’t compromise your system.

Details of the incomplete nature of the vulnerability are not being disclosed while the patch is re-evaluated. Acros Security has notified Microsoft of this incomplete fix and is awaiting a response. In the meantime; their micropatch completely mitigates the vulnerability.

I’ll keep this post updated as more details become available. Thank you.

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Update: 9th October 2018:
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Microsoft’s scheduled updates for October 2018 resolve this vulnerability. Thank you.

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Original Post:
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In the latter half of last week; Trend Micro’s Zero Day Initiative publically disclosed (defined) a zero day vulnerability (defined) within the Microsoft JET Database Engine (defined).

Why should this vulnerability be considered important?
This vulnerability should be considered high but not critical severity. When exploited it can allow an attacker to execute code (to carry out any action of their choice) but they cannot initiate this automatically/remotely. They must socially engineer a potential victim into opening an attachment ( most likely sent over email or via instant messaging etc.). This attachment would need to be a specific file containing data stored in the JET database format. Another means would be visiting a webpage but 0patch co-founder Mitja Kolsec could not successfully test this means of exploit.

This vulnerability exists on Windows 7 but is believed to also exist on all versions of Windows including the Server versions.

How can I protect my organization/myself from this vulnerability?
At this time; a patch/update from Microsoft is pending and is expected to be made available in October’s Update Tuesday (9th October).

In the meantime; please continue to exercise standard vigilance in particular when using email; e.g. don’t click on suspicious links received within emails, social media, via chat applications etc. Don’t open attachments you weren’t expecting within an email (even if you know the person; since their email account or device they access their email may have been compromised) and download updates for your software and devices from trusted sources e.g. the software/device vendors. This US-CERT advisory also provides advice for safely handling emails.

If you choose to; the firm 0patch has also issued micro-patch for this vulnerability as a group of two patches. This was the same firm who micro-patched the recent Windows Task Scheduler vulnerability. As with the above mitigations; if you wish to deploy this micropatch please test how well it works in your environment thoroughly BEFORE deployment.

Thank you.

September 2018 Update Summary

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Update: 11th September 2018:
=======================
Earlier today Microsoft and Adobe made available their scheduled updates. Microsoft resolved 61 vulnerabilities more formally known as CVEs (defined).

At the time of writing; there are known issues but with only the now commonly occurring Windows 7 NIC being an issue this month:

KB4457128

KB4457144

KB4458321

Further details are available in Microsoft’s update summary for September.

Adobe issued 2 updates today:

Adobe ColdFusion (priority 2, resolves 6x critical CVEs)
Adobe Flash (priority 2, resoles 1x CVE)

As per standard practice if you use any of the above Adobe software, please update it as soon as possible especially in the case of Flash. Updates for Google Chrome will be available shortly either via a browser update or their component updater.

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:

====================
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.

====================
For this month’s Microsoft updates, I will prioritize the order of installation below:
====================
Microsoft Edge and Internet Explorer (multiple versions of Edge and IE affected)

Microsoft Hyper-V (affects Windows 10 and Windows 8.1 (including Windows RT 8.1) and their Server equivalents)

Windows Task Scheduler (relating to a previous blog post)

Security advisory for “FragmentSmack” CVE-2018-5391

====================
Please install the remaining updates at your earliest convenience.

As usual; 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.

Please find below summaries of other notable updates released this month.

Thank you.

=======================
Original Post:
=======================
In advance of further updates being released by Microsoft and Adobe this month I wish to provide details of notable updates made available so far. I will update this post as more updates are distributed.

Thank you.

=======================
Mozilla Firefox:
=======================
In early September Mozilla made available updated versions of Firefox:

Firefox 62: Resolves 1x critical CVE (defined), 3x high CVEs, 2x moderate CVEs, 3x low CVEs

Firefox ESR 60.2 (Extended Support Release): Resolves 1x critical CVE, 2x high CVEs, 2x moderate CVEs and 1x low CVE.

Further discussion of the other features introduced by Firefox 62 is available here. In the future Firefox will block multiple trackers which will boost privacy for it’s users. Future versions will implement these changes.

In-depth details of the security issues resolved by these updates are available in the links above. Details of how to install updates for Firefox are here. If Firefox is your web browser of choice, if you have not already done so, please update it as soon as possible to resolve these security issues.

=======================
Google Chrome:
=======================
Last week Google released version 69 (specifically version 69.0.3497.81) of Chrome celebrating Chrome’s 10th anniversary. This version not only incorporates fixes for 40 vulnerabilities but also includes many more improvements. Among them are an improved password manager/form filler and a change in how secured (encrypted) webpages are indicated.

Google Chrome updates automatically and will apply the update the next time Chrome is closed and then re-opened. Chrome can also be updated immediately by clicking the Options button (it looks like 3 stacked small horizontal lines, sometimes called a “hamburger” button) in the upper right corner of the window and choosing “About Google Chrome” from the menu. Follow the prompt to Re-launch Chrome for the updates to take effect.

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VMware
=======================
VMWare has issued a single security advisory so far in September:

Security advisory 1 (addresses 2 vulnerabilities of Low severity):

  • AirWatch Agent for iOS (A/W Agent)
  • VMware Content Locker for iOS (A/W Locker)

If you use the above VMware product, please review the security advisory and apply the necessary updates.

Protecting Against the Windows 10 Task Scheduler Zero Day Vulnerability

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Update: 5th September 2018:
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As previously advised; exercising caution when receiving emails with attachments will keep you safe from the following malware now exploiting this vulnerability.

Your anti-malware software will likely also protect you from this exploit since the majority of vendors are detecting (verified using VirusTotal) the file hashes listed in the security firm Eset’s blog post:

Eset have detected attackers delivering an exploit for this vulnerability via email. The exploit targets victims in the following countries:

  • Chile
  • Germany
  • India
  • Philippines
  • Poland
  • Russia
  • Ukraine
  • United Kingdom
  • United States

The attackers have made small changes of their own to the published proof of concept code. They have chosen to replace the Google Updater (GoogleUpdate.exe)(which runs with admin privileges (high level of integrity)) usually located at:

C:\Program Files (x86)\Google\Update\GoogleUpdate.exe

They replace the updater with a backdoor application of their own that is run with the highest privilege namely System level integrity. This is a stage one of their attack. If the attackers find anything of interest on the infected system a second stage is downloaded allowing them to carry out any commands they choose, upload and download files, shutting down an application or parts of Windows of their choice and listing the contents of the data stored on the system.

The attackers also use the following tools to move from system to system across (laterally) a network: PowerDump, PowerSploit, SMBExec, Quarks PwDump, and FireMaster.

Thank you.

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Original Post:
====================
With the disclosure early last week of zero day vulnerability (defined) I wanted to provide some advice on staying safe while a patch from Microsoft is being developed.

What systems are affected and how can an attacker use this vulnerability to compromise systems?
Once this pre-developed working exploit is delivered to a 64 bit Windows 10 system it can be used to provide an attacker with the highest level of privilege (System level access) on that system allowing them to carry out any action they choose. They can achieve this by changing permissions on any file stored on a system thus giving them the ability to replace/change any file. When a system service executes what it believes to be a legitimate file but is instead the attacker substituted file; the attacker obtains the privileged access of that service.

The effectiveness of this exploit has been verified by Will Dorman from the CERT/CC. 32 bit versions of Windows are also affected. For Windows 8.1 and Windows 7 systems; the exploit would require minor changes before it can result in the same level of effectiveness (but may be inconsistent on Windows 7 due to the hardcoded XPS printer driver (defined) name within the exploit).

An attacker must already have local access to the systems they wish to compromise but could obtain this using an email containing an attachment or another means of having a user click on a link to open a file. The base CVSS score of this vulnerability is 6.8 making it make of medium severity for the above reasons.

How can I protect myself from this vulnerability?
Standard best practice/caution regarding the opening of email attachments or clicking links within suspicious or unexpected email messages or links from unknown sources will keep you safe from the initial compromise this exploit code requires to work correctly.

The advisory from the CERT/CC has also been updated to add additional mitigations. BEFORE deploying these mitigations please test them thoroughly since they can “reportedly break things created by the legacy task scheduler interface. This can include things like SCCM and the associated SCEP updates”.

A further option you may wish to consider is the deployment of the following micropatch from 0Patch. This patch will automatically cease functioning when the relevant update from Microsoft is made available. As with the above mitigations; if you wish to deploy this micropatch please test how well it works in your environment thoroughly BEFORE deployment.

Further advice on detecting and mitigating this exploit is available from Kevin Beaumont’s post.

Thank you.