Tag Archives: Zero Day

February 2019 Update Summary

Earlier today Microsoft made available 13 bulletins and 3 advisories resolving 74 vulnerabilities (more formally known as CVEs (defined)) respectively. As always more details are available from Microsoft’s monthly summary page.

Also today Adobe released scheduled updates for the products listed below addressing 75 CVEs in total:

Adobe Acrobat and Reader: 71x priority 2 CVEs resolved (43 of the 75 are Critical, the remainder are Important severity)

Adobe ColdFusion: 2x priority 2 CVEs resolved

Adobe Creative Cloud Desktop Application: 1x priority 3 CVE resolved

Adobe Flash Player: 1x priority 2 CVE resolved

If you use the affected Adobe products; due to the public disclosure (defined) of CVE-2019-7089 as a zero day (defined) vulnerability, please install the Adobe Acrobat and Reader updates first followed by Flash Player and the remaining updates. I provide more detail on the zero day vulnerability in a separate post.

As we are accustomed to Microsoft’s updates come with a long list of Known Issues that will be resolved in future updates or for which workarounds are provided. They are listed below for your reference:

4345836
4471391
4471392
4483452
4486996
4487017
4487020
4487026
4487044
4487052

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 GDI+

Scripting Engine (CVE-2019-0590 , CVE-2019-0591 , CVE-2019-0593 , CVE-2019-0640  ,
CVE-2019-0642
, CVE-2019-0648 , CVE-2019-0649  , CVE-2019-0651 , CVE-2019-0652 , CVE-2019-0655 , CVE-2019-0658)

Windows DHCP

Microsoft Exchange

Microsoft SharePoint and CVE-2019-0604

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

Thank you.

Adobe Reader Vulnerability Disclosed

Yesterday; the security firm 0patch released a micropatch for a vulnerability that was publicly disclosed (defined) in late January.

Why should this vulnerability be considered important?
The vulnerability allows for the extraction/disclosure of the NTLMv2 hashes (defined) associated with your Windows login account to be sent to an attacker when you open a specifically modified PDF document, The information is sent via the SMB protocol (defined) to the attacker essentially allowing the document “to phone home” to them.

Adobe Reader DC (2019.010.20069 and earlier) are affected. This vulnerability is similar to a now patched vulnerability from last year namely; CVE-2018-4993, The new vulnerability is caused by the fact that while a user is warned via a dialog box when opening an XML style sheet via the HTTP protocol; when using the SMB protocol and while following a UNC (defined) link; no such warning appears.

How can you protect your organisation and yourself from this vulnerability?
Please apply the update made available by Adobe earlier today. If for any  reason you cannot update right now, please consider the micropatch from 0patch. A YouTube video of the micropatch in action is available from the following link:

The micropatch does not require a reboot. The patch does not need to be uninstalled once you later install the update from Adobe.

Thank you.

Apple KeyChain Vulnerability Disclosed

Last week a security researcher publicly disclosed a vulnerability within Apple macOS’ Keychain (Apple’s password management system). The exact proof of concept code has not been released.

TL DR:  This vulnerability is currently unpatched by Apple. Be cautious of the links you click on, email attachments and applications you download/open. Keep your system current with already released updates. Watch for updates from Apple in the near future.

Why should this vulnerability be considered important?
This vulnerability affects all versions of Apple macOS up to the most recent 10.14.3 (Mojave). Apple Keychain is used to store passwords for application, websites and servers. This information is encrypted by default blocking access via other means without your permission.

However; the exploit allows an attacker to access this information from a standard user account (thus not requiring root (defined)(privileged) access) without generating a password prompt. The keychain must first be unlocked but it is when you are logged into the system. The System keychain which contains (among other items) is not affected. Thus, if the attacker can persuade you to run an application of their choice (e.g. substituting an app that looks like an app you regularly download manually); they could obtain your passwords/sensitive information. A YouTube video demonstrating the custom application designed to exploit this is provided below:

https://youtu.be/nYTBZ9iPqsU

How can I protect myself?
Please see the TL DR above. You should also consider manually locking your keychain or setting a keychain specific password (further details below).

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Lock your Keychain:
Open Keychain Access in the Applications: Utilities folder. Select your keychain (usually your user name) in the drawer (click on Show Keychains in the toolbar if it’s not visible). Then choose Edit: Change Settings For Keychain keychain name. Select Lock After 5 Minutes Of Inactivity (or lower according to your preference).

Password Protect Your Keychain:
Open the Keychain Access application, and select your keychain in the drawer. Select Edit: Change Password For Keychain keychain name, and then enter a new password.

With thanks to MacWorld:

===========

Why did the researcher not disclose this to Apple privately?
The researcher, Linus Henze chose not to privately disclose this to Apple since while Apple have a bug bounty for iOS which is by invite only; they don’t have such a program for macOS. The researcher wishes to highlight this omission. A quote from the researcher is included below (my thanks to Sergiu Gatlan of BleepingComputer.com) for this:

“Please note that even if it looks like I’m doing this just for the money, this is not my motivation at all in this case. My motivation is to get Apple to create a bug bounty program. I think that this is the best for both Apple and Researchers. I really love Apple products and I want to make them more secure. And the best way to make them more secure would be, in my opinion, if Apple creates a bug bounty program (like other big companies already have)”

Separately he is not the only researcher to be criticising Apple’s approach to vulnerability remediation. Ian Beer of Google Project Zero publicly criticised Apple last August for simply fixing vulnerabilities rather than thinking of them in an exploit context namely “Why is this bug here? How is it being used? How did we miss it earlier? What process problems need to be addressed so we could have found [the bug] earlier? Who had access to this code and reviewed it and why, for whatever reason, didn’t they report it?”

Thank you.

December 2018: Further Zero Day Vulnerabilities Disclosed

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Update: 6th February 2019
=======================
In mid-January; the security firm 0patch issued a micropatch for what I refer to as vulnerability 4 (discussed below). As before the patch can be applied and will protect your devices until Microsoft can issue a finalised update via the regular channels.

The patch is only available for Windows 10 Version 1803. 0patch have requested that you contact them if you wish to obtain a patch for another version of Windows 10. They have published a YouTube video of the patch preventing the proof of concept code from working as the attacker intended.

Approximately a week after this micropatch was issued; another micropatch was made available; this time for what I refer to as vulnerability 3 (discussed below). That patch is available for Windows 10 Version 1803 64 bit and Windows 7 bit. As before 0patch have requested that you contact them if you wish to obtain a patch for another version of Windows. Another YouTube video is available demonstrating the micropatch preventing the proof of concept code from reading any file on the system as the attacker intended. It does this by changing the permissions on the temporary MSI file created by Windows Installer. The micropatch was more complex than originally thought to create. 0patch wanted to issue their patch before the Holiday period in December but were unable to do so since it required more thorough testing before being made available but there was not enough time left for that testing.

The micropatch does not require a reboot. As before the patch does not need to be uninstalled once you later install the update from Microsoft.

At this time, it is assumed that Microsoft will issue a patch for these vulnerabilities in February but they may be more complex (similar to the previous JET vulnerability) and require further time to refine the fixes.

Thank you.

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Original Post:
=======================
In the 3rd week of December; a security researcher using the name SandboxEscaper (who we have discussed twice before on this blog) announced a 3rd zero-day (defined) vulnerability followed by a 4th on the 30th of December.

For the 3rd vulnerability: Windows 7 and Windows 10 are confirmed as impacted. Windows 8.1 may also be vulnerable. For the 4th vulnerability; Windows 10 Version 1803 (Build 17134) has been confirmed as impacted (it’s unknown if newer builds of Window 10 or if Windows 7/8.1 are vulnerable).

How severe are these vulnerabilities and what is their impact?
I’ll break these into 2 sections:

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Vulnerability 3:
Arbitrary file read issue: Uses MsiAdvertiseProduct:
=======================
From the limited information available this vulnerability does not appear to be remotely exploitable. The attacker would already need to have compromised an account on your Windows system in order to run the necessary proof of concept code. This vulnerability should be considered medium but not critical severity. When exploited it can allow an attacker to read/copy any files they choose using the permissions from the Windows Installer Service namely LocalSystem privileges (the highest level of privilege)(defined). The vulnerability makes use of a time to check to time to use (TOCTOU) race condition type.

In the same manner as the previous vulnerabilities it 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 (within emails, links within IM clients or social networks). Security researcher Will Dormann found this exploit inconsistent when used. Meanwhile Acros Security CEO Mitja Kolsek stated It was very likely a micropatch for this exploit would be available before the holiday period.

=======================
Vulnerability 4:
Arbitrary file overwrite issue: Proof of concept overwrites pci.sys
=======================
As above; this vulnerability does not appear to be remotely exploitable. The attacker would already need to have compromised an account on your Windows system in order to run the necessary proof of concept code. This vulnerability should be considered medium but not critical severity. When exploited it can allow an attacker to overwrite pci.sys with information about software and hardware problems, collected through the Windows Error Reporting (WER) but the attacker can also influence what data is used to overwrite the original file. The vulnerability again makes use of a race condition which means that the exploit doesn’t always provide the attacker with the intended result. This is especially true for systems with a single CPU core.

However; the choice of pci.sys for the proof of concept was an example; any file could be used (confirmed by Will Dormann).

How can I protect my organization/myself from these vulnerabilities?
The same advice issued for the first two zero day disclosures again applies here. This US-CERT advisory also provides advice for safely handling emails.

If you wish to deploy the micropatch from the firm 0patch; please test how well it works in your environment thoroughly BEFORE deployment in your production environment.

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.

December 2018 Update Summary

====================
Update: 3rd January 2019
====================
Apologies for the delay.

Microsoft made available an out of band (un-scheduled) security update available for Internet Explorer on the 19th of December. This vulnerability is being actively exploited; thus if you have not already done, please update your Windows systems. All supported Windows Server and consumer versions of Windows are affected. The full table of affected Windows versions is available here from Microsoft.

For Lenovo laptops running Windows 10 Version 1607 with less than 8 GB of system memory (RAM); Microsoft has provided the following workarounds since this new security update inadvertently causes these systems to be unbootable:

====================
Restart the affected machine using the Unified Extensible Firmware Interface (UEFI). Disable Secure Boot and then restart.

If BitLocker is enabled on your machine, you may have to go through BitLocker recovery after Secure Boot has been disabled.

Microsoft is working with Lenovo and will provide an update in an upcoming release.
====================

Thank you.

====================
Original Post:
====================
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:
====================
Microsoft Edge and Internet Explorer (multiple versions of Edge and IE affected)

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

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

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

Update:
Separately; Firefox 64 now includes small pop-ups known as “snippets” which turned out to be an experiment by Mozilla. If you wish to turn them off; the steps are available here.

Meanwhile extension recommendations within Firefox 64 can be disabled using these steps.

=======================
Google Chrome:
=======================
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.

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