Tag Archives: Zero Day

Botnet Targeted Unpatched Counter-Strike Vulnerabilities

In mid-March the security firm Dr. Web published details of a botnet (defined) they were able to shut down affecting players of the classic first-person shooter (FPS) game; Counter-Strike 1.6.

Why should this development be considered significant?
The report made available by Dr. Web showed that at it’s height the botnet resulting from the distribution of the Trojan (defined) Belonard numbered up to 39% of all the available game servers (1951 out of 5000) listed for Counter-strike gamers to choose from.

How were gamers systems infected?
One of the popular services offering servers to play on exploited 2 zero day (defined) remote code execution vulnerabilities within the 1.6 version of the Counter-Strike client to install Trojan Belonard within a gamer’s system. Researchers from Dr. Web found that this game remains very popular and can be played by 20,000 individuals on average at a time.

Counter-Strike can make use of dedicated servers that gamers can choose to connect to. These servers offer reduced lag, greater reliability while some monetised servers offer access to special weapons and protection against bans.

In an example scenario, a gamer might launch the official Steam gaming client. The client automatically will display a list of servers the player can connect to. Those with the lowest (lower is better) ping rate will be displayed at the top of the list. This list will also contain publicly available Valve (the company which created and maintains the Steam client) servers. However, the Trojan Belonard once it has infected a system it re-orders the servers offered to another system (placing them high in the list you see) in order to spread further. You may think you are connecting to a server with a low ping when in fact connecting to a malicious server which then infects your system with the Trojan. It does this by exploiting a remote code execution (defined: the ability for an attacker to remotely carry out any action of their choice on your device) vulnerability within the Counter-Strike client. A more detailed description and diagram is available from Dr. Web’s analysis of this threat. Your system will now contribute to spreading the Trojan by re-ordering the server list we discussed above.

The botnet herder did this in order to make more money since their other more legitimate servers would also be displayed high in the list of servers and those charge a fee for their use.

What happened to this botnet?
Dr. Web was successful in disrupting this botnet by coordinating with the registrar of the reg.ru domain name to shut down the websites used by the Trojan thus protecting new gamers from becoming infected. Furthermore, the domain generation algorithm (DGA)(defined); is being monitored by Dr. Web in order to continue to sinkhole (defined) the domains the malware attempts to use to continue spreading itself.

How can I protect myself from this threat or clean it from my system if I am already infected?
Unfortunately; the only way to prevent this botnet from being re-activated by whoever created it is for the zero-day vulnerabilities within the Counter-Strike client to be patched. Given the age and lack of financial reward to Valve to do this; that is unlikely.

If you suspect or know your system is infected with this malware; update your anti-malware software and run a full system scan. If this does not remove the malware you can use the free version of Malwarebytes to perform a scan and remove the malware. If you suspect any remnants remain you can use the additional anti-malware scanners linked to on this blog to remove them. In this case; RogueKiller, AdwCleaner and PowerEraser would be the most suitable for this malware.

Thank you.

March 2019 Update Summary

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Updated: 21st March 2019
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Two of the vulnerabilities patched by Microsoft (CVE-2019-0797CVE-2019-0808) were zero day (defined) vulnerabilities being actively exploited in the wild. Four other vulnerabilities were publicly known (CVE-2019-0683CVE-2019-0754CVE-2019-0757 and CVE-2019-0809).

Separately the Google Chrome vulnerability mentioned below namely CVE-2019-5786 was also being exploited by attackers.

After publishing my original post; Adobe and Microsoft jointly reported that while a newer version (32.0.0.156) of Flash Player was made available it only resolves non-security bugs.

I have updated the suggested installation order (below) to reflect this new information. Thank you.

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Original Post:
====================
As scheduled; earlier today Microsoft and Adobe made available their security updates. Microsoft addressed 65 vulnerabilities (more formally known as CVEs (defined)) with Adobe resolving 2 vulnerabilities.

For Adobe; if you have not already done so; if you manage an installation of Adobe ColdFusion or know someone who does, please apply the necessary updates made available earlier this month. That update addressed a single priority 1 zero day (defined) vulnerability being exploited in the wild. Today’s Adobe updates are as follows:

Adobe Digital Editions: 1x priority 3 CVE resolved

Adobe Photoshop CC: 1x priority3 CVE resolved

If you use the affected Adobe products; please install their remaining priority 3 updates when you can.

This month’s list of Known Issues is now sorted by Microsoft within their monthly summary page and applies to all currently supported operating systems:

KB4489878          Windows 7 Service Pack 1, Windows Server 2008 R2 Service Pack 1 (Monthly Rollup)

KB4489881          Windows 8.1, Windows Server 2012 R2 (Monthly Rollup)

KB4489882          Windows 10 version 1607, Windows Server 2016

KB4489883          Windows 8.1, Windows Server 2012 R2 (Security-only update)

KB4489884          Windows Server 2012 (Security-only update)

KB4489885          Windows 7 Service Pack 1, Windows Server 2008 R2 Service Pack 1 (Security-only update)

KB4489891          Windows Server 2012 (Monthly Rollup)

KB4489899          Windows 10 version 1809, Windows Server 2019

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: CVE-2019-0797CVE-2019-0808

Windows DHCP Client: CVE-2019-0697 , CVE-2019-0698 , CVE-2019-0726

Microsoft XML: CVE-2019-0756

Scripting Engine: CVE-2019-0592 , CVE-2019-0746 , CVE-2019-0639 , CVE-2019-0783 , CVE-2019-0609 , CVE-2019-0611 , CVE-2019-0666 , CVE-2019-0769 , CVE-2019-0665 , CVE-2019-0667 , CVE-2019-0680 , CVE-2019-0773 , CVE-2019-0770 , CVE-2019-0771 , CVE-2019-0772

Visual Studio Remote Code Execution Vulnerability: CVE-2019-0809

Microsoft Active Directory: CVE-2019-0683

NuGet Package Manager Tampering Vulnerability: CVE-2019-0757

Windows Denial of Service Vulnerability: CVE-2019-0754

Microsoft Dynamics 365: a privilege escalation vulnerability (defined) has been addressed (this product is also widely deployed)

If you use Microsoft IIS (Internet Information Services), please review advisory: ADV190005

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

As always; 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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Google Chrome:
=======================
Google released Google Chrome version 72.0.3626.121 to address a single zero day (defined) vulnerability under active exploit. The vulnerability was a high severity use-after-free (defined) flaw in Chrome’s FileReader API (defined) which could have led to information disclosure of files stored on the same system as Chrome is installed.

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.

=======================
Notepad++:
=======================
Notepad++ 7.6.4 was released on the 6th of March resolving 8 security issues. This version follows another from January which resolved 7 other vulnerabilities. If you use Notepad++, please update to the newest version to benefit from these security fixes.

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.

=======================
Mozilla Firefox
=======================
Update: 25th March 2019: As detailed in the Pwn2Own 2019 results post; Mozilla released a further update for Firefox and Firefox ESR bringing their version numbers to 66.0.1 and 60.6.1 respectively. Both updates resolve 2x critical CVEs. Please consider updating to these versions as soon as possible.

=======================
In the latter half of March Mozilla issued updates for Firefox 66 and Firefox ESR (Extended Support Release) 60.6:

Firefox 66.0: Resolves 5x critical CVEs (defined), 7x high CVEs, 5x moderate CVEs and 4x low CVEs

Firefox 60.6: Resolves 4x critical critical CVEs, 4x high CVEs and 2x moderate CVEs

Firefox 66 introduces better reliability (since crashes have been reduced) and improved performance. In addition, smooth scrolling has been added. The blocking of websites automatically playing audio or video content is now also present. These and other features are discussed in more depth here and here.

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 benefit from the above changes.

=======================
VMware:
=======================
VMware issued 2 security advisories during March:
Security Advisory 1: Addresses 2x important severity CVEs in the following products:

VMware Player
VMware Workstation Pro

Security Advisory 2: Addresses 1x moderate severity CVE in the following products:

VMware Horizon

If you use the above VMware products, please review the security advisories and apply the necessary updates.

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Putty:
=======================
Putty, the open source and highly popular SSH (defined) client for Windows, was updated to version 0.71 in mid-March. It contains 8 security fixes (see below). They are a result of the bug bounties awarded through the EU-Free and Open Source Software Auditing (EU-FOSSA) (discussed previously in this post). Version 0.71 is downloadable from here.

If you use Putty, please update it to version 0.71. Thank you.

Security vulnerabilities fixed:

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Nvidia Geforce Experience Software:
=======================
In late March , Nvidia released a security advisory for their Geforce Experience software for Windows. This update resolves 1 high severity vulnerabilities (as per their CVSS base scores). The necessary updates can be applied by opening Geforce Experience which will automatically updated it or the update can be obtained from here.

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GOG Galaxy
=======================
Golden Old Games (GOG) has published an update for their popular game distribution platform GOG Galaxy. It resolves 2 critical vulnerabilities. Additionally, 2 high severity and 2x medium severity vulnerabilities were also resolved. These vulnerabilities are discussed in more detail in this Cisco Talos blog post and within this Kaspersky ThreatPost article. Please update GOG Galaxy to version 1.2.54.23 or later to resolve these vulnerabilities.

I don’t often post about vulnerabilities in gaming clients/gaming distribution clients but like any software; security updates can and are made available for them.

Adobe Flash Player 2019 Update Tracker

In a similar manner to previous years this post will track the number of vulnerabilities patched within Adobe Flash for 2019. This will be the penultimate year of tracking these numbers since Flash Player is due to be decommissioned in 2020.

As always this post will be updated throughout the year with the details of vulnerabilities being patched and if they are being exploited in the wild. Apologies for not making this 2019 tracker available sooner.

Thank you.

=======================

=======================
8th  January 2019: Adobe releases Flash Player v32.0.0.114 This update is a non-security update addressing only feature and performance bugs.

12th February: Adobe releases Flash Player v32.0.0.142 resolving 1x priority 2 CVE.

12th March: Adobe have not released any Flash Player updates this month.

12th March 2019: Adobe makes available Flash Player v32.0.0.156 to resolve non-security bugs only.

9th April 2019: Adobe releases Flash Player v32.0.0.171  resolving 2x priority 2 vulnerabilities (CVEs) (1x Critical and 1x Important severity).

14th May 2019: Adobe releases  Flash Player v32.0.0.192 to resolve a single critical CVE.

11th June 2019: Adobe releases Flash Player v32.0.0.207 just like last month to resolve a single critical CVE.

=======================
Update: 19th February 2019: The timeline was created to include the Adobe Flash Player updates for January and February 2019. At the time of writing no exploits for the issue fixed by the February update are known to be taking place.

Update 12th March 2019: The timeline was updated to reflect that Adobe did not issue Flash Player updates this month.

Update: 21st March 2019: The timeline was updated to reflect that Adobe did publish a Flash Player update for March 2019 but it is a non-security update.

Update: 10th April 2019: The timeline was created to include the Adobe Flash Player updates for April 2019. At the time of writing no exploits for the issues resolved fixed by the April update are known to be taking place.

Update: 12th June 2019: The timeline was created to include the Adobe Flash Player updates for May and June 2019. At this time no exploits for the issues resolved in either month are known to be currently taking place.
=======================

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.

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Nvidia Graphics Drivers:
=======================
8 security vulnerabilities with the most severe having a CVSS V3 (defined) base score of 8.8 have been resolved within Nvidia’s graphics card drivers (defined) in February. These vulnerabilities affect Linux FreeBSD, Solaris and Windows. The steps to install the drivers are detailed here (and here) for Ubuntu and here for Linux Mint. Windows install steps are located here. If you use affected Nvidia graphics card, please consider updating your drivers to the most recent available.

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7-Zip:
=======================
In the 3rd week of February; 7-Zip version 19.00 was released. While it is not designated as a security update; the changes it contains appear to be security related. While 7-Zip is extremely popular as a standalone application; other software such as Malwarebytes Anti-Malware, VMware Workstation and Directory Opus (among many others) all make use of 7-Zip. Directory Opus version 12.2.2 Beta includes version 19.00 of the 7-Zip DLL.

If you use these software applications or 7-Zip by itself, please update these installed applications to benefit from these improvements.

=======================
Changes:
=======================
– Encryption strength for 7z archives was increased:
the size of random initialization vector was increased from 64-bit to 128-bit, and the pseudo-random number generator was improved.
– Some bugs were fixed.
=======================

If you are using the standalone version and it’s older than version 19, please consider updating it.

=======================
Mozilla Firefox
=======================
In mid-February Mozilla issued updates for Firefox 65 and Firefox ESR (Extended Support Release) 60.5:

Firefox 65.0.1: Resolves 3x high CVEs (defined)

Firefox 60.5.1: Resolves 3x high CVEs

As always; 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 benefit from changes such as improvements to Netflix playback, color management on Apple macOS and resolving audio/video delays during WebRTC calls etc.

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Wireshark 3.0.0, 2.6.7 and 2.4.13
=======================
v3.0.0: 0 security advisories (new features and benefits discussed here and here)

v2.6.7: 3 security advisories

v2.4.13: 3 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 (v3.0.0, v2.6.6 or v2.4.12). 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.

Note: from this post onwards, I will only report on the most recent (v3.0) and previous branches (v2.6) of Wireshark.

Thank you.

Adobe Reader Vulnerability Disclosed

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Updated: 26th February 2019
====================
After the update was issued by Adobe; the original researcher who disclosed it found a bypass and again reported it to Adobe. The bypass was assigned another CVE number; CVE-2019-7815

It has now been addressed by a further update made available by Adobe last Thursday. If you use Adobe Acrobat or Reader, please ensure it is up to date:

Thank you.

====================
Original Post
====================
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:

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