Tag Archives: DLL Hijacking

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.

May 2018 Update Summary

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Update: 5th June 2018:
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As discussed in the post below, the zero day vulnerability (defined) designated as CVE-2018-8174 (defined) patched by Microsoft last month has since been incorporated into the RIG exploit kit (defined). The attackers have used the extra detail provided from anti-malware vendors, GitHub (the popular source code repository) and MetaSploit (defined) to create this exploit.

As detailed below, the vulnerability is considered medium severity; however it also requires actions from the user before it take any malicious action usually opening a malicious file or visiting a malicious website.

Please use caution for any email that you receive with an attachment you weren’t expecting. Thank you.

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Update: 31st May 2018:
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A vulnerability in the JScript (Microsoft’s implementation of JavaScript (defined) has been responsibility disclosed (defined) by Dmitri Kaslov of Telspace Systems, who passed it along to Trend Micro’s Zero-Day Initiative (ZDI). At this time, this vulnerability is un-patched and is thus a zero day vulnerability (defined).

The vulnerability allows a remote attacker to execute malicious instructions of their choice on the victim’s system but only in the context of a sandboxed (defined) environment. In other words, the code cannot itself be used to fully compromise a system. It must be leveraged with another vulnerability to have the potential of fully compromising a system making the vulnerability less serious.

At this time, components within Windows such as wscript.exe and Internet Explorer should not not permitted to run untrusted JScript code. This mitigation (please see the heading near the end of the page named: “How To Tell Explorer To Open .JS Files With Notepad”) may be of assistance with implementing this recommendation.

I will update this post when this vulnerability is patched by Microsoft or when further information becomes available.

Thank you.

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Update: 18th May 2018:
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Other updates made available by Microsoft for the Spectre Variant 2 vulnerability are:

kb4100347

This update was not offered to my Windows laptop running Version 1803. As you know it contains an Intel Core i7 6500U CPU. I downloaded the version 1803 update from the Microsoft Catalog and it installed successfully. My system is showing the full green result when the PowerShell command Get-SpeculationConntrolSetting is run. It results in the final screenshot shown with this article. Further tips on running this useful command are provided in this Microsoft support article, please see the headings “PowerShell Verification using the PowerShell Gallery (Windows Server 2016 or WMF 5.0/5.1)” or “PowerShell Verification using a download from Technet (earlier operating system versions and earlier WMF versions)” depending on your version of Windows.

Microsoft have also issued an update for Windows version 1709 to resolve a vulnerability again introduced by their previous patch. This resolution was provided in update kb4103727. Further details are available in Alex Ionescu’s tweet (a security architect with CrowdStrike and Windows Internals expert). Previous Spectre V2 patches were kb4091666 and kb4078407

This issue was already addressed in version 1803 of Windows.

If any of the above updates apply for your version of Windows, please install them. If the updates are already present or are not required; the installation will not proceed when you manually attempt it.

Thank you.

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Update: 17th May 2018:
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Adobe have since issued further updates to resolve critical vulnerabilities within Adobe Acrobat DC, Adobe Reader DC and Photoshop. Further details of the zero day (defined) vulnerabilities addressed in Adobe Acrobat/Reader are available here and here.

Adobe Acrobat and Reader (priority 1, 47 CVEs)

Adobe Photoshop CC 2018 and 2017 (priority 3, 1 CVE).

Further updates are listed at the end of this post. Thank you.

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Update: 10th May 2018:
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Further details have emerged of another zero day (defined) vulnerability affecting Windows Server 2008 R2 and Windows 7.

CVE-2018-8120 is an elevation of privilege (defined) vulnerability but can only be exploited if the attacker has already compromised the user account of the system allowing the attacker to log in when they choose. Upon logging in the attacker could obtain kernel level access/permissions (defined) by elevating their privileges to carry out any action they choose.

The prioritised list below has been updated to reflect this. Thank you.
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Original Post:
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Apologies for only posting an update summary last month. Other commitments meant I didn’t have the bandwidth to contribute more. I’ll try to make more time this month. Thanks.
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Earlier today Microsoft released their scheduled monthly security updates resolving 67 vulnerabilities. Notably Windows 10 Version 1803 receives it’s first update this month. Windows Server 2016 Version 1803 remains in testing in advance of it’s upcoming release. As always Microsoft have provided further details are provided within their Security Updates Guide.

There are 4 knowledge base articles detailing potential issues (all of which are pending resolutions) you may experience upon installing these updates. They are listed below for your reference:

4103712

4103718

4103723

4103727

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Separately, Adobe released updates for 3 of their products, namely:

Adobe Creative Cloud Desktop Application (priority 2 (overall), 3x CVEs)

Adobe Connect (priority 2, 1x CVE)

Adobe Flash Player (priority 2, 1x CVE)

Non-Microsoft browsers should update automatically e.g. Google Chrome should release a browser update in the coming days or will use their component update feature (the update was not available at the time of writing). Like last month; Microsoft issued a security advisory containing details of their updates

As always; 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 (since Secunia PSI was phased out on the 20th of April):
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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. A useful list of all CVEs for this month is present here:
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Windows VBScript Engine Remote Code Execution Vulnerability (a zero day (defined) vulnerability)

Win32k Elevation of Privilege Vulnerability

Microsoft Edge and Internet Explorer (similar to last month multiple versions of Edge and IE affected with many of the CVEs affecting the Microsoft Scripting Engine))

Microsoft Hyper-V (Update 1 and Update 2)

Microsoft Office (detailed list available here)
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Please install the remaining updates at your earliest convenience.

One of the vulnerabilities addressed by Microsoft this month, namely CVE-2081-8897: Windows Kernel Elevation of Privilege Vulnerability arose due to the misinterpretation of documentation from Intel regarding how a CPU (defined) raise a debug (defined) exception to transfer control to debugging software (usually used by a software developer). The specific instructions were the assembly language instructions (defined) MOV to SS and POP to SS.

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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Malwarebytes Anti-Malware
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Last week Malwarebytes updated their anti-malware product to version 3.5.1. The full list of improvements is available here but it also updated their include 7-Zip to version 18.05. I verified this manually since the above release notes did not make reference to it. Further details of the 7-Zip update are available in my April blog post.

Moreover; Directory Opus updated their product to version 12.8.1. Beta adding new DLLs (defined) for 7-Zip and UnRAR once again to address the vulnerabilities found within the UnRAR DLL also used by 7-Zip.

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Mozilla Firefox:
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This month Mozilla made available security updates for Firefox and Firefox ESR (Extended Support Release):

9th May: Firefox 60.0: Resolves 2x critical CVEs, 6x high, 14 moderate CVEs and  4x low severity CVEs

9th May: Firefox ESR 52.8: Resolves 2x critical, 5x high, 3x moderate CVEs

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 66.0.3359.170 to address 4 number of vulnerabilities and to include a newer version of Adobe Flash Player.

One of the four vulnerabilities addressed relates to how Chrome handles browser extensions resolving a privilege escalation issue (defined). Further details are availability here.

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Wireshark 2.4.7 and 2.6.1
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v2.4.7: 6 security advisories

v2.6.1: 9 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 (v2.6.1) or v2.4.7). 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.

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USB Denial of Service (DoS) Will not Receive a Fix
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In other vulnerability related news; a denial of service issue (defined) privately/responsibly disclosed (defined) by a security researcher Marius Tivadar will not fixed by Microsoft with a security update since the vulnerability requires physical access to the target system or social engineering (defined) and does not result an attacker being able to execute code of their choice on the affected system.

In my opinion; this is justified since if an attacker can obtain physical access to your system it significantly enhances the damage they can do. This statement also forms part of Microsoft’s 10 Immutable Laws of Security.

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Update: 31st May 2018
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VideoLAN VLC:
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Yesterday VideoLAN made available VLC version 3.0.3 for Linux, Windows, macOS, BSD, Android, iOS, UWP and Windows Phone. It’s release notes detail one potential security issue (buffer overread  (defined)) and other 3rd party libraries being updated to address security issues. No specific numbers were provided. A large number of non-security issues were also resolved.

Please update to version 3.0.3 to benefit from these improvements.

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Google Chrome:
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Earlier this month Google made available version  67 delivering 34 security issues. The improvements part of this new version are discussed in this Bleeping Computer article.

Moreover this version includes an early implementation of a new user interface for the tabs, address bar, settings button (sometimes referred to as the “chrome” (no pun intended) of an application). This article provides more details and includes steps to enable the new UI. I have done so and it’s a subtle difference but I already really like it. The Incognito mode is even more noticeable. The UI also seems more responsive (but that may be placebo effect).

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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Apple Security Updates:
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In late May Apple made available the following updates. Interestingly while the updates were available; no specific details of the improvements they include (security or otherwise) are yet available.

Initially, further details of the updates made available by Apple are emerging. Sophos have theroized that Apple have made improvements to the iOS Messages app making it more stable and less susceptible to crashing. They are thus recommending that you install the iOS 11.4 update as soon as possible.

They also discuss the addition of a new security feature which blocks access to a mobile device if the passcode has not been entered within the last seven days. This change is expected to become part of 11.4.1 and a stricter form for iOS 12. After this time the Apple Lightning cable will only charge the device and not allow data access. This appears to be part of Apple’s response to law enforcement and forensics firms accessing Apple devices attempting to collect evidence of the device’s owner’s wrongdoings.

Further details have since emerged for these Apple security updates:

Apple iOS v11.4 (resolves 35x CVEs (defined))

Apple tvOS 11.4 (resolves 24x CVEs)

Apple watchOS 4.3.1 (resolves 20x CVEs)

Apple iTunes version 12.7.5 for Windows (resolves 16x CVEs)

Moreover, BleepingComputer have discussed two of the vulnerabilities patched were buffer overflows (defined) both present in the kernels (defined) of iOS, macOS, tvOS and watchOS.

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Please see these links from Apple for advice on backing up your iPhone and iPad. Advice for updating tvOS is available here while the steps for updating the Apple Watch are available here.

As always; further details of these updates are available on Apple’s dedicated security updates page.

For advice on how to install updates for Apple devices, please see the steps detailed at the end of this Sophos blog post as well as this link (from my “Protecting Your PC” page).

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Hitman Pro:
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As recommended on my Tools and Resources page, Hitman Pro (now part of Sophos Security) has been updated to version 3.8.20 (Build 294). This update resolves a vulnerability relating to DLL hijacking (defined)(apologies; for this link you may need to dismiss several adverts before the requested page loads). Any previous version of the tool should update automatically when opened to the most recent version.

February 2018 Update Summary

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Update: 28th February 2018:
Please scroll down in this post to view more recent software updates available since the original posting date of the 13th of February 2018. Thank you.
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Earlier today Microsoft made available their expected monthly security updates to resolve 50 vulnerabilities more formally known as CVEs (defined). As always further details are provided within Microsoft’s Security Updates Guide.

At the time of writing there are no Known Issues for this months updates.

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In addition to these updates; Adobe released updates for the following products:

Adobe Experience Manager (resolves 2x priority 3 CVEs)

Adobe Acrobat and Reader (priority 2, 41 CVEs)

Flash Player v28.0.0.161 (priority 1, 2 CVEs) (released on the 6th of February):

As always; you can monitor the availability of security updates for most your software from the following websites (among others) or use Secunia PSI:
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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. A useful list of all CVEs for this month is present here:

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CVE-2018-0825: StructuredQuery Remote Code Execution Vulnerability

CVE-2018-0850 and CVE-2018-0852 : Microsoft Office Outlook (separately the Office Equation Editor was disabled by this months updates to attempt to prevent further exploitation).

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 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.

Similar to last month (due to the availability of further mitigations for x86 (32 bit) version of Windows); please take extra care with your back up to ensure you can restore your systems should you wish to revert your systems prior to installing the Meltdown and Spectre patches should you wish to uninstall the Security only bundle of updates or the updates are causing your system to become unstable or to lower its performance.

Thank you.

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Update: 26th February 2018
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VMware Updates:
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In addition to last month’s VMware updates; further security updates have been issued in February. The affected products/appliances are listed below.

Please review the above linked to security advisories and knowledge base article and apply the necessary updates and mitigation steps.

  • VMware vCloud Usage Meter (UM) 3.x
  • VMware vIdentity Manager (vIDM) 2.x and 3.x
  • VMware vCenter Server (vCSA) 5.5, 6.0 and 6.5
  • VMware vSphere Data Protection (VDP) 6.x
  • VMware vSphere Integrated Containers (VIC) 1.x
  • VMware vRealise Automation (vRA) 6.x and 7.x

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Google Chrome:
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This month Google made available 2 updates for Google Chrome; one in early February and the other in mid-February each resolving 1 security issue.

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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VideoLAN VLC:
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On the 28th of February VideoLAN made available VLC version 3.0.1 for Linux, Windows, macOS, BSD, Android, iOS, UWP and Windows Phone. It’s release notes detail fixes for 2 security issues (use-after-free (defined) and stack buffer overflow (defined)) and a further potential security issue (out of bounds (defined) read). More than 30 other non-security issues were also resolved.

Please update to version 3.0.1 to benefit from these improvements.

In early February VideoLAN made available version 3.0 for Linux, Windows, macOS, BSD, Android, iOS, UWP and Windows Phone. While its release notes do not detail any vulnerabilities addressed it includes smashing stack protection (SSP)(defined) and high entropy ASLR (HEASLR, also previously discussed on this blog)(ASLR: defined) for 64 bit versions of VLC. If you use VLC, you may wish to update to this version to benefit from the improved performance and features it offers while also increasing security.

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Skype:
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Earlier this month it was reported (for example here and here) that Skype contained an important elevation of privilege (defined) security vulnerability allowing the use of DLL (defined) hijacking (defined) within its update installer.

This vulnerability required a significant volume of remediation and was not addressed within the existing 7.40 version of Skype. Microsoft subsequently issued version 8 in October to address this vulnerability. 8.16.04 is the most recent version of Skype at the time of writing.

The above referenced version is the desktop version of Skype rather than the Microsoft Store app version which will be offered for Windows 10 installations.

Windows 7 and Windows 8.1 will be offered the 8.16.04 desktop version. Updates are available from skype.com Please note; for existing 7.40 users; an automatic update prompt will not display alerting you to the presence of version 8.

If you Skype, please upgrade it to the most recent version to resolve this vulnerability.

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Wireshark 2.4.5 and 2.2.13
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v2.4.5: 9 CVEs (defined) resolved

v2.2.13: 8 CVEs resolved

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 (v2.4.5) or v2.2.13). 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