Tag Archives: Microsoft

WPA2 KRACK Vulnerability: What you need to know

Last Sunday, the early signs of a vulnerability disclosure affecting the extensively used Wi-Fi protected access (WPA2) protocol were evident. The next day, disclosure of the vulnerability lead to more details. The vulnerability was discovered by  two researchers Mathy Vanhoef and Frank Piessens of the Katholieke Universiteit Leuven (KU Leuven) while examining OpenBSD’s implementation of the WPA2 four way handshake.

Why should this vulnerability be considered important?
On Monday 16th October, the KRACK (key re-installation attacks) vulnerability was disclosed. This vulnerability was found within the implementation of the WPA2 protocol rather than any single device making it’s impact much more widespread. For example, vulnerable devices include Windows, OpenBSD (if not already patched against it), Linux, Apple iOS, Apple macOS and Google Android.

If exploited this vulnerability could allow decryption, packet replay, TCP connection hijacking and if WPA-TKIP (defined) or GCMP (explained) are used; the attacker can inject packets (defined) into a victim’s data, forging web traffic.

How can an attacker exploit this vulnerability?
To exploit the vulnerability an attacker must be within range of a vulnerable Wi-Fi network in order to perform a man in the middle attack (MiTM)(defined). This means that this vulnerability cannot be exploited over the Internet.

This vulnerability occurs since the initial four way handshake is used to generate a strong and unique key to encrypt the traffic between wireless devices. A handshake is used to authenticate two entities (in this example a wireless router and a wireless device wishing to connect to it) and to establish the a new key used to communicate.

The attacker needs to manipulate the key exchange (described below) by replaying cryptographic handshake messages (which blocks the message reaching the client device) causing it to be re-sent during the third step of the four way handshake. This is allowed since wireless communication is not 100% reliable e.g. a data packet could be lost or dropped and the router will re-send the third part of the handshake. This is allowed to occur multiple times if necessary. Each time the handshake is re-sent the attacker can use it to gather how cryptographic nonces (defined here and here) are created (since replay counters and nonces are reset) and use this to undermine the entire encryption scheme.

How can I protect myself from this vulnerability?
AS described in this CERT knowledge base article.; updates from vendors will be released in the coming days and weeks. Apple (currently a beta update) and Microsoft already have updates available. OpenBSD also resolved this issue before the disclosure this week.

Microsoft within the information they published for the vulnerability discusses how when a Windows device enters a low power state the vulnerable functionality of the wireless connection is passed to the underlying Wi-Fi hardware. For this reason they recommend contacting the vendor of that Wi-Fi hardware to request updated drivers (defined).

Links to affected hardware vendors are available from this ICASI Multi-Vendor Vulnerability Disclosure statement. Intel’ security advisory with relevant driver updates is here. The wireless vendor, Edimax also posted a statement with further updates to follow. A detailed but easy to use list of many vendors responses is here. Since I use an Asus router, the best response I could locate is here.

======
Update: 21st October 2017:
Cisco have published a security advisory relating to the KRACK vulnerability for its wireless products. At the time of writing no patches were available but the advisory does contain a workaround for some of the affected products.
======

The above updates are software fixes but updates will also be made available for devices in the form of firmware updates e.g. for wireless routers, smartphones and Internet of Things (IoT)(defined) devices. For any wireless devices you own, please check with the manufacturer/vendor for available updates with the above CERT article and vendor response list detailing many of the common vendors.

Thank you.

Infineon TPM Chips Patched Against Disclosed Vulnerability

With the release of Microsoft’s security updates last week; Infineon published a security advisory relating to a vulnerability discovered by security researchers in 2012.

Why should this vulnerability be considered important?
The vulnerable hardware is mostly to be found within corporate computers from manufacturers such as HP, Fujitsu and Lenovo. Google Chromebooks, routers and some Internet of Things (IoT)(defined). The vulnerability allows an attacker to determine a private (defined) encryption key when it has been generated by a vulnerable TPM (Trusted Platform Module) using only the public key (defined). Once the private key has been obtained it can be used by an attacker to decrypt the contents of a Microsoft BitLocker encrypted hard drive, to digitally sign fake software releases, to sign malware (making it appear more legitimate) as well impersonating the legitimate owner of the private key.

This vulnerability also affects cryptographic smart cards, security tokens and other secure hardware chips manufactured by Infineon. An estimate 760k devices are thought to be vulnerable while the true number could be up to three times that amount.

While the researchers were able to verify an attacker could derive the private key from 1024 and 2048 but public key, they were unable to do so for 4096 bit key since “a 4096-bit RSA key is not practically factorizable now, but “may become so, if the attack is improved.” For 1024 and 2048 bit keys, the factorisation can be easily parallelised by x number of CPUs, reducing the time taken by x times (where x is the number of cores a CPU has) allowing completion in hour or days.

How can I protect myself from this vulnerability?
Microsoft’s advisory provides the recommended steps for systems using Windows or other Microsoft products e.g. Active Directory Certificate Services (ADCS), Active Directory Directory Services (ADDS) (among others). The updates they recommend are only a workaround for the vulnerability. The vulnerability must still be resolved by applying updates to the vulnerable TPM chips. This advice also includes clearing the TPM and re-generating the necessary keys only after applying the updates from Microsoft.

Similarly Google made available Chrome OS M60 to mitigate this vulnerability. Further links to other affected vendors are listed below:

Fujitsu

HP Customer Support

HP Enterprise Support

Lenovo

Toshiba

Thank you.

Microsoft Ends Support for Windows Vista

As detailed in the news online Microsoft is ending the support lifecycle of Windows Vista today. It will no longer receive security updates going forward.

With the installation share of Windows Vista being only approximately 1% of all installed operating systems, the number of users/systems affected is small. However they should still seriously consider migrating to newer operating systems and possibly newer hardware to support their new choice of operating systems.

Since this is a consumer oriented operating system, the recommendations previously provided for Windows Server 2003 do not apply here. Check if your current applications are compatible with newer operating systems and migrate at your earliest convenience to minimise future since the support lifecycle has ended.

Thank you.

Disclosed Microsoft Zero Day Under Attack By APT Group

====================
Update: 8th November:
The Microsoft zero day vulnerability discussed in this post has now been patched. Please refer to this post for the appropriate information and download links.

Thank you.

====================
Original Post:
====================
Earlier this week Google publicly disclosed (defined) details of a new zero day (defined) vulnerability affecting supported versions of Windows up to Windows 10. Fortunately, the disclosure only included minimal details.

Why Should These Issues Be Considered Important?
The vulnerability disclosed by Google could result with an attacker being able to elevate their privileges (defined) on an affected system. However, when used in combination with a previously patched Adobe Flash Player vulnerability (reference previous post) this could result in a Windows system under your responsibility or in your ownership to have a backdoor (defined) installed.

Some good news is that this new exploit primarily targets organisations that operate in the following sectors (thus all other organisations are at somewhat reduced risk): government, intelligence or military organisations.

The nature of the backdoor is the decision of the attacker but would usually include a means of remaining persistent on the system and allowing the attacker to remote access the infected system. This backdoor can then be used to move data of the attacker’s choice off the affected system. The APT group known as STRONTIUM by Microsoft (other aliases used in the wider cyber security industry are APT28, also aka Sofacy aka Fancy Bear aka TsarTeam aka Sednit aka PawnStorm). STRONTIUM is also known for moving laterally throughout the network which they compromise (where the pass the hash (PtH) (defined) technique is the method of choice to do so).

How Can I Protect Myself From This Issue?
While a patch from Microsoft is in progress (scheduled for release on the 8th of November): follow safe email guidelines namely don’t click on unexpected/unsolicited links or open potentially dangerous email attachments to prevent the execution (carrying out of) the exploits actions in the first instance.

If you use the Microsoft Edge or Google Chrome web browsers the exploit for the local elevation of privilege vulnerability will be mitigated. This is due to Chrome’s sandbox (defined) blocking the use of API (defined) calls to the win32k.sys driver (defined). This in addition to its existing mitigations when installed on Windows 10 which I previously discussed.

Microsoft Edge on the other hand implements Code Integrity to prevent the next steps of exploitation.

To protect endpoints within your organisation you could consider utilising the logging capabilities of Microsoft EMET and Systinternals’ Sysmon by processing their logs using a SIEM (defined) and taking action when that SIEM a alerts you to suspicion activity. This is especially true since this exploit can occur from within web browsers, the Java JRE, Microsoft Word and Microsoft PowerPoint (namely that these applications are used to open suspicious/untrusted files).

My thanks to a colleague (you know who you are!) for compiling very useful information for this blog post.

Thank you.

September 2016 Security Updates Summary

Earlier today Microsoft and Adobe released their scheduled monthly security updates.

Microsoft’s updates consist of 14 security bulletins. These bulletins address 50 vulnerabilities more formally known as CVEs (defined)(not including the Adobe vulnerabilities mentioned below).

Only the Internet Explorer security bulletin currently lists a Known Issue (discussed below). However as always please double check the IT Pro Patch Tuesday blog to ensure that there are no issues being experienced before you begin installing the new updates. At this time it does not list any Known Issues.

Update: 15th September 2016:

It has been reported that the security updates for Internet Explorer MS16-104 and Microsoft Edge (MS16-105) patches a zero-day (defined) vulnerability that has been publicly exploited. Further details of this vulnerability have since been disclosed and are available in this ThreatPost article.

The Known Issue for this update now mentions “Microsoft is aware of limited issues in which an ActiveX install may fail when using the ActiveX Installer Service (AXIS) with Internet Explorer 10 or Internet Explorer 11.” However, at this time no workaround or solution is available.

Moreover, the Microsoft Office security bulletin resolves an Important severity level ASLR (defined) bypass designated CVE-2016-0137 within the Microsoft Detours DLL (defined) that applications such as Microsoft App-V use. This issue has the potential to affect a lot of other 3rd party products and is discussed in more detail in this ThreatPost article. Further information/resources concerning this vulnerability are available on this GitHub page. A possibly related issue was found in Nvidia’s graphics driver (defined) (within detoured.dll) late last year which they issued a patch for.

This month also marks the final month that Windows 7 and Windows 8.1 will receive security updates packaged in the traditional format. From October the updates will be offered in packages similar to that of Windows 10 which will mean fewer individual updates will need to be installed to bring systems up to date. The updates will also replace updates from previous months again reducing the volume of updates needing to be installed. There will be single security and reliability updates.

While I am in favour of the simplification of updates, the “Known Issues” that I mention each month will become even more important since you won’t have the option of choosing which updates to install. This will lead to more outages and compatibility issues especially for corporate environments which is discussed in this article. Microsoft provides more details of these changes in their Windows IT Pro blog post. This additional Microsoft blog post and this Windows IT Pro blog post provide further coverage.

Further to this, next month Microsoft plans to begin to block out dated versions of Adobe Flash Player ActiveX controls (defined). Further details are available in their blog post.

====================
For Adobe’s scheduled released they made available an updated version of Flash Player that addresses 29 priority 1 vulnerabilities.

Depending on which version of Flash Player you have, please review the Adobe security bulletin or Microsoft bulletin as appropriate and apply the recommended updates. Google Chrome users will have the updated installed automatically alongside the updated version of Google Chrome released today.

Adobe also released a security bulletin for Adobe AIR SDK and compiler (AIR is its application runtime) to address a single priority 3 vulnerability. More information as well as installation steps are available in the relevant security bulletin. Finally, Adobe released a security bulletin for Digital Editions that addresses 8 priority 3 vulnerabilities.

If you use any of these products, please review the security bulletins linked to above and apply the necessary updates.

You can monitor the availability of security updates for the majority of your software from the following websites (among others) or use Secunia PSI:

—————
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 Software, Security 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 making a donation.

—————
If you use any of the above software, please install the appropriate updates as soon as possible. Steps for installing updates for Windows are provided on the “Protecting Your PC” page.

To assist with making the best use of your time when deploying these updates, I will prioritise the updates for you below:

With Adobe’s Flash Player update (to version 23.0.0.162) addressing 29 critical vulnerabilities, this should be installed first if you already have a previous version installed.

For the Microsoft updates, for corporate environments/server operating systems please first install the Microsoft Exchange update (if you use it within your environment). This should be followed by Microsoft Office, Security Update for Windows (MS16-110) and the Microsoft Graphics Component.

For desktop workstations / small business environments please make Internet Explorer, Microsoft Edge, Microsoft Office and the Microsoft Graphics Component your first priorities due to their severities and prevalent use. The remaining security updates can be installed when you have the time to do so. Detailed information on the contents of each security bulletin is available in this Computerworld article (a new article is published each month within their Patch Tuesday Debugged column).

Another security pre-caution that you may wish to take if you have Microsoft EMET (please ensure your version of EMET is the most recent version 5.5) installed is to use it to protect you from Adobe Flash being used to exploit vulnerabilities when you open a Microsoft Office document or Adobe PDF file. I provide recommendations of how to do this at the end of the July 2015 Update Summary.

As always as a routine precaution I would recommend backing up the data on any device for which you are installing updates in order to prevent data loss in the rare event that any update causes unexpected issues.

Thank you.

August 2016 Security Updates Summary

Yesterday was Microsoft’s Update Tuesday and they made available their scheduled monthly security updates.

Microsoft’s updates consist of 9 security bulletins. These bulletins resolve 33 vulnerabilities more formally known as CVEs (defined).

Microsoft’s Security bulletin summary lists Known Issues for bulletins MS16-100 (Update for Secure Boot, kb3179577) and MS16-101 (Security update for Windows authentication methods, kb3178465).

The first issue is more informational rather than an error/interruption to your work. While the second known issue is notifying you that this update “disables the ability of the Negotiate process to fall back to NTLM when Kerberos authentication fails for password change operations”.

The IT Pro Patch Tuesday blog is also a very useful resource to check before installing the updates to better inform you of whether to proceed or not.

====================
For the first time since January Adobe has not published a Flash Player security bulletin. However, they did release a priority 2 update for Adobe Experience Manager, resolving 4 CVEs.

If you use any the above Adobe products, please review the security bulletins linked to above and apply the necessary updates as soon as possible.

====================
You can monitor the availability of security updates for the majority of your software from the following websites (among others) or use Secunia PSI:

—————
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 Software, Security 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 making a donation.

—————
If you use any of the above software, please install the appropriate updates as soon as possible. Steps for installing updates for Windows are provided on the “Protecting Your PC” page.

To assist with making the best use of your time when deploying this month’s Microsoft updates, I will prioritise the updates for you below:

Please make the updates for Microsoft Office, Microsoft Internet Explorer, Microsoft Edge your first priorities since they all address critical severity vulnerabilities. Please follow these with the Microsoft Graphics Component update (since it addresses a critical font handling issue (font vulnerabilities are discussed in a previous blog post)). All remaining security updates can be installed when you have the time available.

A final security pre-caution that you may wish to take if you have Microsoft EMET (please ensure your version of EMET is the most recent version 5.5) installed is to use it to protect you from Adobe Flash being used to exploit vulnerabilities when you open a Microsoft Office document or Adobe PDF file. I provide recommendations of how to do this at the end of the July 2015 Update Summary.

As always as a routine precaution I would recommend backing up the data on any device for which you are installing updates in order to prevent data loss in the rare event that any update causes unexpected issues.

Thank you.

July 2016 Security Updates Summary

Earlier today Microsoft released their scheduled monthly security updates.

Microsoft’s updates consist of 10 security bulletins (not including the Adobe Flash Player update (more details below)). These bulletins resolve 49 vulnerabilities more formally known as CVEs (defined).

Just like last month at the time of writing there are Known Issues for this month’s updates (although last month’s summary was later updated to include 3 Known Issues including the well-known issues with the Group Policy update). However please double check the IT Pro Patch Tuesday blog to ensure that there are no issues being experienced before you begin installing the new updates.

As I mentioned above one of Microsoft’s bulletins relates to Adobe’s Flash Player update. This update addresses a massive 52 critical CVEs.

For Windows 8.1 and later Microsoft have released a corresponding Adobe Flash security bulletin MS16-093. As expected, it includes the same fixes within the above mentioned Adobe bulletin.

Depending on which version of Flash Player you have, please review the Adobe security bulletin or Microsoft bulletin as appropriate and apply the recommended updates. Google Chrome users should have the updated version installed automatically alongside the updated version of Chrome.

Adobe also released a large security update for Adobe Acrobat DC, Acrobat XI, Acrobat Reader DC and Adobe Reader XI addressing 30 CVEs within those products. These vulnerabilities have been classified as critical but have been assigned Priority 2 by Adobe, meaning that these updates should be installed sometime within the next 30 days. Further details of these updates are available in this security bulletin.

Finally, Adobe published an update for it’s XMP Toolkit for Java affecting versions prior to 5.1.2. Adobe has classified this as a priority 3 update that addresses an information disclosure issue.
====================
If you use any of the above Adobe products, please review the security bulletins linked to above and apply the necessary updates as soon as possible. This is especially true for Adobe Flash.

Whether you are an individual, a large or small organization you should be aim to deploy Flash updates within 1 week in order to reduce the possibility of being affected by exploit kits (defined) that may seek to take advantage of these newly disclosed issues.

You can monitor the availability of security updates for the majority of your software from the following websites (among others) or use Secunia PSI:
—————
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 Software, Security 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 making a donation.
—————
If you use any of the above software, please install the appropriate updates as soon as possible. Steps for installing updates for Windows are provided on the “Protecting Your PC” page.

To assist with making the best use of your time when deploying these updates, I will prioritise the updates for you below:

Please make the updates for Microsoft Office, Microsoft Internet Explorer, Microsoft Edge your first priorities since they all address critical severity vulnerabilities. Please follow these with Windows Print Spooler Components (please see this link for an explanation of why this update is of critical severity) and finally Microsoft Jscript and VBScript due to their severities and prevalent use. All remaining security updates can be installed when you have the time available.

Another security pre-caution that you may wish to take if you have Microsoft EMET (please ensure your version of EMET is the most recent version 5.5) installed is to use it to protect you from Adobe Flash being used to exploit vulnerabilities when you open a Microsoft Office document or Adobe PDF file. I provide recommendations of how to do this at the end of the July 2015 Update Summary.

As always as a routine precaution I would recommend backing up the data on any device for which you are installing updates in order to prevent data loss in the rare event that any update causes unexpected issues.

Thank you.