Tag Archives: SMB

Mitigating Microsoft’s June 2019 NTLM Vulnerabilities

Microsoft issued an update yesterday to resolve 2 vulnerabilities within Windows that can be used to allow an attacker to authenticate and run code remotely.

TL DR: Install the updates for CVE-2019-1019 and CVE-2019-1040 and follow the recommend guidelines in Preempt’s blog post:

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If attackers exploited these issues; what would the result be?
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Preempt responsibly disclosed 2 vulnerabilities as a result of 3 logic flaws in NTLM to Microsoft. As a result of previous disclosures Microsoft added the Message Integrity Code (MIC) field designed to guarantee that attackers cannot tamper with NTLM messages in any way. Preempt bypassed this allowing them to change NTLM authentication fields, reducing security.

Next; Server Message Block (SMB) Session Signing was bypassed by Preempt allowing attackers to relay NTLM authentication messages and establish SMB and DCE/RPC sessions. Enhanced Protection for Authentication (EPA) was bypassed allowing the altering of “NTLM messages to generate legitimate channel binding information.” Finally, their bypasses could allow “attackers to relay NTLM authentication requests to any server in the domain, including domain controllers, while establishing a signed session to perform remote code execution.” This potentially could lead to the entire Active Directory domain becoming compromised by moving laterally from system to system.

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How can an organisation or a consumer/end-user defend against these attacks/bypasses?
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Install the updates for CVE-2019-1019 and CVE-2019-1040:

Moreover; Preempt’s blog post provides the necessary recommendations to fully mitigate these issues.

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For reference I have linked to how to enable the following mitigations:

Enforce SMB Signing

Block NTLMv1
Part 1

Further information link

Enforce LDAP Signing

Enforce EPA:
Part 1

Part 2

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

Thank you.

April 2019 Update Summary

Yesterday Microsoft and Adobe made available their scheduled security updates. Microsoft addressed 74 vulnerabilities (more formally known as CVEs (defined)) with Adobe resolving 42 vulnerabilities.

Adobe Acrobat and Reader: 21x priority 2 vulnerabilities (11x Critical and 10x Important severity)

Adobe Flash: 2x priority 2 vulnerabilities (1x Critical and 1x Important severity)

Adobe Shockwave Player: 7x priority 2 vulnerabilities (7x Critical severity)

Adobe Dreamweaver: 1x priority 3 vulnerability (Moderate severity)

Adobe XD: 2x priority 3 vulnerabilities (2x Critical severity)

Adobe InDesign: 1x priority 3 vulnerability (Critical severity)

Adobe Experience Manager Forms: 1x priority 2 vulnerability (Important severity)

Adobe Bridge CC: 8x priority CVEs (2x Critical, 6x Important)

If you use Acrobat/Reader, Flash or Shockwave, please apply the necessary updates as soon as possible. Please install their remaining priority 2 and 3 updates when you can.

Please note; as per Adobe’s notice Shockwave Player has now reached it’s end of life. No further updates will be made available.

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For Microsoft; this month’s list of Known Issues is available within their monthly summary page and applies to all currently supported operating systems. All issues however do have at least 1 workaround:

4487563                Microsoft Exchange Server 2019, 2016, and 2013

4491413                Update Rollup 27 for Exchange Server 2010 Service Pack 3

4493441                Windows 10 version 1709, Windows Server Version 1709

4493446                Windows 8.1, Windows Server 2012 R2 (Monthly Rollup)

4493448                Windows 7 Service Pack 1, Windows Server 2008 R2 Service Pack 1 (Security-only update)

4493450                Windows Server 2012 (Security-only Rollup)

4493451                Windows Server 2012 (Monthly Rollup)

4493458                Windows Server 2008 Service Pack 2 (Security-only update)

4493464                Windows 10 version 1803, Windows Server Version 1803

4493467                Windows 8.1, Windows Server 2012 R2 (Security-only update)

4493470                Windows 10 version 1607, Windows Server 2016

4493471                Windows Server 2008 Service Pack 2 (Monthly Rollup)

4493472                Windows 7 Service Pack 1, Windows Server 2008 R2 Service Pack 1 (Monthly Rollup)

4493474                Windows 10 version 1703

4493509                Windows 10 version 1809, Windows Server 2019

4493730                Windows Server 2008 SP2

4493435                Internet Explorer Cumulative Update

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:

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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:
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Win32k: CVE-2019-0803CVE-2019-0859 (both are being actively exploited in the wild)

Scripting Engine: CVE-2019-0861 ,  CVE-2019-0806 , CVE-2019-0739 , CVE-2019-0812 , CVE-2019-0829

Microsoft Graphics Component (GDI+): CVE-2019-0853

Microsoft Windows IOleCvt Interface: CVE-2019-0845

Microsoft Windows SMB Server: CVE-2019-0786

Microsoft (MS) XML: CVE-2019-0790 , CVE-2019-0791 , CVE-2019-0792 , CVE-2019-0793 , CVE-2019-0795

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 per standard best practice; 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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Notepad++:
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As noted in the March Update Summary post (due to a critical regression for the version that was released in March) 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.

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Wireshark 3.0.1 and 2.6.8
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v3.0.1: 10 security advisories

v2.6.8: 6 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 (v3.0.1 or v2.6.8). 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.

Adobe Reader Vulnerability Disclosed

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Updated: 26th February 2019
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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.

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Original Post
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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.

April 2018 Update Summary

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Update: 5th April 2018:
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On the 3rd of April, Microsoft released an out of band security update for the Microsoft Malware Protection Engine. Further details are available in this separate blog post.

Other updates made available by Microsoft for the Spectre Variant 2 vulnerability are:

kb4073119

kb4093112

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.

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Separately Microsoft have since issued an update, KB4099950 to resolve the issue detailed below affecting the network adapter on Windows 7.

The new update KB4099950 must be installed before KB4088875 and KB4088878 (I assume if this is not the case that KB4088875 and KB4088878 could be uninstalled first?)

If you were experiencing any of the following issues on Windows 7 or Windows Server 2008 R2, please install the above update to resolve them:

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A new Ethernet Network Interface Card (NIC) that has default settings may replace the previous NIC and cause network issues.

Static IP address setting are lost.

These symptoms may occur on both physical computers and virtual machine that are running VMware.
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Thank you.

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Update: 1st April 2018:
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Microsoft have issued an out of band update for Windows 7 SP1 64 bit and Windows Server 2008 R2 SP1 64 bit to resolve a regression (an un-intentional coding error resulting in a previously working software feature no longer working, alternative definition here) which introduced an additional elevation of privilege (defined) security vulnerability in the kernel (defined) of these Windows version, please see my new post for further details.

This post has also been updated with further software releases (please see below).

If you have already checked for updates and are not seeing any being offered for your Windows 7 or Windows 8.1 system, please ensure your anti-malware software is up to date. This article explains why this change was implemented by Microsoft. It also provides recommendations of how to resolve the issue of no updates being available. Windows 10 is not affected by this issue.

A known issue of a second network adapter appearing within Windows 7 has also been documented. If this occurs for you with March’s updates, this news article may be of assistance in resolving it. It is anticipated that Microsoft will resolve this issue in this month’s upcoming security updates.

Thank you.

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Original post:
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On Tuesday, 10th April Microsoft made available their scheduled security updates to resolve 63 vulnerabilities assigned to the same number of CVEs (defined). Microsoft have provided further details are provided within their Security Updates Guide.

There are 3 knowledge base articles detailing potential issues (some of which are pending resolutions) you may experience upon installing these updates. They are listed below for your reference:

4093112

4093118

4093108

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

Alongside these updates; Adobe released updates for the following products:

Adobe ColdFusion (priority 2, 5x CVEs)

Adobe Digital Editions (priority 3, 2x CVEs)

Adobe Experience Manager (priority 3, 3x CVEs)

Adobe Flash Player v29.0.0.140 (priority 2, 6x CVEs)

Adobe InDesign CC (priority 3, 2x CVEs)

Adobe PhoneGap Push Plugin (priority 3, 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. 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 will be phased out on the 20th of April):
—————
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. A useful list of all CVEs for this month is present here:
====================

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 Graphics Component consisting of the following 6 CVEs:

CVE-2018-1009

CVE-2018-1010

CVE-2018-1012

CVE-2018-1013

CVE-2018-1015

CVE-2018-1016

Microsoft Wireless Keyboard 850 Security Feature Bypass Vulnerability : described in more detail here.

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

Separately AMD have issued microcode (defined) updates for Windows 10 Version 1709 to enhance the protection of their customer’s against variant 2 (CVE-2017-5715) of the Spectre vulnerability. Further details of these updates are available within these KB articles: KB4093112 and KB3073119

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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Apple Security Updates:
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In late April Apple released updates for Safari, macOS and iOS:

Apple iOS v11.3.1

Apple Safari v11.1

Apple macOS High Sierra v10.13.4

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Please see these links from Apple for advice on backing up your iPhone and iPad.

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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7-Zip 18.05
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In late April; version 18.05 of 7-Zip was made available resolving one security vulnerability in it’s RAR packing code. Further details are provided in this linked to blog post.

Other highlights include the inclusion of ASLR on the 32 bit version and high entropy (HE)(defined here and here) ASLR (defined) on the 64 bit version. While the above blog post mentions HEASLR is not enabled, when I tested it with Process Explorer it was showing HEASLR as enabled. That blog post also describes how to add Arbitrary Code Guard (ACG) (defined) protection for 7-Zip on Windows 10. Version 18.01 and later also come with Data Execution Prevention (DEP)(defined here and here).

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. If you use these software applications or 7-Zip by itself, please update these installed applications to benefit from the resolved vulnerability and the new mitigations.

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Wireshark 2.4.6 and 2.2.14
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v2.4.6: 10 security advisories

v2.2.14: 8 security advisories

The security advisory wnpa-sec-2018-24 applicable to both of the above versions resolves 10 memory leaks (defined).

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 (v2.4.6) or v2.2.14). 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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Wireshark 2.6.0
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While this update is not listed as a security update; it is the latest version of Wireshark within the Stable release channel. The older 2.4.x version did not receive a further update. It is very likely version 2.6 will be required to receive future security updates. Further details are available in the release notes of version 2.6. If possible, please consider upgrading to this version in the near future.

Further installation tips are provided above (as per version 2.4.6 and 2.2.14).

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Oracle:
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Oracle issued updates to resolve 254 vulnerabilities. Further details and installation steps are available here. 14 vulnerabilities affect the Java runtime. 12 of these are remotely exploitable without an attacker needing to obtain a user’s username and password (their credentials).

If you use any of the Oracle products listed here, please install the appropriate security updates as soon as possible.

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OpenSSL
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In mid April; the OpenSSL Foundation issued updates for OpenSSL to address 1x low security vulnerability detailed in this security advisory. To resolve this please update your OpenSSL installations to 1.1.0i or 1.0.2p (as appropriate).

FTP mirrors to obtain the necessary downloads are available from here.

Downloadable Tarballs (compressed/packaged code made for distribution) are available from here.

It should also be possible to use the package manager of a Linux/Unix operating system to update your OpenSSL installation as mentioned within the section titled “Installing updates for Linux distributions” on the “Protecting Your PC” page of this blog.

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A Closer Look at CVE-2018-0950
=======================
While Microsoft have addressed the vulnerability designated as CVE-2018-0950 (defined) this month; Will Dormann, a security researcher with the CERT Coordination Center has demonstrated further mitigations (defined) you may wish to take. These mitigations (listed at the end of his in-depth discussion) will better defend your system(s) against a variant of this vulnerability which still remains relatively easy for an attacker to exploit.

Thank you.

Responding to Wana Decrypt0r / WanaCrypt0r Infections

As I am sure you are aware earlier this week a new variant of ransomware named WanaCrypt0r began to infect many systems worldwide using the vulnerability patched in March 2017. The infections were especially severe in the UK (hospitals were affected), Spain (banks, the ISP Telefonica and gas/electricity providers) among many others. The infections were spreading in a worm (defined) like fashion.

The ransomware uses the vulnerability exploited by the “Eternal Blue” exploit patched by Microsoft in Mach by their MS17-010 update. This exploit uses the SMBv1 (defined) protocol to enter a vulnerable system over port 445 (when that port is accessible from the internet). In some instances the CERT of Spain have observed the exploit installing the DoublePulsar malware on the already infected system. A live map of this malware’s global infections is available here. Once the malware obtains access to your system it installs the WanaCrypt0r ransomware to encrypt your files. As detailed by BleepingComputer it also terminates active databases and email servers so that it can encrypt them also.

On the 12th of May, the spread of the malware was temporarily halted by the actions of the malware researcher known as MalwareTech. They registered a website domain the malware checks if it exists while installing itself on your system. If it exists, it halts its installation and doesn’t encrypt your data (acting like a “kill switch”). I use the word temporary above since as the researcher points out all the malware authors need to do is to choose a different domain and re-release the updated malware (or worse they could use a domain generation algorithm (DGA)(defined) to make registering the websites by researchers even harder). The purpose of the malware checking if this domain was registered is to check if it is running inside a malware sandbox (defined).

How can I protect myself from this threat?
If you have not already done so, please install the MS17-010 security update (released in March 2017) on your Windows based servers and workstations. Researchers are simply saying “patch your systems” and that is what they mean. Microsoft discusses this advice in more detail in their MSRC blog post.

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Note:
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A full list of the versions of Windows affected by vulnerabilities patched within MS17-010 is provided at the end of this post.

If you are not sure how to update your systems, the following links below will assist if you are consumer/small business. Larger corporations should check with their IT team/system administrators install this update. If you can, please install all other remaining security updates:

Windows Vista
http://windows.microsoft.com/en-us/windows-vista/Turn-automatic-updating-on-or-off

Windows 7
http://windows.microsoft.com/en-US/windows7/products/features/windows-update

Windows 8.1
http://windows.microsoft.com/en-us/windows-8/windows-update-faq

Windows 10
http://pcsupport.about.com/od/keepingupwithupdates/f/windows-updates.htm

Microsoft have since released the MS17-010 update for all other remaining out of support Windows systems namely Windows XP, Windows Server 2003 and Windows 8.0. They are available as direct downloads from their MSRC blog post. I checked earlier today and these updates were not being offered by Windows Update and Automatic Updates for those older versions of Windows, please obtain the updates directly from their MSRC blog post.

While the “kill switch”for this malware was used (as mentioned above), it is very likely to return in the future. The steps below will better prepare you now and for the future.

I am aware Windows Vista is out of support at this time but it was supported when the MS17-010 update was released.

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Update: 15th May 2017:
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It is appears a new variant (Uiwix) of this threat is now circulating which does not have a kill switch. This variant does not appear to spread using a different vulnerability. Other variants are currently in-progress.

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Update: 18th May 2017:
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As mentioned above, newer variants of this malware are being made available. They exploit the same vulnerability as WannaCry but don’t spread in a worm like fashion.

I would suggest installing the MS17-010 as soon as possible since further ransomware is likely to capitalise on many devices (approximately 1 million still exposing the SMB protocol to the internet, with roughly 800k being Windows devices).

Moreover, the ShadowBrokers may release more exploits next month (and continue to do so on a regular basis) but this time we are unlikely to have security updates ready for them. My advice is to be prepared in June.

Thank you.
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Update: 21st May 2017:
======================
The Eternals Rocks worm is now also spreading by exploiting exposed systems over SMB. The advice below to block installation of WannaCrypt should prevent infection of your systems. At this time, the worm is not carrying out malicious actions with infected devices. Instead it is setting up a C&C (C2)(defined) infrastructure and may leverage this for malicious actions in the future.

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Bayer healthcare equipment was confirmed affected by WannaCry but service was restored in less than 24 hours. Other manufacturers have also issued security advisories:

Siemens

Smiths Medical

Medtronic

Johnson & Johnson

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The US ICS CERT have issued an alert with recommendations for critical infrastructure devices. Affected vendors include those mentioned above and GE, Philips, Tridium, Emerson Automaton Solutions, Schneider Electric (among others).

Please note the above link for the ICS CERT advisory is https://ics-cert.us-cert.gov/alerts/ICS-ALERT-17-135-01D If this advisory is updated it will become https://ics-cert.us-cert.gov/alerts/ICS-ALERT-17-135-01E Further updates will change the final letter to F, G and so on.

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ICS CERT also issued an FAQ on WannaCry which you may find useful.
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Additional advice/considerations:
At this time there is no known way to decrypt your files if you have been effected by the WanaCrypt0r ransomware. If you have the option of restoring your files from a backup, please do so. Your only other option is discussed by BleepingComputer at the end of this article.

If you followed the advice earlier in the week and turned off your systems before they were infected, that was a wise precaution. However when you power them back on you will need to avoid them becoming infected before you can secure them. A French security researcher had a honeypot (defined) of theirs infected 6 times in 90 minutes.

If you can segregate your vulnerable devices (including devices within your network perimeter) so they don’t expose the following ports:

  • TCP port 445 with related protocols on UDP ports 137-138
  • TCP port 139
  • Also disable SMBv1 (it’s a deprecated protocol)
  • Please also block the Remote Desktop Protocol (RDP) port 3389 (defined) at the entry point to your corporate to prevent the spread of this malware as recommended by the US CERT.

Once you have updated your Windows devices against this vulnerability, please by all means resume normal operations but follow the advice of the US CERT and avoid having the SMB port exposed to the internet going forward as a defense in-depth measure (defined)(PDF).

Other recommendations are as follows:

  • It’s important to understand, installing the update mentioned in this post will protect your Windows systems from spreading the ransomware to other systems. If you click on a link in a suspicious email (or another source) the ransomware may still be downloaded but will only encrypt/effect your system.
  • For any critical systems, ask if they really need to be connected to the internet or not? Avoid unnecessarily connecting them.
  • Provide your staff with security awareness training (defined)(PDF). This will prevent this malware infecting your systems by means of phishing (defined) (which can still encrypt your data even if you have installed the above recommended security update, that update only blocks the spreading of the infection). According to the US CERT and HelpNetSecurity this advice isn’t confirmed but it will not reduce your protection.
  • Verify your organization can recover from a ransomware attack like this as part of your Business continuity process (BCP)(defined)(PDF).
  • If you have an incident response team, verify their standard response process against a ransomware attack like this to ensure it is fit for purpose.

Thank you.

 

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Affected Windows versions:
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While the MS17-010 security bulletin lists which versions of Windows are vulnerable to this ransomware, I have listed them all below (this applies to all 32 and 64 bit versions of Windows listed below):

Windows XP (with Service Pack 3)

Windows Server 2003 (with Service Pack 2)

Windows Vista (with Service Pack 2)

Windows Server 2008 (with Service Pack 2)

Windows Server 2008 (with Service Pack 2)(Server Core installation)(defined)

Windows 7 (with Service Pack 1)

Windows Server 2008 R2 (with Service Pack 1)

Windows Server 2008 R2 (with Service Pack 1)(Server Core installation)

Windows 8.0

Windows 8.1 (with 8.1 Update (April 2014))

Windows Server 2012

Windows Server 2012 (Server Core installation)

Windows Server 2012 R2

Windows Server 2012 R2 (Server Core installation)

Windows RT 8.1

Windows 10 Version 1507

Windows 10 Version 1511

Windows 10 Version 1607

Windows Server 2016

Windows Server 2016 (Server Core installation)

DoublePulsar exploit: victim devices are widespread

Last month the hacking group known as the Shadow Brokers made available a set of exploits (this appears to be their last remaining set). These exploits allegedly came from the NSA. A full list of the exploits is available here. Microsoft’s analysis of the exploits made which applies to their products and which security updates resolve them are available here.

What is DoublePulsar and how does it affect a system?
The exploit from this recently released collection which targets the Windows SMB Server component of Windows is known as DoublePulsar. It is a kernel mode (or ring zero (defined)) exploit which provides an attacker with full control over an affected system as well as providing a backdoor (defined).

It is also allows the execution of shellcode (defined) and the downloading of further malware. A complete list of it’s capabilities is available from Symantec’s analysis.

This threat is being called similar to the MS08-067 vulnerability from October 2008 which lead to widespread installation of the Conficker malware (which still persists today). That article estimates this vulnerability will be with us for many years to come. In my professional career I still see large numbers of servers and workstations not patched against the MS08-067 vulnerability even after all these years. The exploits made available by the Shadow Brokers have been made easy to use by others posting YouTube videos and documentation of how to use them. Security researchers are tracking the spread of this malware here , here and here.

How can I protect myself from this threat?
Preventing a compromise by this threat:

If your servers or workstations have Windows Server 2008 or Windows Vista (respectively) or newer installed, please install Microsoft’s security update MS17-010 as soon as possible. As a defense in-depth measure (defined)(PDF), please also consider blocking port 445 from being accessed externally (since this is unlikely to be the last SMB exploit we see).

Please note, Windows Vista systems are also no longer supported and you should consider upgrading (if you are not already in the process of doing so). Windows Server 2008 will be supported until the 13th of January 2020.

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Update: 19th May 2017:
=======================
With the rapid propagation of the WannaCry ransomware, Microsoft made available the MS17-010 update for Windows XP, Windows Server 2003 and Windows 8.0. The updates for these out of support operating systems are available from Microsoft’s blog post.

Once the update is installed, if your servers or workstations have Window Server 2003 or Windows XP (respectively) installed, please block port 445 (the Windows SMB protocol port) from being accessed from an external network (as previously recommended by US-CERT and mentioned in a past blog post of mine).

In addition to blocking port 445 as mentioned above, I would also suggest the following:

If you can, segregate your vulnerable devices (including devices within your network perimeter) so they don’t expose the following ports:

  • TCP port 445 with related protocols on UDP ports 137-138
  • TCP port 139
  • Also disable SMBv1 (it’s a deprecated protocol)
  • Please also block the Remote Desktop Protocol (RDP) port 3389 (defined) at the entry point to your corporate to prevent the spread of this malware as recommended by the US CERT.

To check if your system has been compromised by Double Pulsar, you can use this tool.

Removing the threat from a compromised system:
You can remove the infection simply by shutting the system down since the malware does not persist after a reboot. You can then patch the vulnerability and block access to port 445 to prevent the malware from returning (both as mentioned above).

Thank you.

US CERT Warns of Possible SMB Zero Day Vulnerability

Earlier this month saw the end of operations for a group known as the Shadow Brokers (who were responsible for the disclosure of critical security vulnerabilities in enterprise networking infrastructure). Their online auction of exploits remains open.

Among the exploits for sale is a possible zero day (defined) SMB (defined) exploit for Windows. With the potential use of this exploited predicted, the US-CERT issued a security advisory, which suggested disabling SMB version 1 and disabling the use of SMB version 2 at the network perimeter (preventing external access or internal traffic reaching outside of the corporate network). As previously noted on this blog, securing the use of SMB version 2 in this manner will also protect against the Redirect to SMB vulnerability.

These recommendations should better secure your corporate network against this exploit as well as future vulnerabilities.

Thank you.