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:
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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.

Internet of Things malware destroys devices

In early April embedded devices powered by Google Android, Linux and FreeBSD (specifically the BusyBox distribution) mainly used as media players and routers came under attack from a previously unseen form of malware.

How does this malware affect compromised devices?
Once compromised the device will cease functioning within seconds; an attack being called a PDoS (Permanent Denial of Service). This occurs since the malware corrupts the devices internal storage and reduces the number of kernel (defined) threads (sequences of independent in progress tasks) from several thousand to just one, causing the devices in progress tasks/work load to halt. Security firm Radware demonstrated this result with a webcam.

How does this malware initially compromise a device?
Since early April four unique versions of this malware (dubbed BrickerBot) have emerged. The first version attempted to compromise Radware’s test device almost 2,000 times within four days with the attacks originating from all over the world. The second and more advanced version uses Tor (The Onion Router) to enable attacks to take place from the Dark web (a portion of the internet only accessible using the Tor network). This makes tracing the source of the attacks almost impossible.

Versions 3 targets further devices while version 4 was active during a very briefly and ceased its activity after 90 attempted attacks. Radware provide more details in their analysis.

The malwares authors seek to gain control of vulnerable devices by attempting to access them over the internet via the Telnet protocol (defined, which uses TCP and UDP ports 23) by entering commonly used usernames and passwords until successful. If your network contains routers or music/media devices using the BusyBox distribution they are potentially vulnerable to this malware. Attackers can use tools such as Shodan (defined) to locate vulnerable devices over the internet and begin an attack.

How can I protect my devices from this malware?
Radware provide five steps you can take to better secure your internet of things (IoT , defined) devices from this malware. They also suggest the use of an IPS (defined) in this related blog post. The above recommendations are especially important since unlike other malware where you can re-format a hard disk and re-install the operating system (defined), this malware permanently damages the device and it will require a replacement.

Thank you.

Punycode makes phishing harder to detect

In mid-April, security researcher Xudong Zheng publicly disclosed (defined) and provided a demonstration of a security vulnerability within popular web browsers e.g. Google Chrome, Mozilla Firefox and Opera which may be used in phishing (defined) attacks.

Why should this vulnerability be considered important?
This vulnerability is not the first of kind, e.g. a similar vulnerability exists in how the DNS protocol resolves device hostnames (defined) (when combined with Service Discovery (SD) provides the capability of network resource distribution beyond the reach of multicast normally limited by the MAC Bridge.
However this vulnerability has the potential to allow an attacker to lead you into clicking a legitimate looking link which may lead to an unexpected website (which an attacker can populate with content of their choice). This may happen since an attacker can send you a highly targeted email (i.e. spear phishing) which you may be expecting and inadvertently click an undesired link or enter login details into a legitimate looking website (following a link from such an email).

Mr. Zheng demonstrates how this vulnerability exploits how web browsers translate letters from other non-Latin languages into Latin letters. For example, he registered the website of apple.com which when visited actually displays the website of xn--80ak6aa92e.com but your web browser will still show apple.com This occurs due to the translation of non-Latin letters into Latin characters making use of Punycode (a recognized standard of the Internet Engineering Task Force).

How can I protect myself from this vulnerability?
While the conventional advice of hovering over any link before clicking to view its actual destination is not redundant it is now significantly less useful.

If you use a password manager which works with your web browser it will not enter your username/password into a website translated from its Punycode. For example, your Apple credentials would not be entered into xn--80ak6aa92e.com

Google has addressed this vulnerability with the release of Chrome version 58. Opera also resolved this issue. Mozilla is currently considering the best means to resolve this vulnerability (Firefox 53 mistakenly shows apple.com) . In the meantime; Mozilla Firefox users can use the steps mentioned at the end of this news article to mitigate this issue.

For any website important to you, please manually type its address into your web browsers address bar to visit the legitimate website. Using encrypted connections where possible is encouraged e.g. https://twitter.com or https://mail.google.com

Thank you.

April 2017 Security Updates Summary

As expected earlier today Microsoft and Adobe released their scheduled monthly security updates.

Microsoft’s set of updates are much lighter in volume this month addressing 45 vulnerabilities more formally known as CVEs (defined). These are detailed within Microsoft’s new Security Updates Guide.

This month sees four known issues listed for this months updates all relating to the AMD Carrizo processor experiencing an issue which prevents the installation of future Windows Updates. Microsoft states in all four knowledge base articles (listed below) they are aware of this issue and are working to resolve it in upcoming updates:

KB4015549
KB4015546
KB4015550
KB4015547

At the time of writing the IT Pro Patch Tuesday blog does not list any Known Issues (although it has not been updated since November 2016, I’m unsure why).

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Adobe issued five security bulletins today affecting the following products:

Adobe Campaign (1x priority 2 CVE)
Adobe Flash Player (7x priority 1 CVEs)
Adobe Acrobat and Reader (47x priority 2 CVEs)
Adobe Photoshop (2x priority 3 CVEs)
Adobe Creative Cloud Desktop (2x priority 3 CVEs)

The priority ratings are explained in this link. 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 version installed automatically later this week.

If you use any of the above-mentioned Adobe products, please review the security bulletins linked to above and apply the necessary updates. The Flash update should be installed as soon as possible since exploit kits (defined) tend to take advantage of newly disclosed vulnerabilities very quickly.

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 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 donating.

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Update: 8th May 2017:
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I wish to provide information on other notable updates from April 2017 which I would recommend you install if you use these software products:

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Skype: While the Skype update to version 7.34.0.102 was released in March; details of the vulnerability it addressed were not made public until April.
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Putty 0.69: while released in March; it contains important security changes. It is downloadable from here.
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Wireshark 2.2.6 and 2.0.12
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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 (v2.2.6) or v2.0.12). 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.
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Oracle:
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There was a record 299 vulnerabilities addressed by Oracle’s updates in April. Further details and installation steps are available here. A useful summary post from Qualys is here. Of the 299 fixes, 8 vulnerabilities were addressed in the Java runtime.

If you use any of the Oracle products listed here, please install the appropriate security updates as soon as possible.
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Mozilla Firefox:
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Firefox 53.0 and Firefox 53.0.2

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Mozilla Firefox ESR:
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Firefox ESR 45.9 and Firefox ESR 52.1.

Details of how to install updates for Firefox are here. If Firefox is your web browser of choice, please update it as soon as possible to resolve these security issues.

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Google Chrome:
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Google Chrome: includes 29 security fixes:

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 update to take effect.
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Adobe Coldfusion:
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Adobe Coldfusion: 2x priority 2 vulnerabilities resolved.

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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.

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For the Microsoft updates this month, I will prioritize the order of installation for you below:

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Critical severity:
Microsoft Office and Windows WordPad (due to a previously disclosed zero day vulnerability (defined))
Microsoft Edge
Internet Explorer
Microsoft .Net Framework
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Install the remaining updates at your earliest convenience.

As always you can find detailed information on the contents of each security bulletin within ComputerWorld’s 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 5.52) 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. Please note that Microsoft EMET will be out of support on the 31st of July 2018.

As is my standard 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.

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.

Tampered NSIS installers contain ransomware

In a blog post earlier this month Microsoft provided an in-depth analysis of a new technique in use by ransomware authors to disguise their attempts to hold your data for ransom.

What has made these newly disguised ransomware installers so successful?
These attack involve tampering with a Nullsoft Scriptable Install System (NSIS) installer (used in paid, free and open-source software such as VideoLAN VLC, Wireshark (among others)). In contrast to previously altered installers the attackers have removed their randomly named DLL (defined) which dramatically reduces the chance of detection due to far less code being present. Inclusions of non-malicious plugins, an uninstallation component and a legitimate .bmp image file for use with the installer help to divert attention away from the installer’s real purpose.

The installer instead contains an installation script which would usually automate the installation of the application for you. In this case however an obfuscated (defined here and here) script which calls the Win32API (API, defined) allows an attacker to allocate (make ready for use) an area in the computer’s memory in order to activate a small code fragment to decrypt the ransomware.

As detailed by Deep Instinct’s security researcher Tom Nipravsky; the script is sophisticated since it operates only in memory in addition to being multi-staged. Moreover the shell code (defined) uses a technique known as Heaven’s Gate which allows 64 bit shell code to make use of a 32 bit process (defined) which makes the work of security researchers more difficult since debuggers (defined) cannot easily handle a transition from one architecture to another. This also has the benefit of bypassing API hooks (defined) which are monitored by anti-malware software and makes use of system calls (defined) as opposed to API calls.

Moreover this ransomware uses a technique known as “process hollowing.” This occurs when an attacker creates a process in a suspended state (defined) but replaces it’s in memory code with code the attacker wishes to hide. Finally the attackers use an encrypted installer within NSIS which currently security vendors are unable to trace and is only decrypted when it is about to be used.

How can I protect myself from these threats?
Since the tampered NSIS installers originate from emails you should follow the advice from SANS with regards to email:

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Use Caution Opening Email Attachments – A common method cyber criminals use to hack into people’s computers is to send them emails with infected attachments. People are tricked into opening these attachments because they appear to come from someone or something they know and trust. Only open email attachments that you were expecting. Not sure about an email? Call the person to confirm they sent it.
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Source: https://www.sans.org/tip-of-the-day (date: 1st March 2017)

Microsoft encourages enterprise/corporate users to upgrade to Windows 10 and make use of its security features to defend against this threat.

Full disclosure: I don’t work for or on behalf of Microsoft nor do I wish to promote their products/services. I have simply provided a link to their advice for corporate users who may already have Windows 10 (or are considering upgrading) in order for them to better protect themselves against this and other threats using the security protections it offers.

Thank you.

“DoubleAgent” Vulnerability Disclosure: What you need to know

In late March a security vulnerability was disclosed by the Israeli security firm Cybellum. However this was no ordinary public disclosure as I will explain below. Apologies for the untimely nature of this blog post due to other commitments:

What made this disclosure different?
At first glance this disclosure appeared very serious. It discussed the use of the Microsoft Application Verifier present within Windows XP up to and including Windows 10. They detail the leveraging of this tool to add a customised verifier DLL (defined) to hijack any legitimate process (defined) within Windows.

They demonstrated this attack against anti-malware software specifically Norton Security (by Symantec) resulting in a rogue DLL being injected (defined here and here) into the Norton process (ns.exe as demonstrated within their YouTube video). Despite claims by Cybellum security firms such as Avira and Comodo have reported this attack cannot bypass the self-protection features within their products. The full list of capabilities this attack provides is within this news article.

Windows Internals expert; Alex Ionescu later revealed the researchers from Cybellum used his work concerning protected processes to create this exploit and this was already a known issue. As was pointed out in the Twitter timelines linked to below once an attacker has administrative control over your system they could simply uninstall your security software rather than trying to bypass rendering the threat of this exploit far less important/relevant.

Twitter Timeline 1
Twitter Timeline 2
Twitter Timeline 3
Twitter Timeline 4
Twitter Timeline 5

Does this disclosure only affect security software?
It’s important to note this attack potential affects all software on Windows rather than just security software. In addition the proof of concept (PoC) exploit requires no changes for any application you choose to attack. Security software was chosen since almost all systems have anti-malware software installed and their process names are trusted (and allowed within application white listed (defined) environments).

How can I protect myself from this exploit?
Since this attack requires administrative privileges (defined) on Windows to have the intended effect, using a standard user account for everyday use will mitigate this attack.

From the various statements issued by the affected anti-malware vendors (listed below) please ensure your anti-malware software is the latest version available to ensure this attack is ineffective.

Traditional defences such patching your operating system, your web browser and be cautious of the attachments you open will also reduce the risk posed by this attack.

NetworkWorld Anti-Malware Vendor Responses

Malwarebytes Anti-malware

Symantec Endpoint Protection

Symantec Endpoint Protection Affected Versions

Thank you.