Tag Archives: exploit

vBulletin Breach and 0day – Daily Security Byte EP. 171

The creators of vBulletin are having a bad week. Not only did they have a data breach that resulted in around 400,00 stolen user records, but it sounds like the attacker leveraged a zero day vulnerability in their own software to compromise their network. Watch today’s Daily Byte to learn more about this story, and what you should do if you use vBulletin software.

(Episode Runtime: 2:10)

Direct YouTube Link: https://www.youtube.com/watch?v=5XIwY4seah0

EPISODE REFERENCES:

— Corey Nachreiner, CISSP (@SecAdept)

Drone Hacking – Daily Security Byte EP. 160

This week a research team found vulnerabilities in a remote control  communication protocol that would allow them to crash or ground quadcopters. What does hacking a drone have to do with information security? Watch today’s video to find out.

(Episode Runtime: 2:27)

Direct YouTube Link: https://www.youtube.com/watch?v=fcCtAdYorrY

EPISODE REFERENCES:

— Corey Nachreiner, CISSP (@SecAdept)

Don’t Be ‘fraid of No GHOST; Glibc Vulnerability

GHOST VulnerabilityDuring the blog downtime, observant security practitioners probably read about a serious new vulnerabilities called GHOST, which affects all Linux-based systems to some extent. I actually covered GHOST already, in one of my Daily Security Bytes, but you may have missed it during the downtime. Let me recap the issue here.

GHOST is the name Qualys gave to a newly reported security vulnerability in the very common glibc component that ships with almost all Linux-based software and hardware. If you haven’t heard of glibc, it’s the common GNU C library which contains functions that many Linux program rely on to do common task (such as looking up IP addresses). In a routine audit, Qualys researchers found that part of the gethostbyname() function suffers from a buffer overflow flaw that attackers can use to execute code on your Linux systems.

Because many different Linux application may (or may not) use this glibc function to look up IP addresses, this flaw might get exposed through almost any network service or package. Qualys specifically designed a Proof-of-Concept (PoC) exploit against the Exim email server, which attackers can exploit just by sending email, but they warn that many other Linux packages use the vulnerable function. Some potentially affected packages include:

  • apache
  • cups
  • dovecot
  • gnupg
  • isc-dhcp
  • lighttpd
  • mariadb/mysql
  • nfs-utils
  • nginx
  • nodejs
  • openldap
  • openssh
  • postfix
  • proftpd
  • pure-ftpd
  • rsyslog
  • samba
  • sendmail
  • sysklogd
  • syslog-ng
  • tcp_wrappers
  • vsftpd
  • xinetd
  • WordPress

That said, the  size of the buffer being overwritten is very limited; at only four to eight bytes. This makes it very challenging to actually exploit this flaw in many cases. So while quite a few packages may use the vulnerable function, not all of them actually pose a real-world risk.

It turns out that this particular glibc flaw was discovered and patched over two years ago. If you have glibc 2.18 or higher, you’re not affected. However, at the time it was patched the flaw was considered a bug rather than a security vulnerability, so many Linux distributions didn’t port the glibc update to their distro.

A quick way to check the glibc version on your Linux systems is to type the following command:

ldd --version

If that reports a version lower than 2.18, you need to upgrade. If you’re interested, this blog post has a lot more good information about testing for the flaw. The good news is every major Linux distribution has since updated. If you run Linux systems (especially public servers), I recommend you get your distro’s latest updates to fix this vulnerability.

Also, keep in mind that many hardware devices (often known as the Internet of Things) are actually embedded linux systems, which may need updates as well. Not to mention, some administrators may run Linux software ports on Windows and OS X systems as well. In these cases, it’s possible you might have vulnerable versions of glibc on those non-Linux systems.

Does GHOST Affect WatchGuard Products?

You may know that many WatchGuard product are Linux-based systems, and wonder how this flaw affects them. For the most part, this flaw has little to no impact to most of our products, with a few exceptions. Here are the details:

  • WatchGuard XCS appliances – Not Affected.
  • WatchGuard Wireless Access Points – Not Affected.
  • Dimension v1.3 and higher – Not Affected.
  • Dimension v1.2 and lower – Affected, but Dimension should have already auto-updated. The version of Ubuntu shipping with Dimension v1.2 does use a vulnerable glibc package. However, Dimension auto-updates, and downloads Ubuntu’s latest patches. Since Ubuntu released a patch long ago, your Dimension server should already be patched (as long as you didn’t disable auto-updates).
  • WatchGuard XTM appliances – Affected, but not likely exploitable. XTM Fireware does contain the vulnerable version of glibc. HOWEVER, you are only vulnerable to this issue if a Linux service uses the gethostbyname() funtion. For better security, and IPv6 interoperability, our engineers use the newer getaddrinfo() to resolve hostnames, which is not affected by this vulnerability. We have not found any packages using the vulnerable function, so we believe this flaw has little to no real-world impact on our XTM devices. That said, we have already patched our glibc library, and XTM owners will receive this update in the next scheduled Fireware release. If you’d like to know more about the difference between these functions, I recommend you read this post.
  • WatchGuard SSL VPN appliances – AffectedOur SSL VPN appliance does use the vulnerable library, and is affected by this flaw. We have already patched the flaw internally, and are currently scheduling a release vehicle for the update. I’ll update this post when we know a solid date.

So to summarize. If you use Linux systems, be sure to patch them as soon as you can. Most WatchGuard products aren’t really impacted by this flaw, but we recommend you install firmware updates when we release them. If you want to know more about this interesting and wide-spread issue, I’ve included a few references below. — Corey Nachreiner, CISSP (@SecAdept)

GHOST Vulnerability References:

How to Neuter POODLE (New SSL Vulnerability)

Surprise, surprise… Researcher’s have found yet another OpenSSL vulnerability. They’ve named this one POODLE. Silly name, I know, but at least it stands for something—Padding Oracle On Downgraded Legacy Encryption.

Attack POODLE

In short, POODLE is a protocol level cryptography flaw in Secure Sockets Layer version 3 (SSLv3), which is one of the many encryption protocols available to SSL/TLS implementations like OpenSSL, used to encrypt network traffic. While SSL can encrypt any traffic, it’s most commonly associated with secure web communications (HTTPS). SSLv3 is one of the older encryption protocols in OpenSSL’s library, having been around for 18 years or so. Newer protocols like TLS 1.0-1.2 are much more secure, but we’ve kept SSLv3 around for legacy interoperability reasons. Since this new vulnerability allows attackers to decrypt SSLv3 traffic, it’s time we get rid of SSLv3 for good.

The POODLE flaw is fairly complex, and hard to understand without a deeper comprehension of cryptography. If you’d really like to dive into the details, I recommend you read the paper [PDF] by the Google researchers who found the flaw, or check out this detailed explanation. However, here are the basics:

  1. First, this vulnerability requires a Man-in-the-Middle (MitM) attack to succeed. An attacker can only perform it if he can intercept traffic between you and the SSL server. Performing MitM attacks can range from extremely difficult to trivial, depending on the circumstances. For instance, if you join an unsecured WiFi network, attackers on the same network can quite easily intercept your traffic, whereas intercepting Internet traffic is exceptionally more difficult, and typically requires ISP level interception (or at least DNS poisoning) to pull off.
  2. Next, this attack only works against SSLv3 encrypted traffic, so the attacker needs to somehow force you to use it. This is a much easier hurdle for attackers to overcome. The SSL/TLS protocol includes a “downgrade” feature that allows SSL clients and servers to negotiate which encryption protocol they agree on, depending on what they both support. With a MitM attack, the attacker can intercept and manipulated the negotiations to ensure your browser and the server settle on SSLv3 encryption.
  3. At this point, an attacker can take advantage of the SSLv3 flaw (which is essentially a vulnerability in how SSLv3’s CBC cipher suites use padding) to decrypt certain bytes of your secured traffic. Again, see the paper if you are interested in the technical and mathematical detail. However, there are some caveats here. Basically, the educated guesses used in this attack will only work 1 in 256 times.  So this attack requires the same data be sent over newly created SSLv3 connection hundreds of times. Forcing hundreds of requests is easy when targeting web browsers, since the MitM attack allows the attacker to inject malicious javascript into your web session. This javascript allows the attacker to silently force your browser to do what he needs. However, there are many other clients that use SSL/TLS to encrypt communications, including VPN clients, and apps on your mobile device. Since this attack relies on malicious javascript, attackers can’t easily exploit it against non-browser SSL clients. In any case, once this attack succeeds in decrypting one byte, it’s trivial for the attacker to decrypt the rest of your secure message.
  4.  So what can attackers do by decrypting SSL encrypted web sessions? Most likely, they’d leverage this flaw to try to intercept your encrypted HTTP session cookie. This essentially allows them to hijack your secure web sessions, and do anything you could do on the particular secure site you’re visiting. They wouldn’t obtain your passwords, but they’d have access to your secure web account.

While this sounds pretty bad, and it can be when the attack succeeds, the mitigating factors mentioned above really lessen the severity of this flaw. MitM attacks are not trivial to pull off in most cases, and this exploit’s javascript requirement means it can only easily target web browsers, not other SSL-based clients. Furthermore, if either end (client or server) disables SSLv3, the attack is dead in the water. In fact, NIST only assigns this vulnerability (CVE-2014-3566) a CVSS severity rating of 4.3, which is on the lower medium range of their severity scale. Though many of the media outlet reporting on this flaw have made it sound extremely dangerous, I would only give it a medium severity. It’s definitely something you want to mitigate, but it is not nearly as dangerous as the Heartbleed and Shellshock flaws the media has compared it to.

How to Protect Yourself from POODLE:

Simply put, disable SSLv3!

SSLv3 is an antiquated and broken encryption protocol. Every modern browser and SSL client supports much more recent encryption options. Disabling SSLv3 is the only way to completely protect yourself.

That said, some organizations may still use some legacy web applications, especially ones that require Internet Explorer (IE) 6 running on XP, which depend on SSLv3. Frankly, it’s time you get rid of those applications. In order to quantify today’s minimal SSLv3 usage, CloudFlare monitored all their customers’ traffic and found only 0.09% of it was SSLv3. When monitoring only secure web (HTTPS) traffic, SSLv3 usage jumped to 0.65%, but that’s still a tiny fraction of web traffic. We recommend you help bring this number to zero by getting rid of SSLv3 in your organization

So how do you disable SSLv3? There are two sides to the equation—the server and the client. You only have to disable one side for the attack to fail.

Since this attack targets clients, and seems to primarily affect web browsers, I recommend you disable SSLv3 in your browsers first. All popular web browsers have configuration settings that allow you to do so. The folks at Zmap.io have kindly provided an instruction page detailing how to disable SSLv3 in the popular browsers; check it out. Furthermore, most browser vendors have promised to disable SSLv3 by default in their next software release. Once you have disabled SSLv3 in your browser, attackers cannot leverage this flaw to decrypt your traffic, even if you connect to a web server that still has SSLv3 enabled.

That said, you also should disable SSLv3 on any servers you run, just to help protect the rest of the world against this flaw. The creators of OpenSSL have released an update that fixes this vulnerability (and three others). Besides allowing you to disable SSLv3 on your server, the latest version of OpenSSL supports a feature called TLS_FALLBACK_SCSC, which essentially prevents MitM attackers from forcing clients to downgrade to a certain encryption protocol. Many other Linux distributions and SSL implementations have also released updates. Go get them.

As an aside, once you’ve disabled SSLv3 in your browsers and servers, you can check the results using the following sites:

Are WatchGuard Products Affected by POODLE?

In short, yes.

WatchGuard appliances use OpenSSL and are affected by this vulnerability to varying degrees. The impacted products include:

  • XTM appliances – WatchGuard’s web-based user interfaces (UI), whether the administrative interface or the VPN client portal, do support SSLv3, and are vulnerable to this. However, you can mitigate this flaw by limiting exposure to the Web UI. There is no reason to allow Internet users to access that administrative interface. Also, our SSL VPN clients do NOT support SSLv3. So mobile VPN connections are not affected. We are making updates to our XTM firmware to disable SSLv3 by default.
  • XCS appliances – The XCS’s Web UI does support SSLv3 by default. However, you can disable it for the Web UI, and should do so. Our mail engine does also support SSLv3, and you can’t currently disabled it in the mail engine. That said, this exploit primarily targets web browsers, so the exposure in the mail engine should be low. In any case, we are making changes to the XCS firmware to disable SSLv3.
  • SSL VPN appliances – The SSL VPN appliances administrative Web UI uses SSLv3, and your currently can’t disable it. However, you can limit exposure simply by not allowing external access to the Web UI. As far as client VPN connections, you can disable SSLv3 in the Manage System => Device Setting page. Doing so ensures attackers can’t exploit this flaw to intercept and decrypt mobile SSL VPN traffic. We will release and update to disable SSLv3 in the Web UI.

This vulnerability’s impact to our appliances is relatively low. Nonetheless, WatchGuard will release updated versions for all affected software and devices that are under support. We are currently planning all these releases, and we will update this post as the dates and releases become available. In any case, if you limit access to the web-based administration interfaces on your WatchGuard appliances, the vulnerability poses you little risk. Furthermore, if you disable SSLv3 in your browser, attackers can’t even leverage it against you, whether or not the appliance uses SSLv3.

To summarize, POODLE is a big enough issue that you should definitely disable SSLv3 in all your browsers and servers as soon as you can. However, despite the wide and alarming coverage of this issue, it does not pose a huge, real-world risk to most users. If you update your browsers, and avoid unsecured WiFi connections, POODLE will likely not bite, and is easy to neuter. — Corey Nachreiner, CISSP (@SecAdept)

 

How to Neuter POODLE (New SSL Vulnerability)

Surprise, surprise… Researcher’s have found yet another OpenSSL vulnerability. They’ve named this one POODLE. Silly name, I know, but at least it stands for something—Padding Oracle On Downgraded Legacy Encryption.

Attack POODLE

In short, POODLE is a protocol level cryptography flaw in Secure Sockets Layer version 3 (SSLv3), which is one of the many encryption protocols available to SSL/TLS implementations like OpenSSL, used to encrypt network traffic. While SSL can encrypt any traffic, it’s most commonly associated with secure web communications (HTTPS). SSLv3 is one of the older encryption protocols in OpenSSL’s library, having been around for 18 years or so. Newer protocols like TLS 1.0-1.2 are much more secure, but we’ve kept SSLv3 around for legacy interoperability reasons. Since this new vulnerability allows attackers to decrypt SSLv3 traffic, it’s time we get rid of SSLv3 for good.

The POODLE flaw is fairly complex, and hard to understand without a deeper comprehension of cryptography. If you’d really like to dive into the details, I recommend you read the paper [PDF] by the Google researchers who found the flaw, or check out this detailed explanation. However, here are the basics:

  1. First, this vulnerability requires a Man-in-the-Middle (MitM) attack to succeed. An attacker can only perform it if he can intercept traffic between you and the SSL server. Performing MitM attacks can range from extremely difficult to trivial, depending on the circumstances. For instance, if you join an unsecured WiFi network, attackers on the same network can quite easily intercept your traffic, whereas intercepting Internet traffic is exceptionally more difficult, and typically requires ISP level interception (or at least DNS poisoning) to pull off.
  2. Next, this attack only works against SSLv3 encrypted traffic, so the attacker needs to somehow force you to use it. This is a much easier hurdle for attackers to overcome. The SSL/TLS protocol includes a “downgrade” feature that allows SSL clients and servers to negotiate which encryption protocol they agree on, depending on what they both support. With a MitM attack, the attacker can intercept and manipulated the negotiations to ensure your browser and the server settle on SSLv3 encryption.
  3. At this point, an attacker can take advantage of the SSLv3 flaw (which is essentially a vulnerability in how SSLv3’s CBC cipher suites use padding) to decrypt certain bytes of your secured traffic. Again, see the paper if you are interested in the technical and mathematical detail. However, there are some caveats here. Basically, the educated guesses used in this attack will only work 1 in 256 times.  So this attack requires the same data be sent over newly created SSLv3 connection hundreds of times. Forcing hundreds of requests is easy when targeting web browsers, since the MitM attack allows the attacker to inject malicious javascript into your web session. This javascript allows the attacker to silently force your browser to do what he needs. However, there are many other clients that use SSL/TLS to encrypt communications, including VPN clients, and apps on your mobile device. Since this attack relies on malicious javascript, attackers can’t easily exploit it against non-browser SSL clients. In any case, once this attack succeeds in decrypting one byte, it’s trivial for the attacker to decrypt the rest of your secure message.
  4.  So what can attackers do by decrypting SSL encrypted web sessions? Most likely, they’d leverage this flaw to try to intercept your encrypted HTTP session cookie. This essentially allows them to hijack your secure web sessions, and do anything you could do on the particular secure site you’re visiting. They wouldn’t obtain your passwords, but they’d have access to your secure web account.

While this sounds pretty bad, and it can be when the attack succeeds, the mitigating factors mentioned above really lessen the severity of this flaw. MitM attacks are not trivial to pull off in most cases, and this exploit’s javascript requirement means it can only easily target web browsers, not other SSL-based clients. Furthermore, if either end (client or server) disables SSLv3, the attack is dead in the water. In fact, NIST only assigns this vulnerability (CVE-2014-3566) a CVSS severity rating of 4.3, which is on the lower medium range of their severity scale. Though many of the media outlet reporting on this flaw have made it sound extremely dangerous, I would only give it a medium severity. It’s definitely something you want to mitigate, but it is not nearly as dangerous as the Heartbleed and Shellshock flaws the media has compared it to.

How to Protect Yourself from POODLE:

Simply put, disable SSLv3!

SSLv3 is an antiquated and broken encryption protocol. Every modern browser and SSL client supports much more recent encryption options. Disabling SSLv3 is the only way to completely protect yourself.

That said, some organizations may still use some legacy web applications, especially ones that require Internet Explorer (IE) 6 running on XP, which depend on SSLv3. Frankly, it’s time you get rid of those applications. In order to quantify today’s minimal SSLv3 usage, CloudFlare monitored all their customers’ traffic and found only 0.09% of it was SSLv3. When monitoring only secure web (HTTPS) traffic, SSLv3 usage jumped to 0.65%, but that’s still a tiny fraction of web traffic. We recommend you help bring this number to zero by getting rid of SSLv3 in your organization

So how do you disable SSLv3? There are two sides to the equation—the server and the client. You only have to disable one side for the attack to fail.

Since this attack targets clients, and seems to primarily affect web browsers, I recommend you disable SSLv3 in your browsers first. All popular web browsers have configuration settings that allow you to do so. The folks at Zmap.io have kindly provided an instruction page detailing how to disable SSLv3 in the popular browsers; check it out. Furthermore, most browser vendors have promised to disable SSLv3 by default in their next software release. Once you have disabled SSLv3 in your browser, attackers cannot leverage this flaw to decrypt your traffic, even if you connect to a web server that still has SSLv3 enabled.

That said, you also should disable SSLv3 on any servers you run, just to help protect the rest of the world against this flaw. The creators of OpenSSL have released an update that fixes this vulnerability (and three others). Besides allowing you to disable SSLv3 on your server, the latest version of OpenSSL supports a feature called TLS_FALLBACK_SCSC, which essentially prevents MitM attackers from forcing clients to downgrade to a certain encryption protocol. Many other Linux distributions and SSL implementations have also released updates. Go get them.

As an aside, once you’ve disabled SSLv3 in your browsers and servers, you can check the results using the following sites:

Are WatchGuard Products Affected by POODLE?

In short, yes.

WatchGuard appliances use OpenSSL and are affected by this vulnerability to varying degrees. The impacted products include:

  • XTM appliances – WatchGuard’s web-based user interfaces (UI), whether the administrative interface or the VPN client portal, do support SSLv3, and are vulnerable to this. However, you can mitigate this flaw by limiting exposure to the Web UI. There is no reason to allow Internet users to access that administrative interface. Also, our SSL VPN clients do NOT support SSLv3. So mobile VPN connections are not affected. We are making updates to our XTM firmware to disable SSLv3 by default.
  • XCS appliances – The XCS’s Web UI does support SSLv3 by default. However, you can disable it for the Web UI, and should do so. Our mail engine does also support SSLv3, and you can’t currently disabled it in the mail engine. That said, this exploit primarily targets web browsers, so the exposure in the mail engine should be low. In any case, we are making changes to the XCS firmware to disable SSLv3.
  • SSL VPN appliances – The SSL VPN appliances administrative Web UI uses SSLv3, and your currently can’t disable it. However, you can limit exposure simply by not allowing external access to the Web UI. As far as client VPN connections, you can disable SSLv3 in the Manage System => Device Setting page. Doing so ensures attackers can’t exploit this flaw to intercept and decrypt mobile SSL VPN traffic. We will release and update to disable SSLv3 in the Web UI.

This vulnerability’s impact to our appliances is relatively low. Nonetheless, WatchGuard will release updated versions for all affected software and devices that are under support. We are currently planning all these releases, and we will update this post as the dates and releases become available. In any case, if you limit access to the web-based administration interfaces on your WatchGuard appliances, the vulnerability poses you little risk. Furthermore, if you disable SSLv3 in your browser, attackers can’t even leverage it against you, whether or not the appliance uses SSLv3.

To summarize, POODLE is a big enough issue that you should definitely disable SSLv3 in all your browsers and servers as soon as you can. However, despite the wide and alarming coverage of this issue, it does not pose a huge, real-world risk to most users. If you update your browsers, and avoid unsecured WiFi connections, POODLE will likely not bite, and is easy to neuter. — Corey Nachreiner, CISSP (@SecAdept)

 

OpenSSL Patches Six Vulnerabilities, Including a MitM Flaw

OpenSSL CCS InjectionToday, the OpenSSL team released a critical update for their popular SSL/TLS package, which fixes six security vulnerabilities in their product, including a relatively serious Man-in-the-Middle (MitM) flaw. If you use OpenSSL, you should read up on these issues and update OpenSSL immediately. WatchGuard products, like many others that use OpenSSL, are affected by these issues to different extents. Our engineers are diligently working to release patches for these flaws as soon as possible.

OpenSSL is a very popular implementation of the SSL/TLS cryptography protocols, used to encrypt many network communications, including secure web communications. This week, the OpenSSL team released an update that fixes six vulnerabilities, including some publicly reported ones. Combined, the flaws affect all current versions of OpenSSL to some extent.

The flaws differ technically, and in scope and impact. For instance, one is a buffer overflow flaw that could allow attackers to execute code, assuming you use a particular OpenSSL feature (DTLS), while another allows attackers to crash OpenSSL, resulting in a Denial of Service (DoS) situation. However, the flaw recieving the most attention is a MitM vulnerability involving OpenSSL’s ChangeCipherSpec functionality. In short, if an attacker can get between a client and server, both of which have vulnerable versions of OpenSSL, he can exploit this flaw to decrypt SSL communications.

While this sounds fairly serious, there are a number of mitigating factor that lessen the severity of the MitM flaw. While all versions of the OpenSSL client are vulnerable to this issue, only two server versions are vulnerable. Also, very few client programs or devices use OpenSSL to make client connections. For instance, the popular browsers aren’t vulnerable to this issue. Finally, the attacker needs to intercept traffic between the client and server for this attack to succeed. Based on these factors, Android devices running on wireless networks pose the most risk, since Android is one of the platforms that uses the OpenSSL client, and wireless networks make it easier to intercept other’s traffic.

In the end, these flaws are not as severe as the previous Heartbleed vulnerability (attackers could exploit that from anywhere, without intercepting traffic). Nonetheless, we highly recommend OpenSSL administrators install the patch immediately, and start looking for updates from other vendors who use OpenSSL in their own products.

WatchGuard Products – (Updated on Jun-17)

Finally, WatchGuard appliances are affected by some of these vulnerabilities (to varying degrees). Although they do not have the same level of impact as Heartbleed, a broader range of OpenSSL versions are vulnerable. WatchGuard products impacted are:

  • Fireware XTM version 11.3 to 11.9 and associated WSM management software
  • SSL VPN clients for XTM
  • XCS
  • SSL VPN appliance

The level of risk is relatively low, but WatchGuard will release updated versions for all affected software for devices that are under support. Unlike Heartbleed, certificates do NOT need to be updated. Our IPS signature team has also released signatures to address one of the vulnerabilities (CVE-2014-3466) in signature set 4.422. Estimated release dates and version numbers for patched firmware, including SSL VPN clients, are:

  • XCS Hotfix – June 10th for version 10, June 11th for version 9. Posted!
  • 11.3.8 – June 12th (for e-Series devices) – Posted
  • 11.6.8 – June 13th (for XTM 21/22/23 devices) – Posted
  • 11.7.5 – June 12th – Posted
  • 11.8.4 – June 23rd – Posted
  • 11.9.1 – June 24th – Posted

These dates are subject to change depending on outcome of Quality Assurance process. WatchGuard will continue to provide latest information about these vulnerabilities and latest status on release dates in this blog post.

— Corey Nachreiner, CISSP (@SecAdept),  Brendan Patterson, CISSP

 

UPDATE TO: Advanced Attackers Exploit IE 0day in the Wild

Severity: High

Summary:

  • This vulnerability affects: All versions of Internet Explorer (IE)
  • How an attacker exploits it: By enticing a user to visit web site containing malicious content
  • Impact: An attacker can execute code with your privileges, potentially gaining complete control of your computer
  • What to do: Install Microsoft’s emergency IE patch immediately, or let Windows Update do it for you

Exposure:

On Monday, we released an alert warning about a zero day vulnerability affecting all version of Internet Explorer. Researchers discovered attackers exploiting this critical flaw in the wild, and Microsoft had not yet released a patch at that time.

Today, Microsoft released an out-of-cycle security bulletin containing an update to fix this serious vulnerability. As mentioned in our original alert, IE suffers from something called a “use after free” memory corruption vulnerability. By enticing one of your users to a web site containing malicious content, an attacker can exploit this flaw to execute code on your machine, with your privileges. As usual, if you have local administrator privileges, the attacker gains full control of your machine.

Keep in mind, today’s attackers often hijack legitimate web pages and booby-trap them with malicious code. Typically, they do this via hosted web ads or through SQL injection and cross-site scripting (XSS) attacks. Even recognizable and authentic websites could pose a risk to your users if hijacked in this way, and the vulnerabilities described in today’s bulletin are perfect for use in drive-by download attacks. Furthermore, attackers are already exploiting this particular flaw in targeted attacks. We highly recommend you install Microsoft’s IE update immediately

We have included the original alert below for your convenience.

Solution Path:

Microsoft has released IE updates to correct this vulnerability. You should download, test, and deploy the updates immediately, or let Windows Update do it for you. You can find the updates in the “Affected and Non-Affected Software” section of Microsoft’s IE bulletin. Also note, Microsoft has included updates for Windows XP customers, despite their End-of-Life date last month.

If for some reason you cannot patch immediately, there are also some workarounds than can mitigate the issue. We detail those workarounds in our original alert, which we’ve included below for your convenience.

For All WatchGuard Users:

As mentioned in our original alert, there are a number of things WatchGuard XTM customers can do to protect themselves. For instance, you can use our proxy policies to block Flash content by extension (.SWF) or by MIME type (application/x-shockwave-flash). Furthermore, our IPS service includes signatures that block this IE exploit (update to signature set 4.410). Nonetheless, we still highly recommend you install Microsoft’s IE update to completely protect yourself from this attack.

Status:

Microsoft has released patches to fix this vulnerability.

References:

This alert was researched and written by Corey Nachreiner, CISSP (@SecAdept).


Over the weekend, Microsoft released a critical security advisory warning customers of a serious new zero day vulnerability in Internet Explorer (IE), which attackers are exploiting in the wild. Around the same time, Kaspersky also noted an attack campaign leveraging a new Adobe Flash zero day flaw, which Adobe patched today. I’ll discuss both issues below, starting with the IE issue.

IE Zero Day in the Wild

According to this blog post, researchers at FireEye discovered advanced attackers exploiting this zero day IE flaw as part of a persistent attack campaign they are calling “Operation Clandestine Fox.” The attack targets IE 9-11 and also leverages a Flash flaw to help bypass some of Windows’ security features.

Shortly after FireEye’s post, Microsoft released a security advisory confirming the previously undiscovered flaw in IE. The advisory warns that the flaw affects all versions of IE (though the attack seems to target IE 9-11). While Microsoft is still researching the issue, the vulnerability seems to be a “use after free” class of memory corruption vulnerability. In short, if an attacker can entice you to a web page containing maliciously crafted content, he could exploit this flaw to execute code on your machine, with your privileges. As usual, if you have local administrator privileges, the attacker would gain full control of your machine. It’s interesting to note, the attackers also leverage a known Adobe Flash issue to help defeat some of Microsoft’s Windows memory protection features.

Zero day IE vulnerabilities are relatively rare, and very dangerous. Attackers are already exploiting this IE one in the wild, so it poses a significant risk. Unfortunately, Microsoft just learned of the flaw, so they haven’t had time to patch it yet. I suspect Microsoft will release an out-of-cycle patch for this flaw very shortly since this is a high-profile issue. In the meantime here a few workarounds to help mitigate the flaw:

  • Temporarily use a different web browser – I’m typically not one to recommend one web browser over another, as far as security is concerned. They all have had vulnerabilities. However, this is a fairly serious issue.  So you may want to consider temporarily using a different browser until Microsoft patches.
  • Install Microsoft EMETEMET is an optional Microsoft tool that adds additional memory protections to Windows. I described EMET in a previous episode of WatchGuard Security Week in Review. Installing EMET could help protect your computer from many types of memory corruption flaws, including this one. This Microsoft blog post shares more details on how it can help with this issue.
  • Configure Enhanced Security Configuration mode on Windows Servers – Windows Servers in Enhanced Security Configuration mode are not vulnerable to many browser-based attacks.
  • Disable VML in IE – This exploit seems to rely on VML to work. Microsoft released a blog post detailing how disabling VML in IE, or running IE in “Enhanced Protection Mode” can help.
  • Make sure your AV and IPS is up to date – While not all IPS and AV systems have signatures for all these attacks yet, they will in the coming days. In fact, WatchGuard’s IPS engineers have already created signatures to catch this attack. We are QA testing the signatures now, but they should be available to XTM devices shortly. Whatever IPS system you use, be sure to keep your AV and IPS systems updating regularly, to get the latest protections.
  • WatchGuard XTM customers can block Flash with proxies – If you own a WatchGuard XTM security appliance, you can use our proxy policies to block certain content, including Flash content. For instance, you can use our SMTP or HTTP proxies to block SWF files by extensions (.SWF) or by MIME type (application/x-shockwave-flash). Keep in mind, blocking Flash blocks both legitimate and malicious content. So only implement this workaround if you are ok with your users not accessing normal Flash pages.

Adobe Patches Flash Zero Day

Coincidentally, Adobe also released an emergency Flash update today fixing a zero day exploit that other advanced attackers are also exploiting in a targeted watering hole campaign. The patch fixes a single vulnerability in the popular Flash media player, which attackers could exploit to run arbitrary code on your system; simply by enticing you to a web site containing specially crafted Flash content. This exploit was discovered in the wild by Kaspersky researchers (one of our security partners). According to Kaspersky’s research, the exploit was discovered on a Syrian website, and seems to be designed to target potential Syrian dissidents.

The good news is there is a patch for this flaw. So if you use Adobe Flash, go get the latest update now. By the way, some browsers like Chrome and IE 11 embed Flash directly, so you will also have to update those browsers individually. Finally, though the IE zero day I mentioned earlier does rely on a Flash issue, this particular zero day Flash flaw is totally unrelated. One additional note; WatchGuard’s IPS engineers have also created a signature for this exploit as well. It will be available shortly, once testing is complete.

So to summarize, if you use IE, disable VML, install EMET, and watch for an upcoming patch. If you use Flash, updates as soon as you can. I will be sure to inform you here, as soon as Microsoft releases their real patch or FixIt. — Corey Nachreiner, CISSP (@SecAdept)

Advanced Attackers Exploit IE & Flash 0days in the Wild

Over the weekend, Microsoft released a critical security advisory warning customers of a serious new zero day vulnerability in Internet Explorer (IE), which attackers are exploiting in the wild. Around the same time, Kaspersky also noted an attack campaign leveraging a new Adobe Flash zero day flaw, which Adobe patched today. I’ll discuss both issues below, starting with the IE issue.

IE Zero Day in the Wild

According to this blog post, researchers at FireEye discovered advanced attackers exploiting this zero day IE flaw as part of a persistent attack campaign they are calling “Operation Clandestine Fox.” The attack targets IE 9-11 and also leverages a Flash flaw to help bypass some of Windows’ security features.

Shortly after FireEye’s post, Microsoft released a security advisory confirming the previously undiscovered flaw in IE. The advisory warns that the flaw affects all versions of IE (though the attack seems to target IE 9-11). While Microsoft is still researching the issue, the vulnerability seems to be a “use after free” class of memory corruption vulnerability. In short, if an attacker can entice you to a web page containing maliciously crafted content, he could exploit this flaw to execute code on your machine, with your privileges. As usual, if you have local administrator privileges, the attacker would gain full control of your machine. It’s interesting to note, the attackers also leverage a known Adobe Flash issue to help defeat some of Microsoft’s Windows memory protection features.

Zero day IE vulnerabilities are relatively rare, and very dangerous. Attackers are already exploiting this IE one in the wild, so it poses a significant risk. Unfortunately, Microsoft just learned of the flaw, so they haven’t had time to patch it yet. I suspect Microsoft will release an out-of-cycle patch for this flaw very shortly since this is a high-profile issue. In the meantime here a few workarounds to help mitigate the flaw:

  • Temporarily use a different web browser – I’m typically not one to recommend one web browser over another, as far as security is concerned. They all have had vulnerabilities. However, this is a fairly serious issue.  So you may want to consider temporarily using a different browser until Microsoft patches.
  • Install Microsoft EMETEMET is an optional Microsoft tool that adds additional memory protections to Windows. I described EMET in a previous episode of WatchGuard Security Week in Review. Installing EMET could help protect your computer from many types of memory corruption flaws, including this one. This Microsoft blog post shares more details on how it can help with this issue.
  • Configure Enhanced Security Configuration mode on Windows Servers – Windows Servers in Enhanced Security Configuration mode are not vulnerable to many browser-based attacks.
  • Disable VML in IE – This exploit seems to rely on VML to work. Microsoft released a blog post detailing how disabling VML in IE, or running IE in “Enhanced Protection Mode” can help.
  • Make sure your AV and IPS is up to date – While not all IPS and AV systems have signatures for all these attacks yet, they will in the coming days. In fact, WatchGuard’s IPS engineers have already created signatures to catch this attack. We are QA testing the signatures now, but they should be available to XTM devices shortly. Whatever IPS system you use, be sure to keep your AV and IPS systems updating regularly, to get the latest protections.
  • WatchGuard XTM customers can block Flash with proxies – If you own a WatchGuard XTM security appliance, you can use our proxy policies to block certain content, including Flash content. For instance, you can use our SMTP or HTTP proxies to block SWF files by extensions (.SWF) or by MIME type (application/x-shockwave-flash). Keep in mind, blocking Flash blocks both legitimate and malicious content. So only implement this workaround if you are ok with your users not accessing normal Flash pages.

Adobe Patches Flash Zero Day

Coincidentally, Adobe also released an emergency Flash update today fixing a zero day exploit that other advanced attackers are also exploiting in a targeted watering hole campaign. The patch fixes a single vulnerability in the popular Flash media player, which attackers could exploit to run arbitrary code on your system; simply by enticing you to a web site containing specially crafted Flash content. This exploit was discovered in the wild by Kaspersky researchers (one of our security partners). According to Kaspersky’s research, the exploit was discovered on a Syrian website, and seems to be designed to target potential Syrian dissidents.

The good news is there is a patch for this flaw. So if you use Adobe Flash, go get the latest update now. By the way, some browsers like Chrome and IE 11 embed Flash directly, so you will also have to update those browsers individually. Finally, though the IE zero day I mentioned earlier does rely on a Flash issue, this particular zero day Flash flaw is totally unrelated. One additional note; WatchGuard’s IPS engineers have also created a signature for this exploit as well. It will be available shortly, once testing is complete.

So to summarize, if you use IE, disable VML, install EMET, and watch for an upcoming patch. If you use Flash, updates as soon as you can. I will be sure to inform you here, as soon as Microsoft releases their real patch or FixIt. — Corey Nachreiner, CISSP (@SecAdept)

The Heartbleed OpenSSL Vulnerability; Patch OpenSSL ASAP

On Monday, the OpenSSL team released a critical update for their popular SSL/TLS package, which fixes a serious cryptographic weakness in their product. If you use OpenSSL, you should read up on this issue and update OpenSSL immediately. WatchGuard products, like many others that use OpenSSL, are affected by this issue. We are currently working on updates to fix the flaw.

OpenSSL is a very popular implementation of the SSL/TLS cryptography protocols, used to encrypt many network communications, including secure web communications. This week, a Google security researcher disclosed a serious vulnerability (CVE-2014-0160) that affects OpenSSL 1.0.1 – 1.0.1f (and 1.0.2-beta), which is colloquially being called “The Heartbleed Bug.” The issue does not affect OpenSSL 0.9.8 and below.

The flaw has to do with the TLS heartbeat extension. Without going into all the technical details, a remote attacker could exploit this flaw to repeatedly reveal 64K of memory contents from a SSL/TLS connected client or server. 64K of memory might seem small, but an attacker could repeatedly exploit this flaw to gather enough contents from memory to compromise SSL key material, certificates, usernames, passwords, and potentially gain access to your entire decrypted communications. For complete details on the flaw, including a FAQ answering the most common question, I recommend you check out the Heartbleed web page.

This is a very serious vulnerability to a package than many products rely on to secure web communications. If you use the 1.0.1 branch of OpenSSL yourself, you need to update to 1.0.1g. Furthermore, this flaw will likely affect many other products you might use. Be sure to look out for alerts from your vendors on this issue.

Finally, WatchGuard XTM and XCS appliances are affected by this vulnerability (to varying degrees). Our engineering team is currently working on a fix for the issue. We should be releasing an XTM 11.8.3 CSP update shortly, which will fix the issue for XTM appliances. By the way, the flaw only affect 11.8.x versions of XTM. If you are using XTM 11.7.x or below, it uses an older version of OpenSSL which is not affected by this issue. Also, the XCS appliances are only affected if you use SecureMail. Finally, WatchGuard’s SSL VPN appliances are NOT affected by the issue since they use older versions of OpenSSL.

Please keep an eye on this blog for more details as we will post the update as soon as it’s available and tested. — Corey Nachreiner, CISSP (@SecAdept

 

Out-of-Cycle Word FixIt Corrects Zero Day Vulnerability

If you’re worried about spear phishing attacks (and if you’re not, you should be), grab Microsoft’s emergency FixIt to mitigate a zero day vulnerability attackers are exploiting in the wild.

In a security advisory released yesterday, Microsoft warned of a zero day vulnerability in Word, which attackers are exploiting in what Microsoft describes as limited, targeted attacks. Apparently, the exploit in the wild targets Word 2010, but the flaw affects other versions of Word as well. Since this is an early advisory, it doesn’t describe the flaw in much technical detail. However, it does mention attackers can trigger the flaw with specially crafted rich text format (RTF) files. If an attacker can entice you to view a malicious RTF in Word, he could exploit this vulnerability to execute code on you computer, with your privileges. If you are an administrator, the attacker gains complete control of your PC.

By default, most current version of Office use Word as Outlook’s email viewer. This mean attackers can trigger this flaw just by getting you to open an RTF attached to an email. According to some on Twitter, simply previewing an email with a malicious RTF triggers the flaw.

While Microsoft hasn’t had time to release a full patch yet, they have posted a FixIt that mitigates the risk of this vulnerability. If you use Office, I highly recommend you install the FixIt as soon as you can. Also, Microsoft’s Enhanced Mitigation Experience Toolkit (EMET) can mitigate the risk of any type of memory corruption flaw. In general, I recommend you install EMET on Windows machines to protect them from any zero day, memory-related issues.

I’ll post more details about this flaw during an upcoming Patch Day, when Microsoft releases the final update. In the meantime, if you’d like more information about it you can check out Microsoft’s security blog post— Corey Nachreiner, CISSP (@SecAdept

 

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