DDoS attacks on Dyn caused outages and slowdowns

If you use Twitter, reddit, Amazon, Tumblr, Spotify or Netflix, you may have noticed that they were slower than usual for parts of yesterday. That’s because the affected sites and services use Dyn, a DNS service provider, and Dyn was hit by two huge DDoS attacks yesterday.

The attacks lasted for a few hours, and while they certainly affected a lot of people, they were no more than an inconvenience for most. Still, the surge in the number and size of these attacks is troubling.

Analysis of the attacks shows that they were made possible by the Mirai botnet, which uses a huge network of poorly-secured (and now compromised) DVRs and security cameras. Those are the same tools used in the recent krebsonsecurity.com and OVH DDoS attacks. The source code for Mirai was released to the public recently, which means just about anyone could have caused the Dyn attacks.

Brian Krebs has more.

Update 2016Oct24: Dyn has released a statement about the attack on their systems, in which they clarify the timeline, and confirm that the Mirai botnet was involved. Meanwhile, security expert Bruce Schneier doesn’t believe that the recent attacks were perpetrated by a state actor such as China. He also doesn’t think they were related to the probing attacks he reported earlier. But he is concerned that the attacks will continue to grow in size and frequency, because nobody involved is motivated to fix the problem.

Chinese device maker Hangzhou Xiongmai has issued a recall for several of its webcam models that were used in the attacks.

Serious Linux kernel vulnerability patched

As amusing as it may sound, the recently-patched ‘Dirty Cow’ Linux kernel vulnerability (CVE-2016-5195) highlights a couple of important points:

  • vulnerabilities – even known ones – can remain unpatched in critical software for years; and
  • a misconfigured server that allows uploaded files to be executed is easily hacked.

At first glance, the Dirty Cow vulnerability may not seem particularly noteworthy. It doesn’t directly allow for arbitrary code execution. But it does allow an attacker who already has the ability to run arbitrary code on a target system to gain full access to that system via privilege escalation.

A Linux server that allows user uploads of any kind is normally configured so that uploaded files cannot be executed. However, it’s very easy to get this wrong, especially for web servers. Still, in most cases, being able to run an uploaded file remotely isn’t enough to provide the kind of access attackers want. Dirty Cow provides that access.

Anyone running a Linux server is strongly advised to install the available kernel updates for Dirty Cow immediately.

Silverlight 5.1.50901.0

These days, new Silverlight versions are typically released by Microsoft in connection with monthly Patch Tuesdays. That’s what happened with the latest version, 5.1.50901.0, which should have been installed with the other updates on Windows systems on October 11.

The new version fixes a single vulnerability, as documented in the associated security bulletin (MS16-120) and Knowledge Base article (KB3192884).

You can verify that you’re running the latest version of Silverlight by visiting the Get Microsoft Silverlight page.

Chrome 54.0.2840.59

A new version of Google’s Chrome web browser includes fixes for at least twenty-one security issues.

According to the announcement, Chrome 54 “contains a number of fixes and improvements”, but it doesn’t mention any specifics. If you want to know exactly what’s different, you’ll have to risk crashing your web browser and look at the full change log, which lists at least 10,000 changes.

For most users, Chrome will update itself over the next few days. You can usually trigger an update by running Chrome and navigating to the Help > About page (click the ‘three dots’ icon at the top right).

Adobe software updates: October 2016

Adobe announced new versions of Flash and Reader/Acrobat yesterday.

Flash fixes twelve vulnerabilities in previous versions. The new version also adds some new features, but these are likely only of interest to developers. If you still have Flash enabled in any web browser, you should either update it immediately, or disable Flash in the browser. As usual, Chrome will update itself with the latest version, and Internet Explorer and Edge on Windows will get the new Flash version via Windows Update.

New versions of Reader/Acrobat (XI, DC Classic and DC Continuous) address a whopping seventy-one vulnerabilities in previous versions. If you use a web browser with an Adobe Reader add-on, you should either update it as soon as possible or disable that add-on.

Patch Tuesday: October 2016

It’s the first day of a new era in Windows updates. Windows 7 and 8 now get updates in cumulative rollups, and updates are bundled together.

This month there are ten security bulletins. Each bulletin is associated with one fix for a specific vulnerability in an application, library, or API; or with a bundle of fixes that address several vulnerabilities in Windows.

Each bulletin is associated with at least one Knowledge Base article, and sometimes with additional KB articles that apply to different versions of Windows, Office, .NET, or some other application. Each additional KB article is associated with a version-specific update. There are often two sets of KB articles: one for the security only quality update and one for the security monthly quality update.

All of the security updates this month are available via Microsoft Update. Most are also available from the Microsoft Download Center and the Microsoft Update Catalog (MUC). Downloading updates from the MUC technically requires Internet Explorer, but you can use any other browser by navigating to http://catalog.update.microsoft.com/v7/site/Rss.aspx?q=KBxxxxxxx (replacing KBxxxxxxx with the KB article number).

So far I don’t see anything in these new updates that looks particularly worrisome. Of course there’s always a risk that Microsoft will slip something in that we don’t want, but there’s a non-trivial amount of scrutiny being directed toward Microsoft right now, and I’m confident someone will quickly spot anything untoward.

I was half-expecting the updates to be as poorly documented as Windows 10 updates, but instead the Windows 10 updates are now as well documented as the others. I also thought there would be fewer bundles, and I didn’t expect them to be grouped as sensibly as they are.

The new system is simpler in some ways, and it does at least unify all versions of Windows to some extent, although Windows 10 updates are still treated somewhat differently. It all actually seems less clunky than before, which is a very nice surprise.

Questions remain. It’s unclear how bad updates will be handled. In the past, if an update broke Windows, you could uninstall it. Now, presumably, you’d have to uninstall an entire bundle. Or something. We’ll see how it goes next month when rollups start arriving with multiple months worth of updates.

Update 2016Oct12: Brian Krebs’ take on the new Windows Update system.

Regulating Internet connected (IoT) devices

At this point it’s clear that thousands of poorly-secured IoT devices were used in the recent large-scale DDoS attacks against krebsonsecurity.com and OVH. Ongoing analysis points to devices manufactured by a Chinese company called XiongMai Technologies, which makes generic Digital Video Recorder (DVR) and Internet camera devices that are sold to vendors who use them in their own products.

Chinese vendor Dahua sells products that use these vulnerable devices. Dahua products appear several times in the list of affected devices published by Brian Krebs, and Flashpoint Intel also identifies Dahua devices as being involved.

Companies like XiongMai Technologies and Dahua share the blame for flooding the Internet with these easily-co-opted devices. XiongMai Technologies created devices that are inherently insecure and unsuitable for direct connection to the Internet. Dahua either failed to comprehend the danger, or chose to ignore it, producing deeply flawed consumer devices and – as Brian Krebs puts it – dumping toxic waste onto the Internet. These devices are spread around the globe, most to be plugged in and forgotten for years, ready to be abused by whoever can find them. Some of these devices can’t actually be fixed, since their vulnerabilities exist in firmware that can’t be updated.

Dahua’s response to all this isn’t likely to reduce concerns, since it tries to shift the blame onto users who failed to change default passwords, while ignoring the fact that these passwords cannot be changed in some cases.

What can be done about this? Beyond locating and removing the current crop of vulnerable devices – a difficult task in itself – how can we avoid this situation in the future? Preventing poor quality products from entering the market is ultimately the responsibility of governments. Until authorities get involved, this is likely to keep happening. If they fail to act now, the attacks will continue to get worse until commerce is affected, at which point it will no longer be possible for governments to ignore the problem. Bruce Schneier shares this view.

The good news is that the European Union is already taking action. The EU is planning to upgrade its telecommunications laws, which are now expected to include requirements for labeling IoT devices that are secure and approved for Internet connection. This kind of labeling already works well for showing the energy usage of electrical appliances.

Kudos to the European Commission for recognizing that the ongoing flood of crappy IoT devices is a major contributor to Internet-related problems, including the recent, massive DDoS attacks. Let’s hope that other governing bodies wake up soon.

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