Category Archives: Security

The Cloudflare Incident And Its Impact On

Cloudflare recently announced a security incident that potentially impacts anyone who visited various and sites for the past six months.

What happened?

Cloudflare is a popular service that provides content delivery, DDoS protection and DNS services for web sites.

A software bug Cloudflare’s servers leaked potentially sensitive information. Some of that information ended up in caches all over the Internet. At Google, Microsoft, your ISP, your company’s or university’s proxy servers, and elsewhere. Due to the randomness and distributed nature of the bug, it’s difficult to know what the full impact is. Cloudflare provides the following estimate:

“The greatest period of impact was from February 13 and February 18 with around 1 in every 3,300,000 HTTP requests through Cloudflare potentially resulting in memory leakage (that’s about 0.00003% of requests).”

The bug was introduced on September 22, 2016 and fixed on February 18th, 2017.

The Google Project Zero bug describing the issue in detail can be found at

Cloudflare’s incident report can be found at

The initial Hacker News discussion can be found at

Was Wireshark affected?

The following and sites were behind Cloudflare proxies during the period in question:


Wireshark’s download servers (*, and were not behind Cloudflare.

I browsed to a one of the sites listed above between September 22nd, 2016 and February 18th, 2017. Am I affected?

The chances are slim, but those chances are not zero.

Most of the content that we serve is “static” and “public.” That is, it’s the same for everyone and doesn’t contain any sensitive information. The risk exposed by Cloudflare is from dynamic content that contains sensitive information such as the login page on ask, bugs, wiki, etc. Our web sites get frequent requests for static content, but dynamic requests are relatively infrequent.

In a world where everyone has infinite free time I would have no qualms about recommending that everyone with a account change his or her passwords. However, this is the real world and your time is valuable. If you logged in to one of our sites and used a unique password it might not be worth your time to change it. On the other hand, if your professional reputation depends on your score you probably should. If you have any sort of administrative access you definitely should. Most of our users fall into the first category.

If you’re wondering why it looks like I’m downplaying the importance of changing your passwords, see the next question.

I used a web browser, smart phone, or an internet-connected wearable doohickey between September 22nd, 2016 and February 18th, 2017. Am I affected?

I honestly don’t know. The chances are almost certainly not zero.

Cloudflare is a very popular service. At the time of this writing an unofficial list of affected sites is 69 MB and rising. It includes many of the world’s most popular web sites.

If you’re going to spend time changing passwords, doing so for sites that deal with finance, email, DNA testing, dating, and other parts of your personal life probably ranks higher than that for, say, the Wireshark wiki.

Isn’t a vague answer like “the chances are slim but not zero” a frustratingly craptastic one compared to a definitive “yes” or “no”?

Yes, but it’s also the honest and correct one.

Detecting Heartbleed Traffic

The big news in the tech industry this week is The Heartbleed Bug, a vulnerability that affects a large portion of secure web sites on the Internet. I updated the Wireshark and WinPcap web sites on Monday (along with reissuing and revoking certificates) shortly after OS patches were released.

Our web sites are protected going forward, but what about the past? We have a Shark appliance in our environment but that leads to a challenge. We had about 350 GB of HTTPS on our network on Monday alone. This is just slightly too large to load into Wireshark.

Fortunately one of my coworkers (P.J. Malloy) came up with a BPF filter that matches Heartbleed traffic:

Applying this filter directly on the Shark appliance gave me a much smaller number of packets which I could easily analyze in Wireshark. So far I haven’t found anything suspicious.

Used Cars and Stub Installers

The Wireshark development team works hard to earn the respect of our users. This includes making sure that downloading and installing Wireshark is as easy and trouble-free as possible. Right now the vast majority of our users can go to, follow the big green arrows, and immediately download the appropriate Wireshark package for their platform.

For many years a number of third party sites have also offered Wireshark downloads. Typing “wireshark download” into your favorite search engine will turn up a bunch of them, usually just below links to These sites are popular and often provide valuable services such as reviews and malware prescreening. They also reside outside the Wireshark ecosystem — we don’t link to them and aren’t affiliated with any of them.

"This is the Cadillac of invasive toolbars at a Chevy price!"

Sometimes these sites abuse their relationship with their users. For example a few months ago started using a stub installer which tries to get you to install various toolbars and who-knows-what-else before it installs the package you ultimately want, much like a sleazy car salesman trying to bundle add-ons you don’t want or need.

This sort of bottom-feeding behavior is harmful to our user community and exploits the goodwill we have with our users. Brian Krebs and Gordon “Fyodor” Lyon describe the problem with much more depth and eloquence than I can.

I sent a request to to disable their stub installer for Wireshark. They complied, but there are dozens of other download sites. Trying to keep tabs on all of them would result in a never-ending game of Whac-A-Mole®.

On behalf of the Wireshark development team I promise to provide easily accessible, direct downloads of Wireshark from just as we always have. If you choose to download Wireshark somewhere else we can’t guarantee that the experience will be free of shenanigans so please be careful.

Running Wireshark as You

Running Wireshark on Linux involves an interesting challenge1: Capturing packets requires root access, but Wireshark is big program and we strongly recommend against running it with elevated privileges. On Linux it’s common to see Wireshark running as root, but this is nearly unheard for similarly-sized applications like Firefox and GIMP. How can we avoid running Wireshark as root? Continue reading