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Tag Archives: Web development

Still Not A Fan Of Paywalls

As you can probably tell from a previous post, I’m not a fan of paywalls—especially poorly implemented ones. Clicking on a link in an RSS feed post and having it land on a page, only to have it smothered in an HTML layer or — in the following case — promptly redirected to “Pay up, buddy!” sites is frustrating at best. I’ll gladly debate the efficacy of paywalls vs other means of generating revenue in another post (or even in the comments, if civil). I primarily wanted to write this post to both show the silliness of the implementation of Foster’s Daily Democrat’s paywall and point out a serious deficiency in Chrome.

First up, lame paywall. You get three free direct story link visits prior to be asked to register and eventually pay for content. NOTE: You could just be going to the same story three times (say, after a browser crash) and each counts as a visit. After those visits, you have to register and give up what little anonymity you have on the Internet to be able to view up to an additional ten free direct story links before then being forced to pay up. If you are a print subscriber, you do get access for “free”, but there’s that tracking thing again. Foster’s uses a service called Clickshare to handle the subscription and tracking. Just how many places do you need to have your data stored/tracked just to read a (most likely) mediocre piece of news?

The paywall setup is accomplished by a simple “Meta Refresh” tag. In its most basic form, it is an instruction that tells the browser to load a particular URL after a certain amount of time. In the case of Foster’s paywall, the HTML tag/directive looks like this:

[code lang=”html”]<meta http-equiv="refresh" content="0;url=https://home.fosters.com/clickshare/authenticateUserSubscription.do?CSAuthReq=1&CSTargetURL=…"/>[/code]

It’s telling your browser to double-check with their Clickshare code immediately after teasing you with the article content. And, it’s easy to circumvent. Mostly. The problem is, I’m a Chrome user 99% of the time and Google has not seen fit to allow control over the meta refresh directive. To jump the paywall, you’ll need to fire up Firefox. And enter “about:config” in the location bar (and click through the warning message).

Once there, filter for “refresh”, find the setting for “blockautorefresh” and set it to “true“.

Now, every time you visit a web site that attempts to auto-refresh full browser pages, you’ll see a warning (with the option to allow the action):

Why Chrome has not implemented a way to control this is beyond me. Since Safari also has no ability to control this setting, it may have something to do with the webkit core that both browsers are based on.

This doesn’t stop the frustration with the RSS-click-to-read and it doesn’t help iOS/Android users, but it does provide a means help keep a bit of anonymity (if you also use other extensions and controls) and should force these sites to kick their paywall game up a notch.

“Repairing” Strict Transport Security in Chrome on OS X

One of my subdomains is for mail and I was using an easy DNS hack to point it to my hosted Gmail setup (just create a CNAME pointing to ghs.google.com). This stopped working for some folks this week and I’ve had no time to debug exactly why so I decided to go back to a simple HTTP 301 redirect to avoid any glitches (for whatever reason) in the future – or, at least ensure the glitches were due to any ineptness on my part. Unfortunately, this created an interesting problem that I had not foreseen.

I started playing with Strict Transport Security (HSTS) a while ago and – for kicks & some enhanced WordPress & Drupal cookie security – moved a couple domains to it. I neglected to actually pay for a cert that would give me wildcard subdomain usage and only put in a couple domains for the cert request. I neglected to put the mail one in and that caused Chrome to not honor the redirect due to the certificate not being valid for the mail domain.

I tweaked theStrict-Transport-Security header setting in my nginx config to not include subdomains, but it seems Chrome had already tucked the entry into (on OS X):

[code padlinenumbers=”false” gutter=”false”]~/Library/Application Support/Google/Chrome/Default/TransportSecurity[/code]

and was ignoring the new expiration and subdomain settings I was now sending. Again, no time to research why as I really just needed to get the mail redirect working. I guessed that removing the entry would be the easiest way to bend Chrome to my will but it turns out that it’s not that simple since the browser seems to hash the host value:

[code]"wA9USN1KVIEHgBTF9j2q0wPLlLieQoLrXKheK9lkgl8=": {
"created": 1300919611.230054,
"expiry": 1303563439.443086,
"include_subdomains": true,
"mode": "strict"
},[/code]

(I have no idea which host that is, btw.)

I ended up backing up the TransportSecurity file and removing all entries from it. Any site I visit that has the cookie will re-establish itself and it cleared up the redirect issue. I still need to get a new certificate, but that can wait for another day.

Windows and Linux folk should be able to find that file pretty easily in their home directories if they are experiencing any similar issue. If you can’t find it, drop a note in the comments and I’ll dig out the locations.

“Web Development Is Dangerous”

Those were the words that greeted me within five minutes of checking out the Flask microframework for Python web applications. I feel compelled to inline those four, short paragraphs:

I’m not joking. Well, maybe a little. If you write a web application, you are probably allowing users to register and leave their data on your server. The users are entrusting you with data. And even if you are the only user that might leave data in your application, you still want that data to be stored securely.

Unfortunately, there are many ways the security of a web application can be compromised. Flask protects you against one of the most common security problems of modern web applications: cross-site scripting (XSS). Unless you deliberately mark insecure HTML as secure, Flask and the underlying Jinja2 template engine have you covered. But there are many more ways to cause security problems.

The documentation will warn you about aspects of web development that require attention to security. Some of these security concerns are far more complex than one might think, and we all sometimes underestimate the likelihood that a vulnerability will be exploited, until a clever attacker figures out a way to exploit our applications. And don’t think that your application is not important enough to attract an attacker. Depending on the kind of attack, chances are that automated bots are probing for ways to fill your database with spam, links to malicious software, and the like.

So always keep security in mind when doing web development.

Let’s look at the key take-away messages…

Data Should Be Stored Securely

Interestingly enough, this is not the default mindset of one of the more popular modern database technologies [mongoDB] (and it has plenty of company [memcached], too).

Even if your app starts out without any real sensitive data, odds are you will be storing credentials, e-mail addresses, social network handles and other bits of information that you should feel some fundamental responsibility to treat with care. There are somemcached manymysql resourcesoracle tocouchdb helpsqlite that you really have no excuse.

And, it will save you time later on when you realize you actually need to have a secure storage foundation.

Watch The Input To Your Apps

Flask protects you against one of the most common security problems of modern web applications: cross-site scripting (XSS). There are many others. If you are a programmer and have never even heard of OWASP, then you need to put down your PS3/Xbox controller and do a quick read on at least their take on the top ten web app security risks (btw: there are way more than ten, but you need to start somewhere).

The thing is, unless the halls of higher education have crumbled completely since I was in school, I distinctly remember having the concept of input validation, bounds checking, etc. being rammed into my thick skull in almost every programming class (and this was way before web apps were even contemplated). You may think you’re innovating by posting a link to your functioning rapid prototype on Hacker News, but what you’re really doing is being sloppy, lazy and irresponsible. Period.

And, while it’s fine to seek out frameworks like Flask and rely on some of their inherent protections, it does not absolve you from your responsibility to deliberately & consciously build rugged software (which doesn’t just mean “secure”).

“Don’t think that your application is not important enough to attract an attacker”

I’m not sure if any amount of verbiage will convince someone of this fact if they are determined not to believe/accept it. It’s a much larger discussion (and this is already a long post). If you are inclined to have a slightly open mind, I encourage you to read So You Think Your Website Won’t Get Hacked by Joseph Schembr. It’s really slanted towards “script-kiddies,” but should pique your interest enough to keep exploring why your hacked-up personal URL shortener might be a target.

Fin

It’s impressive that the Flask authors cover security in some way, shape or form on 21 pages in the documentation [PDF]. If you’re building or contributing to other frameworks, projects or engines (hint, hint, Node.JS devs!) I would strongly encourage you to take as much time and consideration as the Flask team did to ensure you are making it as easy as possible for your users to deploy applications as securely as possible by default.

AwesomeChartJS Meets Microsoft Security Bulletins

I wanted to play with the AwesomeChartJS library and figured an interesting way to do that was to use it to track Microsoft Security Bulletins this year. While I was drawn in by just how simple it is to craft basic charts, that simplicity really only makes it useful for simple data sets. So, while I’ve produced three diferent views of Microsoft Security Bulletins for 2011 (to-date, and in advance of February’s Patch Tuesday), it would not be a good choice to do a running comparison between past years and 20111 (per-month).  The authors self-admit that there are [deliberate] limitations and point folks to the most excellent flot library for more sophisticated analytics (which I may feature in March).

The library itself only works within an HTML5 environment (one of the reasons I chose it) and uses a separate <canvas> element to house each chart. After loading up the library iself in a script tag:

<script src="/b/js/AwesomeChartJS/awesomechart.js" type="application/javascript">

(which is ~32K un-minified) you then declare a canvas element:

<canvas id="canvas1" width="400" height="300"></canvas>


and use some pretty straighforward javascript (no dependency on jQuery or other large frameworks) to do the drawing:

var mychart = new AwesomeChart('canvas1');
mychart.title = "Microsoft Security Bulletins Raw Count By Month - 2011";
mychart.data = [2, 12];
mychart.colors = ["#0000FF","#0000FF"];
mychart.labels = ["January", "February"];
mychart.draw();

It’s definitely worth a look if you have simple charting needs.

Regrettably, it looks like February is going to be a busy month for Windows administrators.

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