Web - re: nyman

Conditional access using only nginx
Mar 13, 2021
Have you ever wanted to deploy a website to test that it works, without everyone else being able to see it?

If you are using a dynamic language or CMS for your webpage (PHP, Wordpress or Ruby on Rails) there are straightforward ways to accomplish this.

But what happens if you have a static webpage? Here I will present one solution using only a nginx config file to accomplish this.
```
# first we need to allow access to the soon.html
# and also a logo which is linked from the soon.html
# if your soon.html links more resources in this server
# you need to update the regex to match that also
location ~ /(soon\.html|images/logo_white.png) {
    try_files $uri =404;
}

# this is the secret way to get past the block
# it will set a magic cookie with a lifetime of 1 month
# and redirect back to the host  
location /iwanttobelieve {
  add_header Set-Cookie "iwantto=believe;Domain=$host;Path=/;Max-Age=2629746";
  return 302 $scheme://$host;
}

# this is the normal serve, but with a condition that everything
# everyone that does NOT have the magic cookie set will be served
# the content of soon.html
location / {
if ($http_cookie !~* "iwantto=believe") {rewrite ^ /soon.html last; }
	try_files $uri $uri/ =404;
}
```
That it! Copy and paste the above into a server {} block. Make sure to take not of the order though to ensure you don’t have anything else before this which would take precedence. Then change all occurrences of soon.html if you use something else. And remember that the first match needs to match everything that this soon.html tries to reference, otherwise they will just get back the content of /soon.html for all other requests.

Note that if is a bit finicky in nginx, check their documentation for more details.
Usability > Security
Feb 7, 2021
Introduction

The other day I wanted to use my noscript.it with one of my old iPhone 4S running iOS 6, but I was met with “could not establish a secure connection to the server”.

Turns out it was because I had, out of habit, configured the server with a “modern” list of TLS ciphers. And the poor old iOS 6 didn’t support any of them.

So, I went on a mission to ensure noscript.it works with as old devices as possible.

It turns out enabling TLS1 and TLS1.1 on Ubuntu 20.04 is a bit harder than I expected¹. Luckily someone else solved it already.

So now, after using the old mozilla SSL config and appending @SECLEVEL=1, it works. Even on my vintage iPhone 3G. Hurray!

Wait what?

But, I hear you say, isn’t this less secure? I mean now you only get a B on the Qualys SSL Report! Clearly this is bad!?

Let’s take a step back and think about what the score actually means. noscript.it automatically gets a B because it supports TLS1. But let’s go one step further and assume we’re looking a bank with a C². A site gets a C if it supports SSLv3, meaning it is vulnerable to the SSLv3 POODLE³ attack. This is clearly bad for a bank!? Or is it? How likely is it that someone will successfully execute this attack, which requires the attacker to have the ability to intercept and modify the data transmitted. And compare this likelihood with how likely is it that someone will need to access the bank website from an old XP (pre-SP3) machine only supporting SSLv3? The second seems more likely to me.⁴

Okay, you say, but won’t keeping SSLv3 around make everyone vulnerable because of downgrade attacks? If that were the case, the risk calculation would be different. But luckily, we have TLS_FALLBACK_SCSV to avoid that. TLS_FALLBACK_SCSV ensures that modern client and browser won’t risk being fooled to downgrade its encryption.

Conclusion

So to wrap things up, don’t stare blindly at the rating or certification. A site with A++ is more secure than one with a C rating. But if you (or someone less fortunate) can’t access the site when they need it, it will be a pretty useless site. Personally, from now on, unless the site needs ⁵ absolute security, all my projects will optimise for compatibility rather than getting an A++. After all, it is much more likely someone will try using it with a Windows XP or old Smart-TV compared to someone MITM-ing that person at that moment.

Disclaimer

Please note though, don’t read this as an argument against doing things securely as default and following best practices. Rather it is just some thoughts on this specific issue of TLS and SSL configurations. If you break with best practice, make sure you understand the reason why it’s best practice to begin with and what risks or weaknesses you introduce by not following them.
1. I 100% support secure defaults, make it hard to do the wrong thing. ^[return]
2. A favourite hobby of some people in the security community is to publicly shame banks or websites for not getting a great grade in the Qualys SSL test. Here is an example from Troy Hunt ^[return]
3. SSLv3, not to be confused with the POODLE attacks against some weak TLS implementations. ^[return]
4. Also there are mitigations which you should of course implement unless it breaks more than it fixes. ^[return]
5. in some cases, like highly sensitive data or targeted users the risk calculation will be different, it might be better for a user not to be able to use the site rather than risk some known (or unknown) attack. ^[return]
Introducing PISS, a PHP KISS static page generator
Oct 11, 2020
There are lots of static page generators, I personally used Hugo and there like 100 others. But I had a project where I wanted something even simpler, and had a few requirements. I wanted to
1. Write raw HTML/CSS
2. Update things in one place only (e.g. don’t copy paste the menu to each html file).
For 1, you don’t need anything other than an editor. 2 is where you need something more than HTML.

I recently came across a project that promised to do more or less exactly what I wanted, xm

But it was written in node/javascript, so I went to look for something else.¹

After not finding anything similar, I decided to to do it myself in the 4th most dislike programming language, PHP.

PHP is ubiquitous on Linux servers, and it’s great at generating HTML. The downside for using it as a static page generator is… that it’s not static.

Each time you request a .php page, php will compile and interpret the code and return the output.

The first and obvious solution is to just store the output as html, and you turned it in to a static page generator. Like so

php page.php > page.html

This might get tedious though, and although you can just do a build system which does it, I got curious if it would be possible to do it “on-demand”.

And as a challenge to myself, I wanted to see if it would be possible if I could make it small enough to fit in a tweet² and without any other dependencies than PHP.

And without further ado, I present to you,

PHP keep It Stupid Simple, in short PISS.
```
<?php
ob_start(
    function($output) {
        $t = substr(__FILE__, 0, -4) . '.html';
        ($f = fopen($t, 'w')) || header("HTTP/1.1 500") && exit(1);
        fwrite($f, $output);
        header("Location: " . substr($_SERVER['REQUEST_URI'], 0, -4 ) . ".html");
    }
);
?>
```
Because this is a Real-Serious-Project™ it’s available on GitHub with an issue tracker and all other features that a Real-Serious-Project™ needs.
1. Mostly because I am not familiar with node/js, but also because xm had 125 dependencies so it failed my requirement of keeping it simple. ^[return]
2. The modern variant of 280 characters, not 140, I’m not that good at this. ^[return]
Aug 6, 2020

lol what?

font-family: monospace, monospace

Is not the same as

font-family: monospace

I’m so happy there are other people who figure these things out. https://stackoverflow.com/questions/38781089/font-family-monospace-monospace

Conditional access using only nginx

Usability > Security

Introduction

Wait what?

Conclusion

Disclaimer

Introducing PISS, a PHP KISS static page generator