Clear-Site-Data HTTP Header

In an effort to improve security on the client-side modern browsers have introduced a means to allow for web applications request a client to remove persisted data. Of course, not supported in any version of MSIE or Safari, but all modern browsers Chrome 61+, Edge 79+, Firefox 63+ support.

This approach can be useful at logoff or session invalidation to remove data from the client-side, particularly in cases of persistent or reflected XSS.

Clear-Site-Data: "cookies"
Clear-Site-Data: "cache", "cookies", "storage", "executionContexts"

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Remove language packs from Windows 7

I often have to install different languages/locales on Windows 7 to perform testing in different languages, unfortuately adding all of them into a single installation can take a lot of space, particularly when using a virtual machine.

Using the usual method to ‘remove installed software’ will remove updates, but leaves the languages in place, to completely remove them you must open a command prompt and execute the following:


LPKSETUP

Select the languages you wish to remove, and click continue… it will take a while, but the languages will be removed one at a time.

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Remove Guest Account in Ubuntu

While the Guest session can be useful for some people, I’ve generally considered it to be security vulnerability as unauthorized users could gain physical access to some areas of your system that are not secured as well as they “should” be.

Additionally, the default behavior that allows for the username(s) to be stored and listed on the login screen are less than ideal.

Here we remove both!

  1. Create the config folder:
    sudo mkdir -p /etc/lightdm/lightdm.conf.d
  2. Create a new config file:
    sudo vi /etc/lightdm/lightdm.conf.d/10-ubuntu.conf
  3. Add the following:

    [SeatDefaults]
    user-session=ubuntu
    greeter-show-manual-login=true
    greeter-hide-users=true
    allow-guest=false
  4. Reboot

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Force cleaning of workspace during automated Maven builds

I’ve been using Maven for years, but once in a while forget to ‘clean‘ before building, resulting in old artifacts being included in the output. This can be problematic when refactoring for security items. Thankfully, it is very easy to add a ‘clean‘ step to your pom.xml to force clean each build.

BONUS – the plugin has some additional capabilities, specifically you can specify files outside of ‘target’ to be removed. This can be useful for any custom reporting or logging that you might create.

The Maven clean plug-in can be added to the pom.xml as such:

<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-clean-plugin</artifactId>
<version>${maven-clean-plugin.version}</version>
<executions>
<execution>
<id>auto-clean</id>
<phase>initialize</phase>
<goals>
<goal>clean</goal>
</goals>
</execution>
</executions>
</plugin>

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Remove Landscape on Ubuntu

The Canonical/Ubuntu Landscape service has been around for as long as I can remember using Ubuntu. A free trial period is enabled (re-enabled?) when a new installation occurs, that allows for a server administrator to see performance metrics and uptime information for any hardware that is running the client. After the trial ends, it is still a quick means of visually observing some key statistics in the terminal MOTD at login. I’d also noticed that it was still doing DNS lookups to “landscape.canonical.com” on a regular basis, and while I did not look for it, I assume that some information was still being collected and reported upon.

As there are MANY other ways to get server performance information, I decided that it was time to be rid of landscape itself.

Removal is easy, as only one line is required… I chose to “purge” all references, though you can “remove” if you feel inclined to leave any configuration for possible later re-installation.


sudo apt-get purge landscape-client landscape-client-ui landscape-client-ui-install landscape-common

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HTML table cellspacing and cellpadding in CSS

As I often find myself cleaning up legacy webapp codebases, this item seems pretty common, particularly for sites that were using TABLE based layouts.


<table cellpadding="0" cellspacing="0">
<thead>
<tr><th>Hello</th></tr>
</thead>
<tbody>
<tr><td>World</td></tr>
</tbody>

With modern browsers, this is easily accomplished with some simple CSS, as you might need some distinction between different tables or have some cases that require padding or spacing, you MIGHT consider assigning a CSS class as I have below.


<style type="text/css">
table.modern{
border-collapse: collapse; /* 'cellspacing=0' equivalent */
}
table.modern td,
table.modern th{
padding: 0; /* 'cellpadding=0' equivalent */
}
</style>

<table class="modern">
<thead>
<tr><th>Hello</th></tr>
</thead>
<tbody>
<tr><td>World</td></tr>
</tbody>

Linux/Windows file cleanup

If you make heavy (or even typical) use of your computer, you’ll often notice that it just doesn’t seem as fast as it once was. For a slight increase in performance, disk space and to generally remove some of the ‘temporary’ files/cruft that are routinely written to disk you have a few options.

Here are a few of my current favorites for doing ‘Spring Cleaning’ on my computers… BleachBit and CCleaner

BleachBit is available on all major platforms (Windows, OS/X, Linux).