February 23, 2019

Adobe Flash Cookies: Yes They Are Dangerous, and More Cool Linux Hacks - page 2

What Happens When You Disable Flash Cookies

  • March 30, 2009
  • By Carla Schroder

As usual when the subject is Linux regular expressions and fun commands (like in part 2), readers chime in with their own ingenious variations. Another way to block Flash cookies completely from nesting on your hard drive is to use the time-honored tactic of directing them to /dev/null with a symbolic link, which you can create by first deleting the ~/.macromedia directory and all of its contents, and then creating the soft link:

$ rm -rf ~/.macromedia
$ ln -s /dev/null .macromedia

Verify it with the ls command:

$ ls -ald .macromedia
lrwxrwxrwx 1 carla carla 9 2009-03-30 09:56 .macromedia -> /dev/null

If you followed the instructions in Part 2 to set your ~/.macromedia directory to read and execute only, you'll get a "permission denied" error when you try to delete it. Fix that by giving it write permissions:

$ chmod -Rv 0700 ~/.macromedia

If you care to dig through your Flash cookies manually and identify ones that you want to keep, which isn't too hard because their directory names include the originating domains, you can modify the find invocation we used in Part 2 to not delete them:

$ find -iname '*.sol' -not \( -name filename -o -name filename \) -exec rm "{}" \;

-o means or and -name means "this is the filename", so if you have more than one file you want to keep, list them separated by -o -name.

More Information

Adobe have been #1 on my Do Not Like/Boycott Forever list ever since they had Dmitri Sklyarov imprisoned and prevented from going home to Russia for over five months for giving a presentation (at DefCon, Las Vegas) on weaknesses in Adobe's eBook encryption software. Real criminals routinely get away with serving less time than Mr. Sklyarov did, and he was never convicted of a crime. Adobe execs to this day have not apologized or offered reparations; rather, they had charges brought against Mr. Sklyarov's employer, ElcomSoft. Mr. Sklyarov was not released or allowed to return home until he agreed to testify against ElcomSoft.

The next time you hear someone going on about how extremist and out-of-touch Richard Stallman is for being a strong advocate of software and technology freedom, remember this case.


A very informative article by Rob Savoye, the main Gnash developer: "Looking at my list, I see over 100 websites that have been accessing the same cookie for the last year (the last time I formatted my computer)."
US v. ElcomSoft & Sklyarov FAQ
Flash Player update available to address security vulnerabilities
Adobe Flash zero-day exploit in the wild

Carla Schroder is the author of the Linux Cookbook and the Linux Networking Cookbook (O'Reilly Media), the upcoming "Building a Digital Sound Studio with Audacity" (NoStarch Press), a lifelong book lover, and the managing editor of LinuxPlanet and Linux Today.

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