binfalse

The aircrack tool unfortunately does not have a suspend or pause mechanism, thus as soon as you stop it you need to start again from the very beginning. Of course, you may manually adjust the dictionary, but that’s tedious and “error prone”.. ;-)

Lucky us, there is john the ripper to give us a hand. John knows about sessions. Just start a run which prints the words in the dictionary one after the other:

john --session=somename --stdout --wordlist=dictionary

Stop the run at any point in time using e.g. Ctrl+c and john will store the information about the session. Just return the session with --restore:

john --restore=somename

and john will continue from where it was stopped.

To make aircrack read the words from stdin use -w -. A typical run might look like

# start john
john --session=somename --stdout --wordlist=dictionary | aircrack-ng -w - handshake.cap -b 01:12:23:34:45:56
# kill the run
^C
# restart from where is was stopped
john --restore=somename | aircrack-ng -w - handshake.cap -b 01:12:23:34:45:56

Just wanted to install a ruby package using gem. However, I’m not a ruby dev and it took me a while to work around a certain problem with gem..

I wanted to install the Effing Package Management:

% gem install fpm
Building native extensions.  This could take a while...
ERROR:  Error installing fpm:
        ERROR: Failed to build gem native extension.

    /usr/bin/ruby2.1 extconf.rb
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
        --with-opt-dir
        --without-opt-dir
        --with-opt-include
        --without-opt-include=${opt-dir}/include
        --with-opt-lib
        --without-opt-lib=${opt-dir}/lib
        --with-make-prog
        --without-make-prog
        --srcdir=.
        --curdir
        --ruby=/usr/bin/ruby2.1
        --with-ffi_c-dir
        --without-ffi_c-dir
        --with-ffi_c-include
        --without-ffi_c-include=${ffi_c-dir}/include
        --with-ffi_c-lib
        --without-ffi_c-lib=${ffi_c-dir}/lib
        --with-libffi-config
        --without-libffi-config
        --with-pkg-config
        --without-pkg-config
/usr/lib/ruby/2.1.0/mkmf.rb:456:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
        from /usr/lib/ruby/2.1.0/mkmf.rb:541:in `try_link0'
        from /usr/lib/ruby/2.1.0/mkmf.rb:556:in `try_link'
        from /usr/lib/ruby/2.1.0/mkmf.rb:642:in `block in try_ldflags'
        from /usr/lib/ruby/2.1.0/mkmf.rb:635:in `with_ldflags'
        from /usr/lib/ruby/2.1.0/mkmf.rb:641:in `try_ldflags'
        from /usr/lib/ruby/2.1.0/mkmf.rb:1762:in `pkg_config'
        from extconf.rb:15:in `<main>'

extconf failed, exit code 1

Gem files will remain installed in /var/lib/gems/2.1.0/gems/ffi-1.9.6 for inspection.
Results logged to /var/lib/gems/2.1.0/extensions/x86_64-linux/2.1.0/ffi-1.9.6/gem_make.out

Especially line 35 drove me insane: You have to install development tools first. That made me think I need to install more *-dev stuff. Took me some time to find out that there was a problem with gcc! Turns out that gcc version 4.8.3 (Debian 4.8.3-13) (gcc -v) wasn’t able to build the package for me. So I installed gcc version 4.9.1 (Debian 4.9.1-19) and everything worked like a charm. :)

Just discovered a nice way to take screenshots of web sites from the command line! No browser needed. Cool.

The tool I’d like to advertise is called gnome-web-photo :

aptitude install gnome-web-photo

For instance. To take generate an image of my website just call:

gnome-web-photo --timeout=60  binfalse.png

Just take a look at binfalse.png to examine the result. I obtained a 1024x6334 image. I guess the main use case is to generate some kind of preview/thumbnail. To get a thumbnail simply add --mode=thumbnail :

gnome-web-photo --timeout=60 --mode=thumbnail  binfalse-thumb.png

Afaik, there is no option to generate a larger thumb, but you could just pass --width= without the --mode=thumbnail . And then crop the pic yourself (e.g. using imagemagick). However, you need to run X and you need to have GTK, if I understand correctly. Nevertheless, I like that solution.

I just needed to record a video stream. Usually, I use mplayer for these kinds of jobs, but this time it failed. However, on the internet I found a way to do it using VLC, which apparently has quite a command line interface.

This comment revealed that the VLC media player comes with some command line magic. Of course, not much is documented in the man page, but the user guide on their website seems to be useful.

Long story short, I ended up with the following command to save the stream http://STREAM.mp4 to /tmp/file.mkv :

vlc http://STREAM.mp4 --sout="#std{access=file,mux=mkv,dst='/tmp/file.mkv'}" vlc://quit

Cool.

For the records, here are some alternatives:

# using mplayer
mplayer -dumpstream http://STREAM.mp4 -dumpfile /tmp/file.mp4
# using ffmpeg
ffmpeg -i http://STREAM.mp4 -acodec copy -vcodec copy /tmp/file.mp4

It was time to finally replace my old GPG key. I created the key in 2008 and from today’s perspective a 1024 bit DSA key is really weak. Thus, today I decided to move to a new key and created a 4096 bit RSA key.

My old key was

pub   1024D/446DB306 2008-07-15 [expires: 2017-07-13]
      Key fingerprint = 0E75 62A5 405E 65B1 B477  4215 D9B3 5173 446D B306

And the new key is:

pub   4096R/8D2DD9BD 2014-01-15 [expires: 2019-01-14]
      Key fingerprint = 08E6 6E72 A83A 9871 CD49  3441 E81B C307 8D2D D9BD

For those of you who already trust my old key I created a transition note which is signed by both my old and my new key.

To import my new key to your key chain you can use the following command:

gpg --keyserver pgp.mit.edu --recv-key 8D2DD9BD

The new key is already signed by the old key. Those of you trusting my old key may verify the signature using:

gpg --check-sigs 8D2DD9BD

To sign the new key execute the following command:

gpg --sign-key 8D2DD9BD

And it would be nice if you upload the signed to one of the key servers:

gpg --keyserver pgp.mit.edu --send-key 8D2DD9BD

You are of course free to give me a call in order to verify the fingerprint ;-)