Shell in a box

Shell in a Box allows you to control a computer over the network using a Linux console in a web page. To do it, find out your distribution and proceed accordingly.

SUSE 12.1

Get it

• open a console as root.

• Download shell in a box from google

wget http://shellinabox.googlecode.com/files/shellinabox-2.11.tar.gz

• unpack it

tar xvzf shellinabox-2.11.tar.gz

• install some dependencies, in this example for SUSE Linux 12.1:

yast -i make

• build it

cd shellinabox-2.11
./configure && make && make install

• make sure the firewall is open, here is an example for SUSE Linux:

rcSuSEfirewall2 stop

• add a user for shell in a box, in this example user

useradd -m user
passwd user

• call shell in a box

cd /tmp
shellinaboxd &

• test it by surfing to your computer: http://localhost:4200

• now set up apache for https so your passwords are not transmitted unencrypted over the internet

Make it persistant

You want the shell in a box daemon shellinaboxd to be started when booting your machine, so

• add the following line to /etc/init.d/boot.local:

shellinaboxd &

• configure the firewall to always open up port 80 or stop it persistantly:

chkconfig SuSEfirewall2_setup off
chkconfig SuSEfirewall2_init off

• configure apache to start on boot

chkconfig apache2 on

Co-exist with a web server

You probably want shell in a box to be reachable via port 80 (so you can use it from within a typical corporate network) and you may want to run a web server on the same machine. So here is how you integrate shell in a box into an Apache2 web server

• install apache2, in this example for SUSE Linux 12.1:

yast -i apache2

• enable a reverse proxy. To do this, edit /etc/sysconfig/apache2 and add the following words to APACHE_MODULES: proxy proxy_http. In the end your line may read like this:

APACHE_MODULES="actions alias auth_basic proxy proxy_http authn_file authz_host authz_groupfile authz_default authz_user autoindex cgi dir env expires include log_config mime negotiation setenvif ssl userdir php5"

• tell apache that if someone calls http://yourserver.yourdomain/shell this is forwarded to http://yourserver.yourdomain:4200 internally. To do this, edit /etc/apache2/default-server.conf, add a block

<IfModule mod_proxy.c>
<Location /shell>
    ProxyPass http://127.0.0.1:4200
</Location>
</IfModule>

Ubuntu

Get it

• open a console as root.

• Download shell in a box from google

wget http://shellinabox.googlecode.com/files/shellinabox-2.11.tar.gz

• unpack it

tar xvzf shellinabox-2.11.tar.gz

• install some dependencies, in this example for SUSE Linux 12.1:

yast -i make

• build it

cd shellinabox-2.11
./configure && make && make install

• add a user for shell in a box, in this example user

useradd -m user
passwd user

• call shell in a box

cd /tmp
shellinaboxd &

• test it by surfing to your computer: http://localhost:4200

• now set up apache for https so your passwords are not transmitted unencrypted over the internet

TroubleShooting

Symptom: ShellInABoxD does not start, it tells the error message:

Cannot read valid certificate from "certificate.pem". Check file permissions and file format.

Reason: See http://code.google.com/p/shellinabox/issues/detail?id=59. ShellInABoxD tries to create a file certificate.pem in the folder where it is started as user nobody:

/tmp # ll certificate.pem 
-rw------- 1 nobody nogroup 2794 Aug  5 07:53 certificate.pem

Solution: Start shellinaboxd in a directory that every user can access, e.g. /tmp:

cd /tmp
shellinaboxd &

Co-exist with a web server

You probably want shell in a box to be reachable via port 80 (so you can use it from within a typical corporate network) and you may want to run a web server on the same machine. So here is how you integrate shell in a box into an Apache2 web server

• install apache2

apt-get install apache2
ln -s /etc/apache2/mods-available/proxy_http.load /etc/apache2/mods-enabled/proxy_http.load

See also

• http://code.google.com/p/shellinabox/