Archive for category Open-Source
Ways for Tracking your Stolen Laptop
Posted by Mourad Ben Lakhoua in Open-Source, Safety rules, Tools on August 25, 2010
Getting back your lost laptop is always possible, for mobile devices it is easier to find it because of IMEI number which can identify your device on the GSM Network and it can be displayed by entering *#06# into the keypad on most phones. Changing this unique number is possible but not simple.
Now for the Notebook things are getting more serious because without a special technique you cannot track you laptop or computer, at each network there is a getaway and even if you will have access to all cities getaway logs you should look at the Mac address of your Network devices, well this is not simple.
Creating a VPN will solve the issue because when your laptop boots it will search for the VPN server on Internet and you can get by IP the location of your laptop, LogMeIn Hamachi² which is a hosted VPN service that securely connects devices and networks, extending LAN-like network connectivity to mobile users can help in performing this.
Well this comes as one solution but for sure there are many, another Open Source and free project that can track any Machine using any operating system is Prey, Prey helps you locate your missing laptop by sending timed reports with a bunch of information of its whereabouts. This includes the general status of the computer, a list of running programs and active connections, fully-detailed network and wifi information, a screenshot of the running desktop and — in case your laptop has an integrated webcam — a picture of the Gangsters.
Prey uses a remote activation system which means the program sits silently in your computer until you actually want it to run. If so, it gathers all the information and sends it to your Prey web control panel or directly to your mailbox. The thief will never know his movements are being watched.
The last very useful tool is TeamViewer which gives you the opportunity to connect your laptop even if you don’t know the IP address so you can have the location and turn on your webcam to see who is sitting in front of your Laptop.
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Keep Your Unix-Based System Safe This Summer (Part2)
Posted by Mourad Ben Lakhoua in Best Practices, Open-Source, Operating System, Safety rules, Software Security on July 5, 2010
System monitoring is the most important method for detecting all kinds of Trojans, viruses and any malicious activities on the system.
Maintaining control over file integrity can be acheived by installing a tripewire which has the ability to detect changes on each system on which it is installed, checks the integrity of normal binaries and reports any changes to syslog or by email, and alerting users to intrusions and unexpected changes with the available source code.
After installing the tripwire (using command: $ Sudo apt-get install tripwire) you will need to answer some questions regarding the configuration, and by the end you need to enter a password of at least 8 characters (twice).
The script generates keys for your site (host) and then asks you to enter a password (twice) for local use. You should then back up and delete the original plain-text files installed on the system.
Developers have made the appropriate policy for all files and configurations, but if you need to update or change something you can make the change at the file in /etc /tripwire/tw.pol.
Actually, the tripwire creates a database with snapshot of your file system, it uses this baseline along with the encrypted configuration and policy settings under the /etc/tripwire directory to monitor the status of your system.
Now you can perform a test scan:
$ Tripwire – check
The check will be on a daily bases and will report all changes, including the normal tasks allowed once like editing system configuration files, installing packages, etc … and all reports on the changed files will be sent to the root by email.
Final three points are:
* Keeping track of all access accounts, all important system configuration files should be readable and writable only by root. Home directory can be accessed only by you (600).
* Do not place users in many groups because group membership gives users special access to files and directories which are permitted to that group. Such as operator, audio, etc, this can creates a hole and gives user a special privilege not needed.
* Root privileges are needed only when they are really required. No need to run commands as root and if you really need to install or manipulate something, use sudo.
So make sure to apply all these security rules for a safe 2010 Summer.
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(Picture from Scott Ableman)
Keep Your Unix-Based System Safe This Summer (Part1)
Posted by Mourad Ben Lakhoua in Best Practices, Open-Source, Safety rules on June 27, 2010
Protecting your systems against all manner of intrusions will provide more safety for your virtual life, by using complex passwords and a regular file check against changes, plus restricting anything and everything will keep these threats away.
Computersremain the easiest point to compromise if there is a physical access. At schools, universities, cafes or the airport many people use their computers without locking the session.
Lock screen comes as the first and most important reflex to protect your machines physically. Locking the screen is possible over a keyboard combination:
Ctrl+Alt+L (KDE and Gnome) and Ctrl+Alt+Del (Xfce). The same can be done from the command line: KDE $ qdbus org.freedesktop.
ScreenSaver / ScreenSaver Lock
Gnome $ gnome-screensaver-command-l
Xfce $ xflock
For other cases, you can use the command:
$ Xscreensaver-command-lock
Or you can install program from xlock, xscreensaver if not activated. The console is an analog vlock. This will help in Locking Popular text window managers, such as GNU Screen and Tmux that we mentioned on a previous post.
Locking the screen will not bring much benefit if we are keeping the Boot from CD/USB on Bios level enabled, because there are many Linux Live CD that can help in removing different session passwords.
Booting from any media except from the hard disc should be disabled, and set a password on the CMOS setup. For better reliability, reset the file/etc/security where entry is possible under the account root.
If a person managed to steal your password, you can use command last to display a list of all users logged in (and out) since that file was created or check file (~ /. history, ~ /. bash_history) for logs.
Then there are some important things to do while Installing or using the system:
1 – Do not click on icons that you do not know, as various malicious commands UNIX-shell that can be masked.
2 – Do not use the configuration files without reading them.
3 – Do not install software patches without reading their contents, or at least make sure that they were obtained from reliable sources. There is no guarantee that the patch does not contain backdoors, malicious code.
4 – Do not install packages manually from other websites. All normal distribution has a remote repository, in which all packages have a verification hash code. In an extreme case, download the package from sites that identify themselves using certificates.
5 – Always download into a temporary subdirectory of your home directory and check their content before unpacking.
6 – Create a file «-i» in the root directory (touch /-i). This will make as user permission before deleting each file in the root directory.
In next part we will be looking further for different configuration to make your Unix-Based system safe this summer.
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Logging/monitoring/handling Multiple Interactive Shells
Posted by Mourad Ben Lakhoua in Open-Source on June 22, 2010
GNU Screen is one of the favored tools for system administrators and Unix-based users. It is very popular and many articles have been published about it in the most reputable magazines and journals.
Now what makes this tool powerful? Why do so many users prefer it while so few people even know about it?
Nowadays, at different data centers, there is a large number of servers and applications that carry out different business requirements.
Imagine that you have a dozen of remote machines, and that you need to connect to them on a daily bases over SSH client to perform different tasks (checking logs, processes or evaluating the performance).
GNU Screen works perfectly for these situations because it is a terminal multiplexer. You can use it to run any number of console based applications, curser-based applications, text editors etc…
All you need to do is to connect to the remote machine and run command screen, click < Ctrl+AC>, to create a new window, run it, click top… etc. At any time you can click < Ctrl+AP> to return to a previously opened window. All within a Secure Shell connection SSH.
The real power for GNU Screen is in the supporting the sessions. At any time you can click < Ctrl+AD>, to disconnect from Screen and restart it with ‘r’ to resume an interrupted session with all the windows open, and not an altered state of applications.
All sessions will remain on the server, so it does not matter from which machine it will be restarted. You start the session at work, then go home to continue what you have started at the office this helps to make your work flexible.
OpenBSD starting from version 4.6 integrates Screen in the operating system which is named tmux. tmux major features include:
* A powerful, consistent, well-documented and easily scriptable command interface.
* A window may be split horizontally and vertically into panes.
* Panes can be freely moved and resized, or arranged into one of four preset layouts.
* Support for UTF-8 and 256-colour terminals.
* Copy and paste with multiple buffers.
* Interactive menus to select windows, sessions or clients.
* Change the current window by searching for text in the target.
* Terminal locking, manually or after a timeout.
* A clean, easily extended, BSD-licensed codebase, under active development.
Despite belonging to OpenBSD, tmux is able to work on a set of UNIX-based systems, including FreeBSD, NetBSD, Linux, Mac OS X, Solaris and AIX. Binary packages already available in the repositories of Debian Sid and Ubuntu Karmic, and the source can be obtained from the official website: tmux.sourceforge.net.
After running tmux, you will immediately notice the difference from Screen. First, the status bar is enabled by default, and includes almost all the information that should be added manually on screen. Secondly, there is a difference in the keyboard shortcut < Ca> will be < Cb>. But the other keyboard shortcuts are the same on Screen.
Using GNU Screen and tmux will greatly simplify all administration tasks. Not only allows running different terminal but creates a whole environment for managing the infrastructure.
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