Posts Tagged ‘open source’

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Hello folks,

In this article I will show you how to be a bit more secure (not 100%)* of your downloaded-content by torrent sites.

First of all, what is MD5 and MD5 checksum?

  • The MD5 message-digest algorithm is a widely used cryptographic hash function producing a 128-bit (16-byte) hash value, typically expressed in text format as a 32 digit hexadecimal number. MD5 has been utilized in a wide variety of cryptographic applications, and is also commonly used to verify data integrity. [wiki]
  • A checksum or hash sum is a small-size datum from a block of digital data for the purpose of detecting errors which may have been introduced during its transmission or storage. It is usually applied to an installation file after it is received from the download server. By themselves checksums are often used to verify data integrity, but should not be relied upon to also verify data authenticity. [wiki]

Every product has its own MD5 that is used to verify the data integrity of the file. The only thing that you have to do is a checksum. Both checksums should be equal for the same algorithm to calculate examples are : sha1, sha256, md5sum. The checksum value before downloading should be posted as part of the (meta) data or details of the file,  needed for verification of integrity purposes.

Checksum application:

  • gnu/Linux (ubuntu based): Υou have to go to the right directory where the downloaded file is and in the terminal you enter:
    ~$ cd "path.to.directory"

    Then put the exact name of the file:

    $ md5sum "name.exe"

After the comparison is done, the ouput should be like this

   8044d756b7f00b695abce8dce07d43e5 "name.exe"

If the hash matches with the provided by the website hash your download is not modified or corrupted.

  • MS Windows: You can use the File Checksum Integrity Verifier (FCIV) utility to compute the MD5 (or SHA-1) cryptographic hash values of a file or you can use one of the many windows checksum applications to make the verification.

Finally, you also have to check the number of the seeders / comments to see in some way the integrity of the torrent. The most “dangerous” file types are .exe, .bat, .msi.
Also keep in mind to have your pdf and java clients up-to-date to minimize the possible vulnerabilities threats.

*Keep in mind that there are also some md5 collisions created by the high number of hashes or by individuals, you have to check every character of the sum because at first sight the hashes may look the same.

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Type in terminal:

sudo nano /etc/apt/sources.list

Then replace everything there with:
# deb cdrom:[Debian GNU/Linux 7.0 _Kali_ – Official Snapshot i386 LIVE/INSTALL $
# deb cdrom:[Debian GNU/Linux 7.0 _Kali_ – Official Snapshot i386 LIVE/INSTALL $

## Security updates
deb http://http.kali.org/ /kali main contrib non-free
deb http://http.kali.org/ /wheezy main contrib non-free
deb http://http.kali.org/kali kali-dev main contrib non-free
deb http://http.kali.org/kali kali-dev main/debian-installer
deb-src http://http.kali.org/kali kali-dev main contrib non-free
deb http://http.kali.org/kali kali main contrib non-free
deb http://http.kali.org/kali kali main/debian-installer
deb-src http://http.kali.org/kali kali main contrib non-free
deb http://security.kali.org/kali-security kali/updates main contrib non-free
deb-src http://security.kali.org/kali-security kali/updates main contrib non-fr$

You will have something like this:

10854172_10152874573749035_602195891_othen ctrl+x to save the changes and press enter.

Then in terminal type

sudo apt-get upgrade

Then

sudo apt-get update

10844681_10152874594259035_189749895_o

And you are done. 🙂

TeamViewer, the popular software for remote support and online meetings, has reached version 9, receiving Wake-onLAN support, notifications for Computers & Contacts and more.

 

u-t2

TeamViewer is an application for remote control, desktop sharing, file transfer, online meetings and more, available for Windows, Mac OS X, Linux, Android and iPhone. The application is free for personal use only and on Linux, it uses Wine which comes bundled with it.

New features in TeamViewer 9: 

  • Wake-on-LAN;
  • two factor authentication for TeamViewer accounts;
  • support for Windows 8.1 and Mac OS X Mavericks;
  • save custom modules;
  • copy and paste files, images and text from one computer to another via the clipboard;
  • simplified file transfer without establishing a connection;
  • process customer cases in the service queue;
  • open multiple connections in tabs;
  • TeamViewer API for integration into your applications;
  • notifications available for Computers & Contacts – they notify you about new service cases, new contact requests, alerts about TeamViewer integrated monitoring checks and more.

 

Also, there’s a new design for both the TeamViewer and Computers & Contacts interface. According to the release announcement, important buttons convert automatically to a touch-friendly design when you use TeamViewer on a touch device.
Not all the new features are available on Linux though. For instance, in my test (both computers running Ubuntu) I wasn’t able to transfer files between the computers via copy/paste and the simplified file transfer seems to be missing. Also, opening connections in tabs seems to be a Windows-only feature.
 
The latest TeamViewer 9 also introduces QuickSupport for Linux users. With this, you can get instant support without needing to install TeamViewer and without admin rights:

 

teamviewer9ubuntu_thumb

 

Download TeamViewer 9

 

Note that older TeamViewer versions (6, 7, 8, etc.) can’t establish a remote connection with the latest TeamViewer 9. However, TeamViewer 9 users can establish remote connections with older versions.

 

Download TeamViewer (TeamViewer QuickSupport is available as a separate app on the same page)

Arch Linux users can install it via AUR (not updated to the latest version yet)

 

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ubuntu-flush-dnsHello guys,

Maybe you have notice that sometimes your network has trouble at reaching some or many websites.
An example of these is the common “404” error . This may be due to a corrupt local DNS cache.
I will show you some ways to clear your local DNS cache on some Operating Systems.

  • On GNU-linux / unix distros, we have to mention that there are many ways of DNS flushing, it depends on the OS. Flush nscd DNS cache:  nscd is able to speed up consecutive access to the same data dramatically and increase overall system performance. So lets restart nscd.

$ sudo /etc/init.d/nscd restart
OR
# service nscd restart
OR
# service nscd reload
OR
nscd -i hosts (Clear local DNS cache for current user)
nscd -I hosts (Clear local DNS cache for all users)

  • Mac OS X
    10.5.2 and above 
    (application -> utilities -> terminal)

sudo killall -HUP mDNSResponder

(To run this command, you will need to know the computer’s Admin account password.)

10.5.1 and below

sudo dscacheutil -flushcache

  • Windows 8(Press Win+X to open the WinX Menu then Right-click on Command Prompt and select Run as Administrator)

ipconfig /flushdns

  • Windows Vista / Windows 7(Right-click on Command Prompt and choose Run as Administrator)

ipconfig /flushdns

  • Windows XP(command prompt line, CMD

ipconfig /flushdns

Have a nice day.

Oracle has released VirtualBox 4.2 beta 1 today, which includes some major improvements, like improved Windows 8 support, an expert mode for wizards, experimental support for drag’n’drop from the host to Linux guests and more.
Changes in VirtualBox 4.2 beta 1:

  • Improved Windows 8 support, in particular many 3D-related fixes
  • GUI: VM groups
  • GUI: expert mode for wizards
  • GUI: allow to alter some settings during runtime
  • Support for up to 36 network cards, in combination with an ICH9 chipset configuration
  • Resource control: added support for limiting network IO bandwidth
  • Added possibility to start VMs during system boot on Linux, OS X and Solaris
  • Added experimental support for Drag’n’drop from the host to Linux guests. Support for more guests and for guest-to-host is planned.
  • Support recent VIA CPUs
  • Allow taking screenshots of the current VM window content
  • Allow automatically sorting of the VM list
  • Allow starting of headless VMs from the GUI
  • GUI: network operations manager
  • Improved VM context switch performance for Intel CPUs using nested paging
  • Added support for FlushByASID features of AMD CPUs (Bulldozer and newer)
  • Added readonly support for VHDX images, QED images and for QCOW (full support for v1 and readonly support for v2) images
  • Bug fixes

 

Since VirtualBox 4.2 is in beta, you will find bugs so don’t use this on a production machine! If you encounter bugs, report them on the VirtualBox Beta Feedback forum. For instance, in my test using Linux (Ubuntu) for both the guest and host machine, the new experimental drag’n’drop feature didn’t work for some reason – if you figure out how to get it to work, let us know in the comments!
For how to use some of the new features, like limiting network I/O bandwidth or staring a VM on system boot, see the VirtualBox manual, available via the download link below.

 

Download VirtualBox 4.2 beta 1 for Linux, Windows or Mac OS X

Update: VirtualBox 4.2.0 RC1 is now available for download @http://download.virtualbox.org/virtualbox/4.2.0_RC1/

Note: to be able to install VirtualBox 4.2 beta 1 in Ubuntu, you must firstly remove any installed VirtualBox version. For instance, if you have installed the latest stable VirtualBox 4.1, remove it using the following command:
sudo apt-get remove virtualbox-4.1
 

And then simply install the VirtualBox 4.2 beta 1 downloaded deb file.

 

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Skype v.4 released for linux Ubuntu based OS

Most important new features are:

  • Unified chat window (this can be disabled from the Chat options)
  • New Call View
  • Better call / video quality and new supported cameras

*** If you face this error during setup process :

 
Unpacking skype (from .../skype-ubuntu_4.0.0.7-1_i386.deb) ... 
dpkg: error processing Downloads/skype-ubuntu_4.0.0.7-1_i386.deb (--install): 
trying to overwrite '/etc/dbus-1/system.d/skype.conf', which is also in package skype-bin 2.2.0.35-0precise3 
dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)

***You have to run:


sudo apt-get purge skype 
sudo apt-get purge skype-bin 
sudo apt-get autoremove 

and then try to reinstall Skype. 🙂

Another fast way to download files and webpages in Mozilla Firefox is the download window of the browser.

You can quickly download files, webepages or other Urls by pressing

  ctrl+V  (for pc) or cmd + V (for mac)

in the Firefox download manager.