Thursday, November 05, 2015

How to Disable System Integrity Protection(SIP) or rootless mode in OS X El Capitan.

System Integrity Protection or Rootless mode is a security feature of OS X El Capitan operating system  by Apple Inc. It protects certain system processes, file and folders from being modified or tampered with by other processes even when executed by the root user or by a user with root privileges(sudo). Following are the the key concepts of System Integrity Protection.

1. System Locations Cannot Be Written To  -  System files can be modified only by system processes signed with Apple’s code signing identity. App processes should instead write to locations designated for third-party developers.

The following directories can only be written to by the system: 

System-Only Locations 

    ● /bin 
    ● /sbin 
    ● /usr 
    ● /System 

In contrast, the following directories are available to any process: 

Locations Available to Developers 
    ● /usr/local 
    ● /Applications 
    ● [~]/Library 

All directories in /usr except for /usr/local are restricted to the system. Apple app directories in /Applications are restricted to the system.

2. System Processes Cannot Be Attached To  - System binaries can be modified only by Apple Installer and Software Update from Apple-provided packages, and no longer permit runtime attachment or code injection.

3. Kernel Extensions Must Be Signed - Kernel extensions must be signed with a Developer ID for Signing Kexts certificate.

Security configuration is stored in NVRAM rather than in the file system itself. As a result, this configuration applies to all installations of OS X across the entire machine and persists across OS X installations that support System Integrity Protection.

System Integrity Protection can be configured using the csrutil(1) command.

The following command will check the status of the SIP on the system.

$ csrutil status 
System Integrity Protection status: enabled.

To enable or disable System Integrity Protection, you must boot to Recovery partition and run the csrutil  command from the Terminal. 

       1. Boot to Recovery OS by restarting your machine and holding down the Command and R keys at startup. 
       2. Launch Terminal from the Utilities menu. 
       3. Enter the following command: 
              $ csrutil disable 
       Note:  After enabling or disabling System Integrity Protection on a machine, a reboot is required.

For more information on SIP, click here

How to change the default font in Outlook for Mac 2016 on OS X.

It very easy to change the font style in outlook for Mac 2016 on OS X. Follow below steps to change the default font.

  1. Open "Outlook"  application on Mac.
  2. Open Preferences of Outlook 
     3. Click on Fonts to change the default font settings for the outlook.
     4. Select the desired font to set as default font.

     5. Close the preferences window.
     6. Click on New Email, Now your default font would set to the newly configured font style.

Tuesday, October 20, 2015

plutil - a very usefull command line tool on mac to edit encoded plist files

plutil - is a very useful tool to decode and encode the plist files on OSX system. The tool can be used decode the plist file to human readable format in Terminal which would help user to edit the plist files in terminal using vim or nano etc.

plutil -convert xml1 [path_to_the_plist_file]

The above command will decode the plist file to a readable xml format in command line.

plutil -convert binary1 [path_to_the_plist_file]

The above command can be used encode back the file to original binary format from command line.

How to add tab completion in Apple OS X

Tab completion in Linux is a very useful feature. On OS X the tab completion can be enabled as well. The tab completion can be enabled on OS X by adding few lines to .inputrc file.

  1. Open
  2. Go to your home directory such as  /Users/user.
  3. Open vim to create .inputrc file in home directory by running following command.
    • vim .inputrc
  4. Add following lines to the file
    • set completion-ignore-case on
    • set show-all-if-ambiguous on
    • TAB: menu-complete
  5. Save the file using "esc + :wq" in vim.
  6. Now open another tab to see the changes to tab completion in bash shell.

Tuesday, September 01, 2015

Why and how we can bypass restricted paid WiFi's at public places such as airports, etc ?

            We might be wondering some times on how to bypass the restricted paid wifi in public places to access particular URL . To bypass some poorly configured WiFi's just append (without the double quotes)   " ?.jpg  " to end of your URL string. This should work in many instances where generally blocker is configured let images through.  Appending ?.jpg to the URL makes the blocker think that the URL is an image. On the other hand, anything after the ? doesn't change the actual webpage requested, it only changes the GET headers. (so and give the same page). Note that if there already is a query string in the URL (something after a question mark), then you must use &.jpg instead of ?.jpg, as only the first question mark is considered for making a query string