About | Buy | Forum | Industry Watch | Learning Curve | Products | Search | Twitter | Xnews
Home » Learning Curve » Developers Workshop

Opening the iPhone

NerveGas has the spirit.


Buy It

Try It

NerveGas on #iphone figured out a clever way of enabling SSH on the iPhone.

It exploits Apple's 'generosity' in leaving things inside the (only) perimeter 'wide open'.

  1. First he overwrites the update binary with chmod.

  2. Then he tricks the iPhone into calling update so he can reset the mode of the Dropbear server to make it eXecutable.

  3. Then he puts everything back where it was.

Mission accomplished!

Working SSH Instructions by NerveGas

Previous instructions on the net have required the use of restore mode to set binary permissions. Unfortunately, restore mode doesn't work with all public versions of iPhoneInterface I've tried. The instructions below work by overwriting an existing binary on the system with chmod, and then calling it with the appropriate arguments to set permissions. The result is a fully functional SSH setup. You can then proceed to uploading your own world builds, or other programs to execute via commandline.

Step 1: Key creation.

On your Mac or PC download Dropbear from here:

    http://matt.ucc.asn.au/dropbear/dropbear.html

Run: ./configure && make

You don't need to install the software, just run:

    ./dropbearkey -t rsa -f dropbear_rsa_host_key
    ./dropbearkey -t dss -f dropbear_dss_host_key

And copy the two new key files into your iPhoneInterface directory.

Step 2: Uploading Dropbear and friends.

    Download the iphone-ssh kit and the iphone binaries kit:

        http://www.abigato.com/iphone-ssh-kit-vr1.tar.bz2
        http://netkas.freeflux.net/blog/

    Rename sh6 from the kit to sh.

    Use the jailbreak application to break out of jail and then open iPhoneInterface to connect.

    mkdir /etc/dropbear
    cd /etc/dropbear
    putfile dropbear_rsa_host_key
    putfile dropbear_dss_host_key
    cd /bin
    putfile chmod
    putfile sh
    cd /usr/bin
    putfile dropbear

Step 3: Overwriting 'update' with 'chmod'.

    While still connected to iPhoneInterface make a backup copy of /usr/sbin/update:

    cd /usr/sbin
    getfile update

    Rename this to update.original on your local filesystem

    Now copy the 'chmod' binary to 'update' and upload it back to the iPhone:

    cd /usr/sbin
    putfile update


Step 4: Overwriting the update configuration.

    Now the 'update' binary is really 'chmod' and has execute permissions! We
    just need to tell the iPhone to chmod next time it boots. To do this, we
    download /System/Library/LaunchDaemons/com.apple.update.plist and add our
    own arguments to ProgramArguments:

    0 /usr/sbin/update
    1 555
    2 /bin/chmod
    3 /bin/sh
    4 /usr/bin/dropbear

    Save the new plist and upload it back to the iPhone:

    cd /System/Library/LaunchDaemons
    putfile com.apple.update.plist

    While we're here, lets also:

    putfile au.asn.ucc.matt.dropbear.plist

Step 5: Reboot the iPhone twice.

    The first reboot should set the permissions on the dropbear and related
    binaries. The second reboot should start dropbear, so you can ssh to it:

    ssh -l root [IP ADDRESS]
    The root password is 'dottie'.


Step 6: Replace the original update and com.apple.update.plist files.

    Don't forget to put the old update files back. Rename update.original back
    to update, and delete the extra ProgramArguments you added to com.apple.update.plist.
    Now put them back:

    cd /System/Library/LaunchDaemons
    putfile com.apple.update.plist

    cd /usr/sbin
    putfile update

Step 7: Change the root password.

    If you don't like 'dottie', you can generate a new encrypted password by running:

    perl -e 'print crypt("MYPASSWORD", "XU");'

    Where MYPASSWORD is the new password you want, and XU is a random two-letter salt.
    Copy the encrypted output and replace the existing one in /etc/master.passwd on the phone.

You're done! Enjoy!
-NerveGas

See Also
Wooden Leg
Hacking the iPhone
'How I Hacked the iPhone'
iPhone
Alpine Dottie
Effective UID: 0
iPhone and Security
iPhone and the Media
iPhone Hack to be Patched
iPhone OS X System Architecture

Thanks to Devon at Pixel Groovy for the excellent artwork.

About | Buy | Forum | Industry Watch | Learning Curve | Products | Search | Twitter | Xnews
Copyright © Rixstep. All rights reserved.