Tools for Red Star OS (붉은별)

This repository includes several binaries from and tools for Red Star OS. These can be used for further research work.

Disable malicious components

The easiest way is to run the defuse.sh script on Red Star OS 3.0 Desktop (requires root privileges).

Manual steps

1. Get root privileges via /usr/sbin/rootsetting

2. Disable SELinux

   SELinux protects several files an directories (e.g. /var/log). It should be disabled in order to make changes to some parts of the system.

    setenforce 0
   

   In order to keep SELinux disabled after rebooting, append selinux=0 to the kernel line in the GRUB config file (/boot/grub/grub.conf).

3. Kill securityd

   Killing securityd will prevent the system from rebooting when editing/deleting various protected files.

    killall -9 securityd
   

4. Disable rtscan kernel module

   Either via resctl.py (see rtscan) or via a Python shell as follows:

    [root@localhost ~]# python
    Python 2.6 (r26:66714, Oct  7 2012, 13:39:47)
    [GCC 4.4.0 20090506 (Red Hat 4.4.0-4)] on linux2
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import fcntl
    >>> fcntl.ioctl(open('/dev/res', 'wb'), 29187)
    0
   

   After disabling rtscan protected processes like opprc will become killable.

5. Kill scnprc and opprc

    killall scnprc
    killall opprc
   

6. Replace /usr/lib/libos.so.0.0.0

   See libos for further information. Replacing this file will prevent the system from rebooting via securityd after rebooting the system. It also will prevent reboot loops by kdm rendering the system unusable.

7. Delete /usr/share/autostart/scnprc.desktop

   Deleting this file will prevent kdeinit from starting the framework after a system reboot.

8. Delete /etc/init/ctguard.conf

   Deleting this file will prevent init from starting opprc even when scnprc is not running.

9. Reboot the system

Debugging

Prepare building environment

The default installation of Red Star OS 3.0 Desktop does not include GCC but the ISO includes the required packages.

1. Insert the Red Star OS ISO into the system

2. Go to /media/RedStar\ Desktop\ 3.0/RedStar/RPMS

3. Install the following packages:

    yum localinstall glibc-headers-2.10.1-2.i386.rpm
    yum localinstall glibc-devel-2.10.1-2.i386.rpm
    yum localinstall ncurses-devel-5.6-0.rs3.0.i386.rpm
    yum localinstall gcc-4.4.0-4.i386.rpm
   

Now it is possible to build a recent (e.g. the latest) version of GDB for better debugging.

Install non-stripped threading libraries

The default installation of Red Star OS 3.0 Desktop does not allow to debug threads with the shipped version of GDB in e.g. scnprc and opprc because the required libpthread.so.0 library is stripped.

Use the libpthread-2.10.1.so/libpthread.so.0 and libthread_db-1.0.so/libthread_db.so.1 libraries from the glibc-2.10.1-2.i686.rpm package of Fedora 11.

Disclaimer

All of the information is based on research dedicated to analyzing Red Star OS. The authors take no responsibility for the accuracy, completeness or quality of the information provided.