LutelWall Unsafe Temporary File Lets Local Users Gain Elevated Privileges
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SecurityTracker Alert ID: 1014112
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SecurityTracker URL: http://securitytracker.com/id?1014112
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CVE Reference: CAN-2005-1879
(Links to External Site)
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Updated: Jun 9 2005
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Original Entry Date: Jun 6 2005
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Impact: Modification of system information, Modification of user information
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Version(s): 0.97 and prior versions
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Description: Eric Romang from ZATAZ Audit reported a vulnerability in LutelWall. A local user can gain elevated privileges.
The new_version_check() function creates a temporary file in an unsafe manner when updating to a new version. A local user can create
a symbolic link (symlink) from a critical file on the system to the temporary file used by the system. Then, when the target root
user runs the application to update the version, the symlinked file may be overwritten with the privileges of the target user.
The
vendor was notified on May 22, 2005, without response.
The original advisory is available at:
http://www.zataz.net/adviso/lutelwall-05222005.txt
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Impact: A local user can gain root privileges.
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Solution: No solution was available at the time of this entry.
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Vendor URL: firewall.lutel.pl/ (Links to External Site)
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Cause: Access control error, State error
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Underlying OS: Linux (Any)
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Reported By: ZATAZ Audits <exploits@zataz.net>
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Message History:
None.
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Source Message Contents
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Date: Mon, 06 Jun 2005 10:21:54 +0200
From: ZATAZ Audits <exploits@zataz.net>
Subject: LutelWall <= 0.97 insecure temporary file creation
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#########################################################
LutelWall insecure temporary file creation
Vendor: http://firewall.lutel.pl/index.php
Advisory: http://www.zataz.net/adviso/lutelwall-05222005.txt
Vendor informed: yes
Exploit available: yes
Impact : medium
Exploitation : low
#########################################################
The vulnerability is caused due to temporary file being created insecurely.
This can be exploited via symlink attacks to create and overwrite
arbitrary files
with the privileges of the user running the affected script.
The exploitation require that the root try to update the software.
##########
Versions:
##########
LutelWall <= 0.97
##########
Solution:
##########
non solution yet.
#########
Timeline:
#########
Discovered : 2005-05-22
Vendor notified : 2005-05-22
Vendor response : none
Vendor fix : no fix
Disclosure : 2005-06-06
#####################
Technical details :
#####################
Vulnerable code :
-----------------
# Prefix of temporary firewall files
tmp='/tmp/lutelwall'
new_version_check () { # Check for new version of script
if [ "`wget -V 2>&1 >/dev/null`" ]; then
message 3 "Warrning: Wget is required to check for updates."
else
new_ver=`wget -C off -O - -q -t 1 -T 3 -w 3 -U "\`uname -a 2>&1\`"
http://firewall.lutel.pl/ver`
if [ `echo $current_version | gawk '{ gsub("\\\.","") ; print 1$0 }'`
-lt `echo $new_ver | gawk '{ gsub("\\\.","") ; print 1$0 }'` ]; then
echo -e "\nThere is newer version of LutelWall (${new_ver})"
echo -n " Changes since previous version:"
echo `wget -C off -O $tmp-newfeat -q -t 1 -T 3 -w 3
http://firewall.lutel.pl/FEATURES-${new_ver}`
cat $tmp-newfeat
echo "Do you want to update [y/N]? "
read -s -t 5 -n 1 ln
if [ "$ln" = 'y' -o "$ln" = 'Y' ]; then
wget -O $tmp-script -q -T 3 http://firewall.lutel.pl/lutelwall
cat $tmp-script > $0
rm -rf $tmp-script
echo "Your firewall is up to date, exiting after update!"
exit
else
message 5 "Update aborted"
fi
else
message 5 "LutelWall is up-to-date"
fi;
fi;
}
#########
Related :
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nothing related
#####################
Credits :
#####################
Eric Romang (eromang@zataz.net - ZATAZ Audit)
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