5.3.10 Ensure System Accounts cannot access system using ftp.

Information

If ftp is active on the system, the file /etc/ftpusers is a deny list used by ftp daemon containing a list of users who are not allowed to access the system via ftp

The /etc/ftpusers file contains a list of users who are not allowed to access the system via ftp All users with a UID less than 200 should typically be added into the file.

Solution

List all users with a UID less than 200 to the /etc/ftpusers file:

lsuser -c ALL | grep -v ^#name |grep -v root | cut -f1 -d: | while read NAME; do
if [ `lsuser -f $NAME | grep id | cut -f2 -d=` -lt 200 ] > /dev/null 2>&1; then
echo "Would add $NAME to /etc/ftpusers"
fi
done

NOTE: Review the list of users

Add all relevant users with a UID of less that 200 to the /etc/ftpusers file:

lsuser -c ALL | grep -v ^#name |grep -v root | cut -f1 -d: | while read NAME; do
if [ `lsuser -f $NAME | grep id | cut -f2 -d=` -lt 200 ] > /dev/null 2>&1; then
echo $NAME >> /etc/ftpusers
fi
done

See Also

https://workbench.cisecurity.org/benchmarks/10385

Item Details

Category: IDENTIFICATION AND AUTHENTICATION

References: 800-53|IA-5

Plugin: Unix

Control ID: 2056763fed7357ee1528555051a226b8b10a46d980e14441ad5db143b24ca919