The ftpusers file must not have an extended ACL.

From Oracle Linux 5 Security Technical Implementation Guide

Associated with: CCI-000225

SV-63083r1_rule The ftpusers file must not have an extended ACL.

Vulnerability discussion

Excessive permissions on the ftpusers file could permit unauthorized modification. Unauthorized modification could result in Denial of Service to authorized FTP users or permit unauthorized users to access the FTP service.

Check content

Check the permissions of the /etc/ftpusers file. # ls -lL /etc/ftpusers /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers If the permissions include a '+', the file has an extended ACL. If the file has an extended ACL and it has not been documented with the IAO, this is a finding.

Fix text

Remove the extended ACL from the file. # setfacl --remove-all /etc/ftpusers /etc/vsftpd.ftpusers /etc/vsftpd/ftpusers

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.