Vulnerability Discussion

Extended attributes in file systems are used to contain arbitrary data and file metadata with security implications.

Check

Verify the file integrity tool is configured to verify extended attributes.

Check to see if Advanced Intrusion Detection Environment (AIDE) is installed on the system with the following command:

# yum list installed aide

If AIDE is not installed, ask the System Administrator how file integrity checks are performed on the system.

If there is no application installed to perform file integrity checks, this is a finding.

Note: AIDE is highly configurable at install time. These commands assume the "aide.conf" file is under the "/etc" directory.

Use the following command to determine if the file is in another location:

# find / -name aide.conf

Check the "aide.conf" file to determine if the "xattrs" rule has been added to the rule list being applied to the files and directories selection lists.

An example rule that includes the "xattrs" rule follows:

All= p+i+n+u+g+s+m+S+sha512+acl+xattrs+selinux
/bin All # apply the custom rule to the files in bin
/sbin All # apply the same custom rule to the files in sbin

If the "xattrs" rule is not being used on all uncommented selection lines in the "/etc/aide.conf" file, or extended attributes are not being checked by another file integrity tool, this is a finding.

Fix

Configure the file integrity tool to check file and directory extended attributes.

If AIDE is installed, ensure the "xattrs" rule is present on all uncommented file and directory selection lists.