6.2.15 Ensure no users have .netrc files

Information

Thenetrc file contains data for logging into a remote host for file transfers via FTP.

Thenetrc file presents a significant security risk since it stores passwords in unencrypted form. Even if FTP is disabled, user accounts may have brought overnetrc files from other systems which could pose a risk to those systems.

Solution

Making global modifications to users' files without alerting the user community can result in unexpected outages and unhappy users. Therefore, it is recommended that a monitoring policy be established to report usernetrc files and determine the action to be taken in accordance with site policy.

The following script will remove .netrc files from interactive users' home directories

#!/bin/bash

awk -F: '($1!~/(halt|sync|shutdown|nfsnobody)/ && $7!~/^(/usr)?/sbin/nologin(/)?$/ && $7!~/(/usr)?/bin/false(/)?$/) { print $6 }' /etc/passwd | while read -r dir; do
if [ -d "$dir" ]; then
file="$dir/.netrc"
[ ! -h "$file" ] && [ -f "$file" ] && rm -f "$file"
fi
done

See Also

https://workbench.cisecurity.org/files/3796

Item Details

Category: CONFIGURATION MANAGEMENT, SYSTEM AND SERVICES ACQUISITION

References: 800-53|CM-2, 800-53|CM-6, 800-53|CM-7, 800-53|CM-7(1), 800-53|CM-9, 800-53|SA-3, 800-53|SA-8, 800-53|SA-10, CSCv7|16.4

Plugin: Unix

Control ID: fd69898899e36d0190dcc1ca693e22f0d71f6f3b102fbbfefb10a447fe57813e