Cis GCP Cos 6.2.13

6.2.13 Ensure users' .netrc Files are not group or world accessible (Automated)

Description

While the system administrator can establish secure permissions for users' .netrc files, the users can easily override these.

Rationale

.netrc files may contain unencrypted passwords that may be used to attack other systems.

Audit Procedure

Run the following script and verify no results are returned:

#!/bin/bash

grep -E -v '^(root|halt|sync|shutdown)' /etc/passwd | awk -F: '($7 != "'"$(which nologin)"'" && $7 != "/bin/false") { print $1 " " $6 }' | while read user dir; do
  if [ ! -d "$dir" ]; then
    echo "The home directory ($dir) of user $user does not exist."
  else
    for file in $dir/.netrc; do
      if [ ! -h "$file" -a -f "$file" ]; then
        fileperm=$(ls -ld $file | cut -f1 -d" ")
        if [ $(echo $fileperm | cut -c5) != "-" ]; then
          echo "Group Read set on $file"
        fi
        if [ $(echo $fileperm | cut -c6) != "-" ]; then
          echo "Group Write set on $file"
        fi
        if [ $(echo $fileperm | cut -c7) != "-" ]; then
          echo "Group Execute set on $file"
        fi
        if [ $(echo $fileperm | cut -c8) != "-" ]; then
          echo "Other Read set on $file"
        fi
        if [ $(echo $fileperm | cut -c9) != "-" ]; then
          echo "Other Write set on $file"
        fi
        if [ $(echo $fileperm | cut -c10) != "-" ]; then
          echo "Other Execute set on $file"
        fi
      fi
    done
  fi
done

Expected Result

No results should be returned.

Remediation

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 user .netrc file permissions and determine the action to be taken in accordance with site policy.

Additional Information

While the complete removal of .netrc files is recommended if any are required on the system secure permissions must be applied.

On some distributions the /sbin/nologin should be replaced with /usr/sbin/nologin.

CIS Controls

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