CIS Ubuntu 14.04 LTS - 6.2.13 Ensure users' .netrc Files are not group or world accessible

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

Profile Applicability

• Level 1 - Server
• Level 1 - Workstation

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

cat /etc/passwd | egrep -v '^(root|halt|sync|shutdown)' | awk -F: '($7 != "/sbin/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 output 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.

Default Value

Not applicable.

Notes

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.

References

None

CIS Controls

14.4 Protect Information With Access Control Lists - All information stored on systems shall be protected with file system, network share, claims, application, or database specific access control lists.

Profile

• Level 1