Cis Ubuntu1204 V110 13 7

13.7 Check Permissions on User Home Directories (Scored)

Profile Applicability

• Level 1

Description

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

Rationale

Group or world-writable user home directories may enable malicious users to steal or modify other users' data or to gain another user's system privileges.

Audit Procedure

Using Command Line

#!/bin/bash
for dir in `/bin/cat /etc/passwd  | /bin/egrep -v '(root|halt|sync|shutdown)' | /usr/bin/awk -F: '($7 != "/usr/sbin/nologin") { print $6 }'`; do if
[ -d $dir ]; then
        dirperm=`/bin/ls -ld $dir | /usr/bin/cut -f1 -d" "`
if [ `echo $dirperm | /usr/bin/cut -c6 ` != "-" ]; then
echo "Group Write permission set on directory $dir"           fi
        if [ `echo $dirperm | /usr/bin/cut -c8 ` != "-" ]; then
echo "Other Read permission set on directory $dir"            fi
        if [ `echo $dirperm | /usr/bin/cut -c9 ` != "-" ]; then
echo "Other Write permission set on directory $dir"           fi
        if [ `echo $dirperm | /usr/bin/cut -c10 ` != "-" ]; then
echo "Other Execute permission set on directory $dir"         fi
fi done

Expected Result

No output should be returned. Any output indicates home directories with overly permissive settings.

Remediation

Using Command Line

Making global modifications to user home directories 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 file permissions and determine the action to be taken in accordance with site policy.

Default Value

Default home directory permissions are typically set to 755 (drwxr-xr-x) when created with useradd.

References

• CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0

Profile

Level 1 - Scored