Ensure PAM Displays Last Logon/Access Notification
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Description
To configure the system to notify users of last logon/access using pam_lastlog,
add or correct the pam_lastlog settings in /etc/pam.d/login
to include showfailed option, such as:
session required pam_lastlog.so showfailed
And make sure that the silent option is not set for this specific line.
Rationale
Users need to be aware of activity that occurs regarding their account. Providing users with
information regarding the number of unsuccessful attempts that were made to login to their
account allows the user to determine if any unauthorized activity has occurred and gives them
an opportunity to notify administrators.
Shell script
The following script can be run on the host to remediate the issue.
#!/bin/bash
# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; then
if [ -f /usr/bin/authselect ]; then
if authselect list-features minimal | grep -q with-silent-lastlog; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
authselect disable-feature with-silent-lastlog
authselect apply-changes -b
else
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/login")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
if [ -e "$PAM_FILE_PATH" ] ; then
PAM_FILE_PATH="$PAM_FILE_PATH"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if ! grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*session\s+.*\s+pam_lastlog.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*session\s+).*(\bpam_lastlog.so.*)/\1'"required"' \2/' "$PAM_FILE_PATH"
else
LAST_MATCH_LINE=$(grep -nP "^\s*session.*include\s+common-session$" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
if [ ! -z $LAST_MATCH_LINE ]; then
sed -i --follow-symlinks $LAST_MATCH_LINE' a session '"required"' pam_lastlog.so' "$PAM_FILE_PATH"
else
echo 'session '"required"' pam_lastlog.so' >> "$PAM_FILE_PATH"
fi
fi
fi
# Check the option
if ! grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s*.*\sshowfailed\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks '/\s*session\s+'"required"'\s+pam_lastlog.so.*/ s/$/ showfailed/' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "$PAM_FILE_PATH was not found" >&2
fi
if [ -e "$PAM_FILE_PATH" ] ; then
PAM_FILE_PATH="$PAM_FILE_PATH"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s.*\bsilent\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*session.*'"required"'.*pam_lastlog.so.*)\ssilent=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "$PAM_FILE_PATH was not found" >&2
fi
fi
else
if [ -e "/etc/pam.d/login" ] ; then
PAM_FILE_PATH="/etc/pam.d/login"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/login")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if ! grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*session\s+.*\s+pam_lastlog.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*session\s+).*(\bpam_lastlog.so.*)/\1'"required"' \2/' "$PAM_FILE_PATH"
else
LAST_MATCH_LINE=$(grep -nP "^\s*session.*include\s+common-session$" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
if [ ! -z $LAST_MATCH_LINE ]; then
sed -i --follow-symlinks $LAST_MATCH_LINE' a session '"required"' pam_lastlog.so' "$PAM_FILE_PATH"
else
echo 'session '"required"' pam_lastlog.so' >> "$PAM_FILE_PATH"
fi
fi
fi
# Check the option
if ! grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s*.*\sshowfailed\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks '/\s*session\s+'"required"'\s+pam_lastlog.so.*/ s/$/ showfailed/' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/login was not found" >&2
fi
if [ -e "/etc/pam.d/login" ] ; then
PAM_FILE_PATH="/etc/pam.d/login"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/login")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s.*\bsilent\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*session.*'"required"'.*pam_lastlog.so.*)\ssilent=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/login was not found" >&2
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Warning
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
