PAM configuration for sending email alerts for ssh logins

ssh-login-email-alert.md

Receive an email alert for each ssh login. The script can be extended to support other notification methods such as Slack, etc.

mkdir -p /etc/pam.scripts
chmod 0755 /etc/pam.scripts
vim /etc/pam.scripts/ssh_alert.sh

add the following script to ssh_alert.sh, modifying the variables from their default value

#!/bin/bash

# Your Email Information: Recipient (To:), Subject and Body
RECIPIENT="test@example.com"
SUBJECT="SSH Login on example.com"

# enable IP whitelisting by setting to 'true'. doesn't alert if the ip address is contained within the whitelist
WHITELIST_ENABLED="true"

if [[ "$WHITELIST_ENABLED" == "true" ]]; then
	# use this regex to whitelist any IP addresses you want to ignore. 
    if [[ "$PAM_RHOST" =~ ^(1.1.1.1)$ ]]; then
        exit 0
    fi
fi

BODY="
A SSH login was successful, so here are some information for security:
  	User:        $PAM_USER
	User IP Host: $PAM_RHOST
	Service:     $PAM_SERVICE
	TTY:         $PAM_TTY
	Date:        `date`
	Server:      `uname -a`
"

if [[ "${PAM_TYPE}" = "open_session" ]]; then
	echo "${BODY}" | mail -s "${SUBJECT}" ${RECIPIENT}
fi

exit 0

set the permissions on the script chmod 0700 /etc/pam.scripts/ssh_alert.sh

add the script to the PAM configuration vim /etc/pam.d/sshd

# SSH Alert script
session optional pam_exec.so /etc/pam.scripts/ssh_alert.sh

ssh-login-pushover.md

Receive a pushover notification for each ssh login.

mkdir -p /etc/pam.scripts
chmod 0755 /etc/pam.scripts
vim /etc/pam.scripts/ssh_alert.sh

add the following script to ssh_alert.sh, modifying the variables from their default value

#!/bin/bash

# enable IP whitelisting by setting to 'true'. doesn't alert if the ip address is contained within the whitelist
WHITELIST_ENABLED="true"

if [[ "$WHITELIST_ENABLED" == "true" ]]; then
	# use this regex to whitelist any IP addresses you want to ignore. 
    if [[ "$PAM_RHOST" =~ ^(1.1.1.1)$ ]]; then
        exit 0
    fi
fi

if [[ "${PAM_TYPE}" = "open_session" ]]; then
	curl -s \
    --form-string "token=APP_TOKEN" \
    --form-string "user=USER_KEY" \
    --form-string "message=SSH login for $PAM_USER on $HOSTNAME from $PAM_RHOST" \
    https://api.pushover.net/1/messages.json
fi

exit 0

set the permissions on the script chmod 0700 /etc/pam.scripts/ssh_alert.sh

add the script to the PAM configuration vim /etc/pam.d/sshd

# SSH Alert script
session optional pam_exec.so /etc/pam.scripts/ssh_alert.sh