Reboot Machines by Monitoring email Instructions

Purpose

To monitor for emails, then execute commands. In this case we want to

• Look for emails from users
• Verify the user sent the email
• Reboot their remote desktop
• Check for errors
• Report to the user the desktop is ready

For this run we want a Linux server to be the middle man to watch an inbox hosted on Office365, then tell Windows machines to reboot. If the Windows machine does not respond we want to use powercli to forcibly reboot using vsphere (and eventually KVM, which is ironically much easier to do. But when execs want to spend money on the main stream....)

Process

Here I am using Centos 7 with a basic install. Epel-release is installed as well.

Fetchmail

• Install fetchmail

yum -y install fetchmail

• Create a non-root user dedicated to the task

useradd mailuser
passwd mailuser
su mailuser
cd ~/

• Create .fetchmailrc and add the following contents

poll outlook.office365.com protocol imap port 993 username "user@login.tld" password "password" ssl sslfingerprint "97:08:33:5A:74:09:CC:EA:28:2D:9C:A4:49:3B:A2:C7"

• The fingerprint can be obtained using openssl

openssl s_client -connect outlook.office365.com:993 -showcerts | openssl x509 -fingerprint -noout -md5

• At this point you can run the following. If you created a new inbox your output should look similar

[emailuser@testserver ~]$ fetchmail -v --sslproto TLS1.2+ --sslcertck
fetchmail: 6.3.24 querying outlook.office365.com (protocol IMAP) at Tue 17 Apr 2018 02:29:42 PM EDT: poll started
Trying to connect to 40.97.100.50/993...connected.
fetchmail: Server certificate:
fetchmail: Issuer Organization: DigiCert Inc
fetchmail: Issuer CommonName: DigiCert Cloud Services CA-1
fetchmail: Subject CommonName: outlook.com
fetchmail: Subject Alternative Name: *.clo.footprintdns.com
fetchmail: Subject Alternative Name: *.nrb.footprintdns.com
fetchmail: Subject Alternative Name: *.hotmail.com
fetchmail: Subject Alternative Name: *.internal.outlook.com
fetchmail: Subject Alternative Name: *.live.com
fetchmail: Subject Alternative Name: *.office.com
fetchmail: Subject Alternative Name: *.office365.com
fetchmail: Subject Alternative Name: *.outlook.com
fetchmail: Subject Alternative Name: *.outlook.office365.com
fetchmail: Subject Alternative Name: attachment.outlook.live.net
fetchmail: Subject Alternative Name: attachment.outlook.office.net
fetchmail: Subject Alternative Name: attachment.outlook.officeppe.net
fetchmail: Subject Alternative Name: ccs.login.microsoftonline.com
fetchmail: Subject Alternative Name: ccs-sdf.login.microsoftonline.com
fetchmail: Subject Alternative Name: hotmail.com
fetchmail: Subject Alternative Name: mail.services.live.com
fetchmail: Subject Alternative Name: office365.com
fetchmail: Subject Alternative Name: outlook.com
fetchmail: Subject Alternative Name: outlook.office.com
fetchmail: Subject Alternative Name: substrate.office.com
fetchmail: Subject Alternative Name: substrate-sdf.office.com
fetchmail: outlook.office365.com key fingerprint: 97:08:33:5A:74:09:CC:EA:28:2D:9C:A4:49:3B:A2:C7
fetchmail: outlook.office365.com fingerprints match.
fetchmail: SSL/TLS: using protocol TLSv1.2, cipher ECDHE-RSA-AES256-GCM-SHA384, 256/256 secret/processed bits
fetchmail: IMAP< * OK The Microsoft Exchange IMAP4 service is ready. [QgBOADMAUABSADAAMwBDAEEAMAAxADAAOAAuAG4AYQBtAHAAcgBkADAAMwAuAHAAcgBvAGQALgBvAHUAdABsAG8AbwBrAC4AYwBvAG0A]
fetchmail: IMAP> A0001 CAPABILITY
fetchmail: IMAP< * CAPABILITY IMAP4 IMAP4rev1 AUTH=PLAIN AUTH=XOAUTH2 SASL-IR UIDPLUS MOVE ID UNSELECT CHILDREN IDLE NAMESPACE LITERAL+
fetchmail: IMAP< A0001 OK CAPABILITY completed.
fetchmail: IMAP> A0002 LOGIN "******@*******.com" *
fetchmail: IMAP< A0002 OK LOGIN completed.
fetchmail: IMAP> A0003 SELECT "INBOX"
fetchmail: IMAP< * 0 EXISTS
fetchmail: IMAP< * 0 RECENT
fetchmail: IMAP< * FLAGS (\Seen \Answered \Flagged \Deleted \Draft $MDNSent)
fetchmail: IMAP< * OK [PERMANENTFLAGS (\Seen \Answered \Flagged \Deleted \Draft $MDNSent)] Permanent flags
fetchmail: IMAP< * OK [UIDVALIDITY 14] UIDVALIDITY value
fetchmail: IMAP< * OK [UIDNEXT 4] The next unique identifier value
fetchmail: IMAP< A0003 OK [READ-WRITE] SELECT completed.
fetchmail: No mail for ******@*****.com at outlook.office365.com
fetchmail: IMAP> A0004 LOGOUT
fetchmail: IMAP< * BYE Microsoft Exchange Server IMAP4 server signing off.
fetchmail: IMAP< A0004 OK LOGOUT completed.
fetchmail: 6.3.24 querying outlook.office365.com (protocol IMAP) at Tue 17 Apr 2018 02:29:51 PM EDT: poll completed
fetchmail: normal termination, status 1

Parse Received Email

In this poor example I will be parsing the emails through a custom script. It would probably be better to do this using established tools.

Resolving user names from email

LDAP Search

• Install openldap client

yum -y install openldap-clients

Parsing directly from email

In this sample we want to pull the email address and subject from the email. At the moment this only works with a single email at a time for obvious reasons. Does not scale well.

#!/bin/bash
filetag1="/tmp/email_$(date +%s)"
filetag2="/tmp/parse_$(date +%s)"
filetag3="/tmp/address_$(date +%s)"
fetchmail -v --sslproto TLS1.2+ --sslcertck
if [ "$?" -ne "1" ] && [ "$?" -ne "0" ]; then
        /usr/bin/echo "$(date) : Failed to download emails" >> /home/email/fetch_log
else
    	/usr/bin/cp /var/mail/email $filetag1
        grep -E Subject:\|From: $filetag1 | sed 'N;s/\n/ /' > $filetag2
        :> /var/mail/email
        /usr/bin/rm -f $filetag1
        while read line; do
        user=$(grep -Ei Subject:\ [a-z]+,[a-z].[a-z]+ <<<$line | awk 'BEGIN {FS=","} {print $2}')
        from1=$(grep -Eo "From:.*[a-zA-Z_'-']+@[a-zA-Z_'-']+.com>" <<<$line | sed -e 's/From:\ [A-Za-z]\+\ [A-Za-z]\+\ <//g; s/>//g')
        if grep -qiE domain1.tld\|domain2.tld\|domain3.tld <<< $from1 ; then

               /home/mailuser/restartdesktop.sh $user &
        fi
        done < $filetag2
        /usr/bin/rm $filetag2
fi

Restarting Machines

Restart Windows Machines Using Native Tools

• Install samba-common-tools

yum -y install samba-common-tools

• A command like the following will work

net rpc shutdown -r -W <domain> -S <hostname> --user <username>