QPopper

This how to explains how to setup qpopper (pop3) with ssl encryption to securely download emails from your pop3. (JT:I used 1b)

This howto strictly depends on you having a base knowledge of qpopper and OpenSSL in general, it does not guide the install of either, only the setup between the two. But lets be sure you've compiled qpopper with ssl support? ;)

First create a place to store your openssl keys safely

mkdir -p -m665 /etc/mail/certs
chown root:mail /etc/mail/certs
chmod 660 /etc/mail/certs

Use openssl to create a public-private key pair and a certificate signing request (csa).

                                         
openssl req -new -nodes -out req.pem -keyout /etc/mail/certs/cert.pem

(follow questions it asks after this command is used and fill the options in completely)

next,

chmod 600 /etc/mail/certs/cert.pem
chown root:0 /etc/mail/certs/cert.pem

if you dont want to send your cert in, to pay for a real CA to sign it do NOT do this step right now follow 1b. below this 1a.

1a. send the certificate signing request (file req.pem) to your Certificate Authority for signing. You will receive back a signed request. Assuming this signed request is in a file called signed_req.pem, concatenate it to the private key generated earlier:

cat signed-req.pem >> /etc/mail/certs/cert.pem

1b. if you want to sign your own and be your own CA from above to avoid sending it to a Certificate Authority do the following. AFTER you have done the above up to the cat signed-req, which will be done the following 3.

openssl genrsa -des3 -out ca.key 1024
openssl req -new -x509 -days 365 -key ca.key -out ca.crt
openssl x509 -req -CA ca.crt -CAkey ca.key -days 365 -in req.pem -out
signed-req.pem -CAcreateserial

now you can

cat signed-req.pem >> /etc/mail/certs/cert.pem

--

next we configure /etc/qpopper.conf , you may place this anywhere you like in your system inside of it there are a few options to adjust inside. they are as follows. (set tls-support) can also be "stls".

set tls-support              = alternate-port
set tls-version              = default
set tls-server-cert-file     = /etc/mail/certs/cert.pem

to wrap things up

Use the -f config-file-path command-line option to tell Qpopper to read the configuration file. a sample inetd line is below:

pop3s           stream  tcp     nowait  root    /usr/sbin/tcpd  /usr/sbin/in.qpopper -f /etc/qpopper.conf

(of course making sure pop3s is inside of your /etc/services as --> pop3s 995/tcp

if using inetd, killall -HUP inetd, and you should be all set.

taken from http://www.defcon1.org/html/Security/Qpop-SSL/qpop-ssl.html