The first thing we will do is create a table in your database called "Users" with the following fields:

We will be creating 3 pages:
▪ loginCFC.cfc
▪ login.cfm
▪ logout.cfm

The first page that we will create is "loginCFC.cfc". 
<cfcomponent name="LoginCFC">
    <cfscript>
        // call our internal initialize function
        init();
    </cfscript>

    <cffunction name="init" access="public">
        <!--- initialize data for component --->
        <cfparam name="request.dsn" default="loginCFC">
    </cffunction>

    <cffunction access="public" name="verifyUser">
        <!--- make sure username and password are required --->
        <cfargument name="getUsername" type="string" required="yes">
        <cfargument name="getPassword" type="string" required="yes">

        <!--- query the database for the username and password that were passed --->
        <cfquery name="verifyusername" datasource="#request.dsn#">
            SELECT username
            FROM Users
            WHERE username = '#arguments.getUsername#' 
            AND password = '#arguments.getPassword#'
        </cfquery>

        <!--- return the result --->
        <cfif verifyusername.recordCount>
            <cfreturn verifyusername.username>
        <cfelse>
            <cfreturn False>
        </cfif>
    </cffunction>
</cfcomponent>

Next we will create the ?login.cfm? page
<!--- Make sure form was submitted --->
<cfif structKeyExists(form,"verify")>
    <cfinvoke component="loginCFC" 
                   method="verifyUser"
                   returnVariable="verify"
                   getUsername="#form.username#"
                   getPassword="#form.password#">
</cfif>

<!--- Login Form --->
<cfform name="security" method="post" action="">
    Username: <cfinput name="username" type="Text"><br>
    Password:<cfinput name="password" type="password"><br>
    <cfinput type="Submit" name="verify">
</cfform>

<!--- If login was successful tell user that the username and password were verified successfully. If not, tell the user their username and/or password was wrong --->
<cfif isDefined("variables.verify")>
    <cfif variables.verify NEQ 0>
        Verified Successfully!
    <cfelse>
        Incorrect Username and/or Password!
    </cfif>
</cfif>

Finally we will create the ?logout.cfm? page
<cfscript>
    StructClear(variables);
</cfscript>

<cflocation url="login.cfm" addtoken="No">