bug#49260: Vulnerability Report [Misconfigured DMARC Record Flag]

[Cyber Zeus]

Hi Team,
I am an independent security researcher and I have found a bug in your website  
The details of it are as follows:-

Description: This report is about a misconfigured Dmarc/SPF record flag, which can be used for malicious purposes as it allows for fake mailing on behalf of respected organizations.

About the Issue:
As i have seen the DMARC record for 

gnu.org

which is:

DMARC Policy Not Enabled

DMARC Not Found

   
As u can see that you Weak SPF record, a valid record should be like:-

DMARC Policy Enabled
What's the issue:
An SPF/DMARC record is a type of Domain Name Service (DNS) record that identifies which mail servers are permitted to send an email on behalf of your domain. The purpose of an SPF/DMARC record is to prevent spammers from sending messages on the behalf of your organization.

Attack Scenario: An attacker will send phishing mail or anything malicious mail to the victim via mail: 

bug-gnuzilla@gnu.org

even if the victim is aware of a phishing attack, he will check the origin email which came from your genuine mail id 

bug-gnuzilla@gnu.org

so he will think that it is genuine mail and get trapped by the attacker.
The attack can be done using any PHP mailer tool like this:-

<?php
$to = "VICTIM@example.com";
$subject = "Password Change";
$txt = "Change your password by visiting here - [VIRUS LINK HERE]l";
$headers = "From: 

bug-gnuzilla@gnu.org

";mail($to,$subject,$txt,$headers);
?>

U can also check your Dmarc/ SPF record form: MXTOOLBOX

Reference:
https://support.google.com/a/answer/2466580?hl=en
have a look at the GOOGLE article for a better understanding!