Security issue reporting guidelines

If you think you have found a security vulnerability in FastMail, please report it to us straight away by emailing bugreport@fastmail.com. Please include detailed steps to reproduce and a brief description of what the impact is. We encourage responsible disclosure (as described below), and we promise to investigate all legitimate reports in a timely manner and fix any issues as soon as we can.

We aim to respond to all emails within 24 hours, although fixing the problem may often take longer. If you don't receive some response to your email with 24 hours, then it's possible a spam filter or other issue has delayed the email. Please try emailing us again from a different account or location.

Responsible disclosure policy

We ask that during your research you make every effort to maintain the integrity of our users' data, avoiding violating privacy or degrading our service. You must give us reasonable time to fix any vulnerability you find before you make it public. In return we promise to investigate reports promptly and not to take any legal action against you.

Bug bounty

As a measure of our appreciation for security researchers, we are happy to give full credit in our public postmortem after the bug has been fixed, and we offer a monetary bounty for certain qualifying bugs. To qualify for the bounty, you must:

• Follow our responsible disclosure policy (see above).
• Report the bug to us first, and give us reasonable time to fix the issue before making it public.
• Be the first person to report the issue to us.
• Use a test account (a free trial account is fine), or an account that you control. Never interact with other accounts without the owner's consent.
• Find a bug that could allow access to private user data, or enable access to a system running FastMail infrastructure.

Examples of valid vulnerability types include:

• Authentication or session management issues
• Cross-Site Scripting (XSS) (only on www.fastmail.com or beta.fastmail.com, not on user.fm or fastmailusercontent.com; see below)
• Cross-Site Request Forgery (CSRF/XSRF)
• Remote Code Execution
• Privilege Escalation

The decision of whether a bug qualifies for a bounty is solely at the discretion of FastMail. Any qualifying bug will be eligible for a bounty of a minimum of US $100 and a maximum of $5,000. The exact value will be determined by FastMail after taking into account the severity of the vulnerability, the number of users potentially affected etc. All bounties will be paid via PayPal. Any taxes or fees are the sole liability of the recipient.

Specific exclusions

People seem to report these regularly, so we're putting them up front to make it clear we do not regard these as bugs

1. Email spoofing bugs do not qualify. We are quite aware that users can set arbitrary From addresses on emails, that our SPF records allow arbitrary hosts to send email as our domains, and that we don't yet have a DMARC policy. These policy decisions are by design, and we track the actual sender in a separate header.
2. CSV Excel Macro Injection bugs via address book exporting do not qualify. The user has complete control over their address book. We regard convincing someone to add a particular address to their address book, export and download it as a CSV, open it in Excel, click through a warning dialog as exceedingly unlikely user interaction. If you can get them to do that, just get them to run cmd from the Start menu and paste some arbitrary command.

General Exclusions

1. Denial of Service (DOS) and social engineering attacks do not qualify and must not be attempted against FastMail or our users under any circumstances.
2. Bugs that require exceedingly unlikely user interaction or are caused by insecurities in browser extensions do not qualify.
3. Brute force log in attempts.
4. The domains user.fm and fastmailusercontent.com are used to host potentially unsafe user content. By keeping this content in completely separate domains, we avoid any security issues with our core fastmail.com domain. As such, any Cross-Site Scripting (XSS) attacks on these sites are not of interest to us. Please note that if you go to a user web site such as http://testuser.fastmail.com it immediately redirects to http://testuser.fastmail.com.user.fm and is thus in the user.fm security domain, not the fastmail.com domain.
5. Bugs on sites associated with FastMail but not run by FastMail do not qualify. This includes www.fastmailfbl.com. We are grateful for any reports on issues with these sites, and we will pass on the bugs to the relevant company, however they do not qualify for a bounty.
6. Anything related to enumeration of usernames does not qualify.
7. Bugs related to unpatched, out of date or exceedingly rarely used browsers or other client software out of our control.
8. We are public about the software we run. We are not interested in reports about "leakage" of the fact we run nginx, or the version number, or Perl module names or file paths.

Hall of fame

Our thanks to the following security researchers for their submissions:

Researcher	Vulnerability found	Bounty paid
Max Justicz	Write access to server files	$4000
Sergey Markov	Read-only access to private server files	$2000
Thomas Guittonneau	Read-only access to private server files	$2000
Arsiadi Sriyanto	Reflected XSS	$1500
Salman Niksefat	XSS in email body (classic interface or old browsers only)	$1500
Sergey Markov	HTTP header injection	$1000
Frans Rosén	XSS in email (classic interface only)	$1000
Prashant Sharma	Stored XSS in our support ticket system	$1000
Hammad Shamsi	Stored XSS in our support ticket system	$1000
Bastian Welfrid Purba	Missing user privilege check for removing user websites	$1000
Arsiadi Sriyanto	Read access to private file storage metadata	$500
Bogdan Calin	HTTP header injection	$500
Shiv Bihari Pandey	Security settings unlock bypass	$500
John Cleary	Incorrect CalDAV ACL check allowed access to list of unrelated users	$500
Lucas Reddinger	Missing “enabled” check for shared calendar link	$500
Richard Smith	2FA bypass when importing a user into a business	$300
Bastian Welfrid Purba	CSRF in support ticket creation	$250
Bastian Welfrid Purba	Missing user privilege check for fetching saved searches	$250
Arsiadi Sriyanto	XSS on DAV subdomains	$200
Satish Bommisetty	Can trick user into making phone call in iOS app	$200
Bastian Welfrid Purba	4 self-XSS issues (not exploitable)	$400
Shiv Bihari Pandey	SMS verification bypass	$250
V. Harish Kumar	2 self-XSS issues (not exploitable)	$200
n00b 4lw4y5 7ry	Open redirect	$100
James Kettle (PortSwigger Web Security)	Login CSRF	$100
Ranjeet Singh	IMAP connections not immediately killed on password change	$100
Sasi Levi	Self-XSS issue (not exploitable)	$100
Manikandan Rajakumar	Self-XSS issue (not exploitable)	$100
Lyon Yang	XSS in embedded image in email body (only classic interface, only IE6, only if remote images enabled)	$100
Jakub Zoczek	HTTP header injection (only on redirect)	$100
Rakesh Mane	Self-XSS issue (not exploitable)	$100
Sasi Levi	CSRF on some business/family account admin actions	$100
Sasi Levi	CSRF on some folder sharing actions	$100
Hammad Shamsi	Open redirect in paypal handler	$100
Hugh Davenport	Deletion of contacts/events with restricted logins	$100
Mike Cardwell	Image proxying bypass on reply	$100
Hugh Davenport	window.opener phishing vulnerabilty in classic interface	$100
Anonymous	window.opener phishing vulnerabilty	$100