Major Vulnerability in Freshdesk – Results from a recent Wordfence Red Team Exercise

Wordfence recently conducted a red team exercise on our own network. That means that two of my team members secretly conducted a simulated attack on our network and a passive attack on our SaaS providers. We were careful in limiting the scope of this attack, and so our attack on external providers was limited to passive activity like source code analysis and passive analysis of web services.

We turned up several items during the red team exercise that helped make our systems and services more secure. Sean Murphy, the lead on this exercise made a startling discovery during the exercise: Freshdesk, our customer service portal provider, had a single sign-on (SSO) implementation that allowed a user to create an account in the support system with ordinary privileges and then promote themselves to administrator level.

This security hole did not just affect Wordfence. It also affected any Freshdesk customer using simple SSO. Customers using SAML SSO were not affected by this issue.

The SSO vulnerability we discovered in Freshdesk affects Freshdesk customers using single sign-on via their WordPress plugin and any other integration that uses their simple SSO mechanism – so it goes beyond just WordPress SSO integration with Freshdesk.

Freshdesk has over 70,000 customers and their customers include many recognizable Fortune 500 companies. If any of these companies were using simple SSO in Freshdesk, they were at risk.

Contact, Fix and Disclosure

We contacted Freshdesk via their security contact information with encrypted details of the vulnerability on April 20th and unfortunately did not receive a response. So I personally reached out to their CEO via LinkedIn’s InMail on Friday, April 22nd and received an immediate response.

He initially suspected I might be trying to sell him something, but once he understood the magnitude of the problem we had discovered, the team became responsive and we started moving towards getting a fix into production.

Freshdesk released a fix to production on April 26th. This fix required that their customers upgrade their software locally. We suspected that they might get push-back from their customers because of the very short upgrade window, so we held off on disclosing this vulnerability. As it turns out, that is what happened and Freshdesk wanted to extend support for the old SSO mechanism until May 3rd.

Someone on Freshdesk’s forums reverse engineered the fix that Freshdesk had released, figured out that a vulnerability had been fixed and decided to publicly disclose the existence of the vulnerability on the forums. This forced Freshdesk to terminate support for the old SSO mechanism early and they stopped supporting the old mechanism on May 1st, shortening the upgrade time for their customers by 2 days.

We have verified that, at least for our account, the old Freshdesk SSO mechanism is no longer supported. Freshdesk have posted a full incident report here.

Comments about Red Team Exercises

At Wordfence we are required to be PCI compliant and as part of that process we conduct regular PCI scans of our network to ensure it stays secure. We find that the scans provided are not enough to ensure that our network stays as secure as possible so we take the additional step of conducting our own external and internal security scans which go deeper than our regular PCI scan and we fix any vulnerabilities we find.

In addition to PCI compliance and our own manual scanning, it is Wordfence policy to regularly conduct red team exercises on our network. We do this to ensure that our customer data, source code, infrastructure and intellectual property is protected.

A red team exercise is a simulated attack that we conduct on our network. The attackers are a small group – one or two people. The team is not given any notification that the attack is going to occur and they are not told when it is in progress. The attackers take care to not impact production systems and their goal is to demonstrate as conclusively as possible vulnerabilities in our security posture. The Freshdesk vulnerability we disclosed today is an example of the product of this kind of exercise.

The benefit of a red team exercise is that it involves human intelligence and a real life attacker that is analyzing, probing and attacking a network in the same way that a real attack would occur.

If you are a larger company and have the resources to conduct a red team exercise, I would encourage you to do so on a regular basis and you may be surprised what turns up. Here are a few suggestions to help you conduct an effective red team exercise:

  • The only people who should know about the exercise should be a single top level exec (preferably the CEO) and the attackers.
  • Clearly define what the scope is of the exercise e.g. Define an IP block and the kinds of attacks and applications that may be targeted. Make it clear if external SaaS providers are targets and the kind of targeting that can be done on them.
  • Make it clear that production applications and services should not be put at risk. Customer data should also never be put at risk or removed from site (exfiltrated).
  • Avoid any mention of the exercise to other team members until it is complete.
  • Try to limit the time frame of the exercise as tightly as possible. The reason this is important is because if a vulnerability is found that is serious, it becomes very difficult to fix it while simultaneously keeping the red team exercise a secret.
  • Once the exercise is complete, a comprehensive report should be shared with the whole organization and should result in action items for the decision makers which are prioritized by level of urgency and level of effort.

Details of the Freshdesk Vulnerability

We are including the full details of the vulnerability we sent Freshdesk below. If you are a Freshdesk customer, you should have already been contacted by Freshdesk about this vulnerability and should have already upgraded.

Dear Freshdesk,

The Wordfence Research Team has discovered a serious vulnerability in Freshdesk. The vulnerability details are below. Please note that we use this product and the impact on the security of our customers and our business is severe.

As a cloud provider to Wordfence, we require that you respond to this immediately. We require notification that you have received this notice and a timeline of when a fix will be released. We expect this to be given the highest priority in your organization because it impacts your other customers too.

As per our standard disclosure process, we will notify our customers and the general public about this vulnerability within 30 days or on the day you release a fix, whichever is soonest. [Editor’s note: We decided to hold off on this aggressive schedule to allow the Freshdesk’s customers time to update]

The vulnerability details are as follows:

Vendor name: Freshdesk Inc
Product name: Freshdesk
Vulnerability type: Horizontal and Vertical Privilege Escalation in Single Sign On
Date discovered: April 14, 2016
Vulnerability technical details:

The Single Sign On/Remote Authentication process described in this article is insecure:

A user in a third-party system can choose a name and email that, when combined and hashed, matches the hash of another user.

For example, assume the following user is an administrator of
Name: John

An attacker could create a user account in the third-party system with these values:
Name: Johnj

When attempting to use SSO to access the attacker can authenticate with the third-party system and capture the SSO login URL:

The attacker can then edit the name and email parameters to match the admin user (the hash already matches):

Re-submitting the request will give the attacker access to the administrator’s account.

This vulnerability has been successfully exploited using and

We may confidentially notify interested parties both inside and outside our organization before the announcement date.

You should be aware that other researchers may discover this vulnerability and announce it prematurely. You should also note that this vulnerability may be exploited in the wild already. For these reasons we encourage you to release a fix as soon as possible to help protect your customers.

Please notify us as soon as this issue is resolved.

Kind regards,

Sean Murphy / Senior Developer / Wordfence
4948 DD81 CF99 3510 DFF0 44A6 A6D8 401E D683 98F5

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  • Nicely done! Kudos! Sounds like fun. :)

  • Great job guys and gals, I always find your blog informative and timely. Keep up the good work. Oh, and thank you for offering your Wordfence plug in for those of us who want to keep our blogs from becoming bots.

  • Ouch! What a straight-forward exploit. Good on your team for finding it and responsibly reporting it, but a sad commentary on the weak programming standards employed at Freshdesk.

  • You guys never stop to amaze me.

  • Fantastic Job!

    It feel so good to know that the best security plug-in on the net is doing its job in protecting its users and staying up-to-date with current ways of attacking sites.

    Keep up the good work. I love my WF and WF team. <3

  • Years ago I was asked to conduct such an exercise by the Chief of a major city's police department. But he wanted to see if I could physically penetrate their computer center.

    Disguised as an IBM employee (three piece suit and wingtips) I easily found the facility thanks to a sign with an arrow that said "Computer Center this way." When I reached the door it had a cypher lock, but was propped open with a trash can.

    Inside, no one asked my business, so I left a brief case next their big IBM 360 CPU (yes, that long ago) with a note in it with pasted on letters that said "Bang You're Dead", and left.

    I called the Chief and told him what had happened. He called out the SWAT team and bomb disposal group, and everyone from the IT head down to the computer operator learned a good lesson in physical security.

    But the point to the whole story is it's helpful, sometimes, to have trusted outsiders conduct the break-in whether physical or virtual.

    Insider or outsider, you can know too much or too little. What I didn't know was there eason for the exercise is that an informant's named had recently shown up on a payroll list. What they didn't know was the computer operator was a drug king-pin's girlfriend and an informer herself.

    • Amazing! Kudos to your talents.

  • I agree, red team exercises on a site can be extremely helpful in pinpointing security concerns. This is especially so when the timepoints for entry/attack mimic the standard time slots that hackers like to utilize. I would suggest that a company that has the capability to do so, consider doing a red team exercise every six months. I think that a year is too long.

    This red team exercise on yourself, working with the affected company to resolve the issue, and then informing the public is another example of showing the dedication of you guys to web security. Outstanding!!

  • I sleep better now that I have Wordfence on all of the sites I maintain. Any time I meet another wordpress designer I let them now about Wordfence. Thank you so very much for all the hard work you guys/gals put into helping make our web world that much more secure.

    To Tom: Your story about sneaking into the computer center for the Police Chief was great. Cue 007 theme music. :)

  • Wow, your team is amazing! Good info on a red team exercise.

  • Great post Sean. Thank you for sharing.

  • Professional & well handled - very happy to be supporting you guys! Keep up the good fight!.

  • Great job.. I was afraid... But now happy

  • I wondered why I had been seeing a recent influx of "" users registering lately. Glad I remove those immediately. Congrats on getting this fixed before it was a big problem!

  • Again!
    Great work by you and your team.
    Thanks again!

  • Great Job.

    Thank you.