Monthly Archives: January 2018

Tinder Mobile Take-Aways

While browsing through the news I noticed an article talking about the Tinder mobile app and a privacy concern. You can read the article at https://www.consumerreports.org/privacy/tinder-app-security-flaws-put-users-privacy-at-risk/. To summarize what is considered the issue is that the mobile application does not transmit the photos that you see using HTTPS. This means that anyone on the same connection can see the traffic and, ultimately, see the photos you are presented. From my understanding, it doesn’t appear the potential attacker can tell who the user is that is viewing these photos as the rest of the traffic is properly using HTTPS.

We have discussed the move to all HTTPS multiple times on this blog and we are seeing a lot of sites making the switch. With web applications it is easy to see if the site is using HTTPS or not with the indicators near the address bar. Of course, these indicators are often confusing to most, but at least we have the ability to see the status. With a mobile application it is much more difficult to tell if data is transmitted using HTTPS or not because there is no visible indicator. Instead, one needs to view the raw traffic or use a web proxy to see how the data is transmitted. This can be misleading to many people because the assumption is that the data is protected because it is hidden under more layers.

In this instance, the ability to see these photos may not be considered that sensitive by many. Assuming that anyone can create an account and see the photos doesn’t make them a secret. People have opted to post their images for others to find them on the network. Of course, level of sensitivity is in the eye of the beholder these days. Another issue that is potentially possible in this situation is that the attacker could manipulate that image traffic to show a different image. This could lead to the end user seeing a different image than the one expected. The usefulness of this could be called into question at any type of large scale.

The take-away here is that when we are building applications we must take care in understanding how we are transmitting all of our data to determine what needs to be protected. As I mentioned, there is already a push to make everything HTTPS all the time. If you have decided not to use HTTPS for your connections, have you documented the reasons? What does your threat model tell you about the risks with that data and its communication. How does that risk line up with your acceptance procedures.

Another interesting tidbit came out of the article mentioned above. In addition to seeing the actual photos, they found it was possible to identify whether or not the end user liked or disliked the photo by comparing the network traffic. The interesting part about this part is that those decisions were encrypted when transmitted. The key point here is that the traffic for each decision was a set size and the sizes were different for like and dislike. By viewing the traffic after seeing a photo, it is possible to determine which ones were liked based on the size of the requests. In this case, it still doesn’t identify the end user that is using the application.

We don’t typically spend a lot of time analyzing the size of the requests we send in the event someone may try to determine what actions we are taking over an encrypted channel. Most of the time these actions are not possible to determine, or the level of effort is way above what is realistic. The easy solution would be to make sure all traffic was encrypted and we wouldn’t be able to know what images were liked or disliked. Maybe it would be possible to still see the difference, but with no way to tie it to specific images. The other option is to attempt to pad the requests so that they are all the same size. This would be for highly sensitive systems as the complexity may not be worth the benefit.

Of course, all of this is based on the attacker being on the same network as the end user so they can intercept or view the traffic in the first place. In the case of a public place, it might just be easier to hover over your shoulder and watch you use the app then intercept the traffic and guess at who is using it.

Both of these topics are good conversation starters within your organization. They help us realize that even just one request that doesn’t use HTTPS may be seen and could raise an issue. It also helps us to see that sometimes even encrypted data can be determined, but that doesn’t mean it is a high risk. Each situation is different and should be properly analyzed to determine the risk it creates for the company and the organization.

New Year’s Resolutions

Here we are, the start of another year. As we reflect on 2017, this is where we really start to focus on what lies ahead in 2018. The new year is always interesting because it usually doesn’t affect our build cycles or releases. With the exception of accounting for vacations. Yet, this is the time of year where many people get re-focused and motivated to change old habits or try something new.

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As I look back on 2017, there were a lot of news headlines that focused around security. So many of them highlighting breaches, many termed “mega” breaches. The trend of hyped up headlines glorifying monster breaches will likely continue through 2018 and beyond. We know that breaches can, or will, happen. We have seen examples of different techniques used to gain unauthorized access to data. This won’t change, and will most likely become more prevalent going forward. The amount of information available to potential attackers is enormous, making our job of application security that much more important.

One of the biggest lessons to take away from 2017 is that privacy is important. In addition, private data is not limited to PCI or HIPAA. All sorts of data can be considered private and require the custodian to take proper steps to protect it. It doesn’t matter if the data is held by a Fortune 500 company or a one-person shop. To someone, that data is worth something. As we look into 2018, this reminds us that we must understand what data we have. We must know what type of regulations it may fall under, what applications contain it, and how we are protecting it. Just because data may not fall under a regulation doesn’t mean it should be overlooked. In the end, it is the expectation of our customers and clients that we will handle their data responsibly.

Protecting this data is not about how much money you spend or what tools you buy. Every organization is different. Every application development team is different. I encourage everyone to take the time to research and understand what your team needs to be successful. As in the past, throughout the year I will be posting thoughts on different application security topics. If you have any questions or topics, feel free to share them with me. Looking for someone to talk to about application security? Reach out. I have services available to help organizations and individuals reach new heights and solve problems.

What are your New Year’s Resolutions when it comes to application security?