EXIF data: a picture really is worth a thousand words

As technology continues to make the world more connected, privacy on the web is a growing concern. New innovations and social media tools have made information sharing easier than ever before, but what happens when we share without a full understanding of the data that tags along? This has become a serious issue with image sharing and the EXIF data contained in pictures.

What is EXIF data?

Exchangeable Image File Format data, or EXIF data, is the information about an image that is stored inside the image itself. This data includes the model of the camera or camera phone, the time the photo was taken, various camera settings, and in some cases, the location that the picture was taken.

Inspecting EXIF data is as simple as right clicking on the image and selecting ‘Properties,’ then going to the ‘Details’ tab, or opening the image and selecting ‘File Info’ (Figure 1).

What can this data be used for?

There are plenty of legitimate reasons to have EXIF data stored in pictures. The information can be used to prove the author of a photograph. EXIF data also contains useful information for anyone interested in seeing the settings used to capture a specific image. Having the geo-location enabled allows viewers to see exactly where an image was taken, which can be useful to anyone interested in exploring the picturesque area captured by a photographer.

Unfortunately, there are also more sinister uses for EXIF data. Doxxing is the practice of collecting personal data on one individual from multiple sources, packaging it together, and publishing it online. Historically, this has been done by hackers and hacktivists to embarrass and even expose their target to potential harm. EXIF data contains potentially damaging information that can be used by threat actors for doxxing, especially if the geo-location is turned on.

In targeted campaigns, threat actors can use EXIF data to learn more about their target and better tailor their attacks. The mobile device version has the potential to aid a persistent threat actor in their campaign.

The geo-location of an image may also be exploited by less technical criminals. This can range from thieves targeting an online add where the sale image still contains EXIF data, to giving up your location to unsavory characters.

A real world example of EXIF data being used in unintended ways occurred in 2014 when a Russian soldier posted pictures online.[1] The Russian government had actively denied having troops in Ukraine but when the soldier carelessly posted pictures to a social media app with the geotagging feature activated he gave up his operational security and let the whole world know he was stationed in the Ukraine.

What can you do to maintain your privacy?

Whether you are worried about security issues or just want to remain a bit more anonymous on the web, there are multiple ways to remove EXIF data from an image. Some social media sites, such as Facebook and Instagram, remove this data for all images uploaded. In these cases, it should be noted the company may retain the EXIF data themselves despite having made it impossible for others to access.

Window’s offers a mechanism to remove personal data from images called “Remove Properties and Personal Information” that can be found in the details section of an image. Although this removes some information it does not fully strip EXIF data. There are various apps that can be downloaded to automatically strip the EXIF data from photos; just be sure that the app you chose is trustworthy and does not retain any of the information it removes.

If you aren’t comfortable with these options, a more secure route is to take a screenshot of the photo you want to share. Rather than sharing the original photo, you can share the screenshot that does not contain any of the original EXIF data.

Remember that no matter what device you are using, geotagging can be disabled to ensure the EXIF data does not contain location. Most importantly, if you a worried that a picture may be misused if it is attributed to you, consider if it is worth posting in the first place.

ABOUT THE AUTHOR

eSentire Threat Intel Threat Intelligence Research Group