Privacy Risk Assessment on Online Photos

With the rising popularity of cameras and people’s increasing desire to share photos, an overwhelming number of photos have been posted all over the Web. A digital photo usually contains much information in its metadata. Once published online, a photo could disclose much more information beyond what is visually depicted in the photo and what the owner expects to share. The metadata contained in digital photos could pose significant privacy threats to their owners. Our work aims to raise public awareness of privacy risks resulting from sharing photos online and subsequent photo handling conducted by contemporary media sites. To this end, we investigated the prevalence of metadata information among digital photos and assessed the potential privacy risks arising from the metadata information. We also studied the policies adopted by online media sites on handling the metadata information embedded in the photos they host. We examined nearly 100,000 photos collected from over 600 top-ranked websites in seven categories and found that the photo handling policy adopted by a site largely varies depending on the category of the site. We demonstrated that some trivial looking metadata information suffices to mount real-world attacks against photo owners.