A Chinese tech blogger dropped a bombshell last Friday, claiming on Chinese media that he found that several popular Chinese apps, including the Tencent-owned chat apps WeChat and QQ, as well as the Alibaba-owned ecommerce app Taobao, frequently access iPhone users' photo albums in the background even when those apps are not in use.
The original Weibo post from the tech blogger, using the handle of @Hackl0us, provoked intense debates about user privacy on the Chinese internet and consequently prompted WeChat to announce that it would stop fetching users' photo album data in the background.
@Hackl0us said he tracked the apps' activities for seven days using a new iOS 15 feature called Record App Activity, along with a third-party app called App Privacy Insights. Screenshots of activity logs provided by @Hackl0us show that the three Chinese apps read his photos multiple times throughout the day with each read lasting up to 60 seconds.
"This is disgusting," @Hackl0us wrote. "Photos are a user's private [possession]. They have no idea when the apps fetch their private data. Judging from the log, the apps read the photo library even while the user is asleep."
Chinese web users reacted strongly to @Hackl0us' findings. His original Weibo post trended on the platform's hot search chart last Friday. By the time of this writing, his post has been shared over 50,000 times, and nearly 220,000 people have liked it. A related hashtag has received 200 million reads. In a survey launched by Sina Tech on Weibo, 94% of some 30,000 respondents said they are not comfortable with apps reading their photo libraries.
WeChat, one of the most frequently used apps in China with over 1.2 billion users, immediately responded through Chinese media. The company explained that an Apple protocol, which web users identified as the PHPhotoLibraryChangeObserver, notifies app developers of changes that occur in their user' photos libraries. The protocol allows an app to track changes within and outside the app. When an app receives those change messages, the iOS 15 system records the activity as if it were photos being read on a user's phone.
WeChat explained this protocol allows users to share photos faster in chats, causing a preview of the last photo in a user's album to pop up. WeChat stressed in its statement that the processing is on-device, and that app was able to do this because users gave their consent by authorizing WeChat to access their albums.
"We do not collect, save, or upload any images from a user's album without the user's authorization," a Tencent spokesperson wrote in a statement shared with Protocol.
WeChat promised that it would withdraw the background fetching protocol in its next update, and it is finding an alternative to "optimize the quick picture sending function.
But WeChat's statement didn't fully address privacy concerns. In a Zhihu article where @Hackl0us documented his complaint, he wrote that WeChat's technical teams had reached out to him and explained why WeChat decided to enable the image posting feature through background data fetching. But @Hackl0us believes WeChat is breaking a butterfly on a wheel. He argued that WeChat could achieve the same feature in alternative ways without systematically reading photo libraries in the background. Not only does invoking this protocol intrude on user privacy, @Hackl0us said, it consumes unnecessary memory and battery at the expense of user experience.
"I really don't understand why WeChat needs to use Apple's PHPhotoLibraryChangeObserver protocol to implement such a simple feature," he wrote. "It's probably fine for one app to do this, but if many Chinese apps act like this, and they do, it will have a big impact on our phone's battery life."
Legitimate privacy concerns
Digital privacy experts told Protocol that app developers seeing a list of photo changes by itself offers very limited utility, but if the apps can access the photos themselves, they could exploit Apple's PHPhotoLibraryChangeObserver protocol to analyze user behavior or sentiment, which is of great commercial value. Apps could also run facial recognition algorithms to facilitate social mapping.
"WeChat is closed-source software, so it is impossible to know how the protocol is implemented, what it does, and whether it is commercialized by generating a library of fingerprints from user albums until we see the source code," @Hackl0us wrote in his Zhihu article.
The controversy over privacy occurred less than one month before China's privacy law, the Personal Information Protection Law (PIPL), becomes effective. This law will shield Chinese internet users from excessive data collection and misuse of personal data by tech companies. One big theme running throughout the law is ensuring the consumer's right to consent and the right to know how their information is being used. Data handlers are required to collect data only when necessary to provide certain services, and must secure user consent for the collection.
Without knowing more details of app developers' processes on the device and regulations, it's hard to know whether the action of frequently reading photo albums would violate the forthcoming Personal Information Protection Law, according to Graham Webster, a research scholar at the Stanford University Cyber Policy Center and the editor in chief of the center's DigiChina Project.
"One real question is whether on-device processes limited to functional needs for the app even constitute 'personal information handling' under the law," Webster told Protocol. "Meanwhile, it seems it would be impossible to know ahead of time whether a given photo qualifies as 'sensitive personal information.'"
Under PIPL, data handlers are required to obtain "separate consent" from users while dealing with "sensitive personal information" and inform them of the necessity of collecting such data as well as the impact on their rights.
The law is new. Companies and consumers should expect more detailed regulations to clarify questions like this. "Depending on the details, [the background fetching of albums data] could well be a legitimate privacy concern, even if it isn't one that's covered in the new law," Webster said.
