Thinking that deleting your WhatsApp chat is good enough to erase it from existence? Maybe if you’re trying to hide a conversation from someone not so tech savvy, we guess maybe it could work, but for those who are more skilled, like law enforcement agencies or security researchers, it seems that your deleted chats aren’t 100% deleted.
According to a post by security researcher Jonathan Zdziarski, he has examined disk images from the latest build of WhatsApp and discovered that your deleted chats aren’t actually fully gone from your phone. Instead it seems that there is a forensic trace of the chat logs left behind, meaning that for the person with the right skills, it’s almost as good as if the chats weren’t deleted in the first place.
Zdziarski notes that this problem is solely a WhatsApp problem, but rather with apps on iOS that rely on SQLite, and that deleting a record basically adds it to something called a “free list”. “If you delete large chunks of messages at once, this causes large chunks of records to end up on this ‘free list’, and ultimately takes even longer for data to be overwritten by new data. There is no guarantee the data will be overwritten by the next set of messages. In other apps, I’ve often seen artifacts remain in the database for months.”
So like we said, anyone with the tools could potentially gain access to your messages. Zdziarski also provided some tips and how end-users could potentially protect themselves, and also how developers such as WhatsApp could mitigate this problem in future builds, something that we hope the company will pick up on.