WhatsApp doesn’t delete your ‘deleted’ messages

The iOS app’s vulnerability dents WhatsApp’s security credentials

WhatsApp still stores your conversations even if you delete them, a security researcher has discovered.

The latest version of the iOS app leaves a forensic trace of chats whether or not you delete, clear, or archive your messages, iOS security expert Jonathan Zdziarski said in a blog post yesterday.

The problem, Zdziarski explained, is that once WhatsApp messages are deleted, they enter a "free list" stored locally on your application's SQLite database, and are not deleted from the device until the database needs to free up storage space.

Advertisement - Article continues below

As the researcher said: "The core issue here is that ephemeral communication is not ephemeral on disk."

But he added: "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."

This might not be a problem if it were not for the fact that this database of stored messages is sent into your iCloud in routine backups, if you have those enabled.

While WhatsApp recently boosted its security credentials by making end-to-end encryption over the air standard for all types of communication on the platform, iCloud does not allow you to encrypt any backups.

Advertisement - Article continues below

Zdziarski said: "Law enforcement can potentially issue a warrant with Apple to obtain your deleted WhatsApp chat logs, which may include deleted messages. None of your iCloud backup content will be encrypted with your backup password (that's on Apple, not WhatsApp)."

Advertisement - Article continues below

Those relying on using iTunes's Encrypt Backups' option on desktop backups, rather than backing up to iCloud, could fall foul of forensics tools designed to hack passwords, he added.

To mitigate the security risk, the researcher recommended setting up a complex backup password for your iOS device that is not stored in the keychain.

He also urged people to disable iCloud backups, due to iCloud not supporting encryption, and to periodically delete the WhatsApp app in order to flush out the database of deleted records. 

On WhatsApp, Zdziarski said: "A poor design choice could quite realistically result in innocent people sometimes people crucial to liberty being imprisoned.

"The SQLite database does not need to come off in a backup at all. The file itself can be marked in such a way that it will not be backed up. The manufacturer may have set this behavior so that restoring to a new device will not cause you to lose your message history. Unfortunately, the tradeoff for this feature is that it becomes much easier to obtain a copy of this database."

Featured Resources

Navigating the new normal: A fast guide to remote working

A smooth transition will support operations for years to come

Download now

Putting a spotlight on cyber security

An examination of the current cyber security landscape

Download now

The economics of infrastructure scalability

Find the most cost-effective and least risky way to scale

Download now

IT operations overload hinders digital transformation

Clearing the path towards a modernised system of agreement

Download now


ethical hacking

Mobile banking apps are exposing user data to attackers

26 Jun 2020

Most malware came through HTTPS connections in Q1 2020

25 Jun 2020

Phishing attacks target unsuspecting Wells Fargo customers

24 Jun 2020

Trump administration wants to enhance the security of .gov sites

24 Jun 2020

Most Popular


How to find RAM speed, size and type

24 Jun 2020

Microsoft releases urgent patch for high-risk Windows 10 flaws

1 Jul 2020
Policy & legislation

UK gov buys "wrong" satellites in £500m blunder

29 Jun 2020