The move comes after hackers infiltrated Twitter CEO Jack Dorey's account.

The timing of the attack coincides roughly with the pro-democracy demonstrations in Hong Kong.

Twitter does not know how many people were impacted by the error.

Here's a reminder of the ease with which crooks can hide their malware in popular app hubs.

A piece of malware pretending to be an Android system update was downloaded over 1 million times since launch 2014. The malware, dubbed SMSVova, spied on a victim's location and relayed it to the attacker in real time.

Facebook's instant verification is potentially a significant user experience step forward. But it still falls back on SMS verification, which is widely seen as insecure and worth leaving behind.