Recent 'MFA Bombing' Attacks Targeting Apple Users

An anonymous reader quotes a report from KrebsOnSecurity: Several Apple customers recently reported being targeted in elaborate phishing attacks that involve what appears to be a bug in Apple's password reset feature. In this scenario, a target's Apple devices are forced to display dozens of system-level prompts that prevent the devices from being used until the recipient responds 'Allow' or 'Don't Allow' to each prompt. Assuming the user manages not to fat-finger the wrong button on the umpteenth password reset request, the scammers will then call the victim while spoofing Apple support in the caller ID, saying the user's account is under attack and that Apple support needs to 'verify' a one-time code.

What sanely designed authentication system would send dozens of requests for a password change in the span of a few moments, when the first requests haven't even been acted on by the user? Could this be the result of a bug in Apple's systems? Kishan Bagaria is a hobbyist security researcher and engineer who founded the website texts.com (now owned by Automattic), and he's convinced Apple has a problem on its end. In August 2019, Bagaria reported to Apple a bug that allowed an exploit he dubbed 'AirDoS' because it could be used to let an attacker infinitely spam all nearby iOS devices with a system-level prompt to share a file via AirDrop -- a file-sharing capability built into Apple products.

Apple fixed that bug nearly four months later in December 2019, thanking Bagaria in the associated security bulletin. Bagaria said Apple's fix was to add stricter rate limiting on AirDrop requests, and he suspects that someone has figured out a way to bypass Apple's rate limit on how many of these password reset requests can be sent in a given timeframe. 'I think this could be a legit Apple rate limit bug that should be reported,' Bagaria said.

Read more of this story at Slashdot.