July 4, 2020

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Twitter API abused to match of usernames to phone numbers – Security

State-sponsored risk actors are thought to have exploited social community Twitter’s application programming interface (API)...

State-sponsored risk actors are thought to have exploited social community Twitter’s application programming interface (API) to match usernames to cell phone numbers.

Twitter identified an unnamed actor working with a substantial community of faux accounts for the assault on Xmas Eve last yr.

The faux accounts have been suspended, and Twitter said they ended up found in a wide variety of nations.

Nonetheless, Twitter’s stability staffers found that a notably substantial volume of API requests arrived from net protocol addresses found in just Israel, Iran and Malaysia.

These IP addresses could have ties to point out sponsored actors, Twitter said.

The social community did not say how quite a few faux accounts ended up made use of for the assault, or how quite a few customers ended up targetted.

TechCrunch reported that a researcher, Ibrahim Balic, was capable to upload lists with around two billion cell phone numbers he experienced produced, and ordered randomly, to Twitter thanks to a flaw in the social network’s Android application.

Balic was capable to match 17 million cell phone numbers to user accounts around a interval of two months till Twitter blocked the API queries on December 20.

The researcher did not alert Twitter to the vulnerability, but made use of the cell phone numbers of substantial-profile customers these kinds of as politicians and govt officials and established up a WhatsApp team to warn them instantly.

Twitter said the API endpoint helps make it less complicated for new account holders to locate people today they may well currently know who are on the social community.

The API queries only labored versus accounts that experienced the “Enable people today who have your cell phone selection locate you on Twitter” enabled. Also, the accounts wanted to have a cell phone selection associated with them, which Twitter made use of to need of customers when it commenced off as an SMS-based service.

That’s when it really is made use of as intended exploiting the API to match usernames to cell phone numbers was “further than its intended use case” Twitter said.

It is no for a longer period probable to question the API and have it return the username associated with a cell phone selection.

Twitter apologised for the details leak but has not said it will contact these influenced by it.