Twitter Turns Off Tweeting via SMS After CEO Hack

Twitter on Wednesday halted users' ability to fire off tweets via text messages as it seeks to fix a vulnerability that led to CEO Jack Dorsey's account being hijacked.

Dorsey last week was the target of so-called "SIM swap" fraud, which enables a hacker to trick a mobile carrier into transferring a number - potentially causing people to lose control not only of social media, but bank accounts and other sensitive information.

This type of attack targets a weakness in the use of "two-factor authentication" via text message to validate access to an account, a break-in method that has grown popular in recent years.

"We're temporarily turning off the ability to Tweet via SMS, or text message, to protect people's accounts," the Twitter support team wrote on the platform.

"We're taking this step because of vulnerabilities that need to be addressed by mobile carriers and our reliance on having a linked phone number for two-factor authentication."

The San Francisco-based service added that as it works on a long-term solution to the problem, tweeting via text message eventually will be turned back on in markets where users rely on that technique.

Even with considerable security precautions in place, Dorsey became the victim of the embarrassing compromise when attackers hijacked his phone number and took control of his Twitter account.

Dorsey's account was restored after a brief period during which the attackers posted a series of offensive tweets.

Some analysts say hackers have found ways to easily get enough information to convince a telecom carrier to transfer a number to a fraudster's account, especially after hacks of large databases that result in personal data sold on the so-called "dark web."

"Mobile accounts' text messages can be hijacked by sophisticated hardware techniques, but also by so-called 'social engineering' -- convincing a mobile provider to migrate your account to another, unauthorized phone," said R. David Edelman, a former White House adviser who heads a cybersecurity research center at the Massachusetts Institute of Technology.

"It only takes a few minutes of confusion to make mischief like Dorsey experienced."