Twitter today published a new update on its recent security incident, confirming a small number of employees were targeted in a phone spear-phishing attack. The intruders were able to use their credentials to tweet from celebrity accounts, access direct messages, and download data.
The attack, which took place earlier this month and involved the takeover of several high-profile Twitter accounts, raised concerns over Twitter's internal controls and the level of access its employees have to high-profile accounts. The company has since published multiple updates on its ongoing investigation and the steps it's taking to improve account and employee security.
"This attack relied on a significant and concerted attempt to mislead certain employees and exploit human vulnerabilities to gain access to our internal systems," Twitter said in an update published yesterday.
A successful attack required access to both Twitter's internal network and employee credentials to specific support tools. Not all employees initially targeted had permissions to use account management tools, but the attackers used their credentials to access internal systems and gain information about its processes. This enabled the attackers to target 130 Twitter accounts and tweet from 45, access the DM inboxes of 36, and download the Twitter data of seven.
In addition to confirming the mobile spear-phishing attack vector, Twitter claims it has "significantly limited" access to its internal tools and systems while its investigation continues. Some processes and features -- in particular, access to the "Your Twitter Data" download feature -- have been affected. The company says it may be slower in response to account support needs, reported tweets, and applications to its developer platform.
Read more details in Twitter's full update.