Twitter flags suspected state-sponsored attack after unusual activity from China and Saudi Arabia

Twitter has confirmed its platform was hit by a suspected state-sponsored attack last month, with a host of malicious actors taking advantage of a bug to harvest users' phone numbers.

In a statement released yesterday, the social networking platform said it became aware of a host of bugs being exploited by IP addresses based in China and Saudi Arabia and noticed unusual activity involving an affected customer support form API.

Requests made from these IP addresses, which Twitter has highlighted as being associated with state-sponsored actors, targeted the support form which reports issues to Twitter staff.

Two bugs, flagged on November 15 and fixed the following day, allowed an attacker to access a user's phone number and country code, as well as establish whether or not their account had been locked by Twitter.

"Since we became aware of the issue, we have been investigating the origins and background in order to provide you with as much information as possible," the company said in a statement.

"Specifically, we observed a large number of inquiries coming from individual IP addresses located in China and Saudi Arabia.

"While we cannot confirm intent or attribution for certain, it is possible that some of these IP addresses may have ties to state-sponsored actors."

Twitter said that no action was required by account holders and that the firm has informed law enforcement of the findings of its investigation.

The second bug, which allowed malicious actors to view whether a user's account had been locked, may seem relatively inane, but accessing a user's registered phone number constitutes a far more serious breach of privacy.

Throughout its history, the social networking platform has been ripe for exploitation by state-sponsored actors, as well as cyber criminals.

Researchers, for instance, outlined earlier this year how threat actors established a three-tier 'crypto-giveaway' botnet on the platform comprising millions of fake accounts.

The platform is also facing a General Data Protection Regulation (GDPR) probe over the handling of a user's subject access request (SAR), which Twitter had refused to comply with on the grounds it would take 'disproportionate effort'.