Twitter has disclosed a data leak related to a bug in one of its support forms and now suspects the activity could be the work of nation-state actors.

On Nov. 15, 2018, the social platform learned of a problem in a support form used by account holders to report issues to Twitter. The bug could be used to learn the country code of phone numbers associated with different accounts, as well as whether the account had been locked. Twitter locks accounts if they appear to be compromised or violate its rules or terms of service.

The issue was resolved by Nov. 16. Since then, Twitter has been investigating its origin and background. In a support page published on Dec. 17, it reports "unusual activity" involving the affected support forum's API, particularly 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," the support page explains.

Compared with breaches stemming from other social platforms – the September Facebook breach, for example, or the recent  Google+ vulnerability – this incident puts less personal data at risk. However, the nature of activity surrounding this issue is concerning. Country codes can be used by nation-states to map the general location of people they might want to pursue.

Twitter reports no action is required by account holders and the problem has been resolved.

"We are providing this broader notice as it is possible that other account holders we cannot identify were potentially impacted," officials write. Affected users have been informed.

Related Content: