Time Warner Cable has revealed that data up to 320,000 of its customers may have had their data compromised.

The cable telecommunications company, which is one of the biggest in the US, said that it has yet to identify how the information – emails and passwords – was accessed.

It has notified the FBI of the incident and is currently in the process of informing those it believes may have been affected.

"Approximately 320,000 customers across our markets could be impacted by this situation."

“Approximately 320,000 customers across our markets could be impacted by this situation,” Eric Mangan, director of public relations, was quoted by VentureBeat as saying.

“To protect the security of these customers, we are sending emails and direct mail correspondence to encourage them to update their email password as a precaution.”

Time Warner Cable is confident that this incident is not the result of a direct data breach, with Reuters reporting that the information may have been accessed through phishing or indirectly through data breaches at other companies.

This isn’t the first time that the company has hit the headlines over security-related issues. In 2009, a blogger by the name of David Chen discovered a vulnerability in a Time Warner/Road Runner modem and Wi-Fi router.

“After poking around using the customer account, I found that access to the admin features of the router has been disabled via Javascript,” ZDNet quoted him saying at the time.

“You heard me correct, the web admin for the router simply uses a script to hide certain menu options when the user does not have admin privileges.

“By simply disabling Javascript in the browser, I was able to access all the features of the router. With that access, I am now able to change the wifi settings, port-forwarding, etc.”