A1 Telekom Austria is the leading fixed and mobile network operator in Austria, with 5.4 million mobile and 2.3 million fixed-line customers. The incident took place in November 2019, when the systems at the company have been infected with malware. Attackers have disseminated hidden backdoors in the company network. The company has reset passwords for all its 8,000+ employees and has changed passwords and access keys for all servers. It is not clear if the attackers were nation-state attackers of financially-motivated hackers.”]
Source: https://securityaffairs.co/wordpress/104631/hacking/a1-hacked.html