June 11, 2015
Cleaning up after the attack could cost millions of euros and involve replacing or wiping computers, said Sueddeutsche Zeitung.
Federal investigators are looking into the scope of the attack to see how much data has been taken.
It is still not clear who carried out the cyber-attack.
The attack on the lower house of the German parliament came to light in May.
It involved attackers using malicious programs to infect many of the 20,000 machines used by politicians, support staff and civil servants that sit on the Parlakom network.
German newspaper Der Spiegel quoted a parliamentary source who said the malware was still “active” and stealing data from infected machines.