This content was produced in Russia where the law restricts coverage of Russian military operations in Ukraine
MOSCOW, Dec 6 (Reuters) - Russia's No. 2 bank VTB was hit by the largest cyber attack in its history, it said on Tuesday, warning of temporary difficulties in accessing its mobile app and website, but assuring customers that their data remained safe.
State-owned VTB said it was repelling the distributed denial of service (DDoS) attack, in which hackers attempt to flood a network with unusually high volumes of data traffic in order to paralyse it.
"The bank's technological infrastructure is under an unprecedented cyber attack from abroad," VTB said in a statement. "The largest not only this year, but in the whole time the bank has operated."
Russian government entities and state-owned companies have been targeted over events in Ukraine, with the websites of the Kremlin, flagship carrier Aeroflot and major lender Sberbank among those to have seen outages or temporary access issues.
Hackers also delayed the start of President Vladimir Putin's speech at Russia's flagship economic forum earlier this year.
Pro-Russian hackers, meanwhile, have claimed responsibility or been blamed for attacks on websites and infrastructure in the likes of Lithuania, Norway and the United States this year.
VTB said the majority of attacks had come from abroad, but that it was particularly concerned by traffic from Russian IP addresses. It said it would hand over all identified Russian IP addresses to law enforcement. (Reporting by Alexander Marrow, Editing by Louise Heavens)