By Max Hunder and Yuliia Dysa KYIV (Reuters) -Ukraine’s biggest mobile network operator, Kyivstar, was hit on Tuesday by what appeared to be the biggest cyber attack of the war with Russia so far, knocking out mobile and internet services for millions. Kyivstar has 24.3 million mobile subscribers – more than half of Ukraine’s population – as well as over 1.1 million home internet subscribers. Its CEO Oleksandr Komarov said the attack was “a result of” the war with Russia, although he did not say which Russian body he believed to be responsible, and that the company’s IT infrastructure had been…