An army of volunteer hackers is rising up to defend Ukraine, although Internet specialists are calling on geeks and other “hacktivists” to stay out of a potentially dangerous computer war. Livia Tibirna, an analyst at cybersecurity firm Sekoia, said that nearly 260,000 people have joined the “IT Army” of volunteer hackers, which was set up at the initiative of Ukrainian First Vice Prime Minister and Minister of Digital Transformation Mykhailo Fedorov. The group, which can be accessed through the encrypted messaging service Telegram, has a list of potential targets in Russia, companies and institutions, for the hackers to target. It is difficult to