Federal investigators find evidence of previously unknown tactics used to penetrate government networks

Federal investigators reported on evidence of previously unknown tactics for penetrating government computer networks, a development that underscores the disastrous reach of Russia’s recent intrusions and the logistical nightmare facing federal officials trying to purge intruders from key systems. While many details remained unclear, the revelation about new modes of attack raises fresh questions about the access that Russian hackers were able to gain in government and corporate systems worldwide.