text: A recent cyber-attack on the State Department was reportedly carried out by high-level Russia hackers who also penetrated restricted parts of the White House computer system, such as the president's private schedule. CNN reported Tuesday, citing US officials briefed on the months-long investigation conducted by the FBI and Secret Service, that the hackers were able to access real-time, non-public schedule of President Obama, which is regarded as highly sensitive information that is sought after by foreign intelligence agencies. In October 2014, the White House acknowledged that there had been suspicious activity on its unclassified network serving the executive office, prompting system shutdowns and security upgrades. Vulnerable: A new report has revealed that Russian hackers launched a cyber-attack against White House's unclassified computer network last year . Privacy concerns: The hackers reportedly accessed President Obama's non-public schedule, which is considered highly sensitive information . Sneak attack: According to federal officials involved in the probe, the hackers wormed their way into the White House system by breaching first the State Department's network . A six-month investigation into the breach, described as one of the most sophisticated attacks against the US, reportedly uncovered evidence pointing to hackers working on behalf of Russian President Vladimir Putin's government. According to federal officials involved in the probe, the hackers wormed their way into the White House system by breaching first the State Department's network. To accomplish this task, the cyber-bandits allegedly working for the Kremlin commandeered a State Department email account and sent a phishing email to someone at the White House designed to trick the recipient into downloading malicious software. Silver lining: White House deputy national security adviser Ben Rhodes said last year's cyber intrusions that did not affect classified information . Once downloaded onto a White House computer, the malware presumably allowed the hackers to penetrate the unclassified network containing Obama's schedule that is not accessible to the general public. According to an anonymous government official, the hackers have been able to re-enter the State Department computer system, despite efforts to keep them out. The Russian Embassy did not publicly comment on the hacking allegations . The White House responded to CNN’s revelations by saying the report did not refer to a new incident but was ‘speculating’ about the source of cyber activities that were disclosed last year. Spokesman Mark Stroh said in a statement that the White House would not comment on CNN's attribution of the cyber-attack to Russian hackers. ‘Any such activity is something we take very seriously. In this case, as we made clear at the time, we took immediate measures to evaluate and mitigate the activity,’ Stroh stated. ‘As has been our position, we are not going to comment on the referenced article's attribution to specific actors.’ White House deputy national security adviser Ben Rhodes said in an appearance on CNN Tuesday that the White House in 2014 disclosed cyber intrusions that did not affect classified information. ‘We have an unclassified system and then we have a classified system, a top secret system,’ Rhodes said. ‘We do not believe that our classified systems were compromised.’ But he said, ‘There's always vulnerability.’ For that reason, Rhodes said the White House operates a separate, secure system for classified data. He assured the public that the White House takes regular actions to prevent intrusions on its unclassified network.
target: Hackers reportedly wormed their way into the White House system by breaching the State Department's network first .
  Cyber-bandits took over a State Department email account and sent phishing email containing malware to White House .
  Obama aide said White House in 2014 disclosed cyber intrusions that did not affect classified information .
  Six-month probe reportedly uncovered evidence pointing to hackers working on behalf of Kremlin .