Russian Espionage Group Tapped Microsoft Corporate E-Mails

Microsoft on Friday announced that it was the victim of password spray attacks by "Midnight Blizzard," a Russian state-sponsored actor, formerly called "Nobelium."

The attacks, which breached some of Microsoft's corporate e-mail accounts, possibly over a month's period of time, were found to have started in "late November 2023." Microsoft only detected the issue "on January 12, 2024." The attackers were looking for Microsoft's knowledge about themselves, apparently, per Microsoft's investigation.

The investigation indicates they [the attackers] were initially targeting email accounts for information related to Midnight Blizzard itself. We are in the process of notifying employees whose email was accessed.

The attackers accessed some senior leadership Microsoft corporate e-mails, as well as any attachments. Microsoft doesn't think that its customer accounts were affected by the attack. It is disclosing information about it as part of its Secure Future Initiative pledge of transparency.

In password spray attacks, commonly used passwords are tried across a network to gain access. In this case, the threat actors managed to gain password access on old nonproduction Microsoft test accounts. From that foothold, the attackers were able to gain permissions and "access a very small percentage of Microsoft corporate email accounts, including members of our senior leadership team and employees in our cybersecurity, legal, and other functions," the announcement indicated.

In reaction to the breach, Microsoft pledged to "act immediately to apply our current security standards to Microsoft-owned legacy systems and internal business processes, even when these changes might cause disruption to existing business processes."

Microsoft is continuing its investigation and declared that it plans to "take additional actions based on the outcomes of this investigation and will continue working with law enforcement and appropriate regulators."

The Midnight Blizzard attack group used to be called "Nobelium" by Microsoft back in 2021 when they had conducted widespread espionage on U.S. government agencies, compromising Exchange Online e-mails through various methods. Microsoft switched to a bad weather naming convention for attack groups last year.

Microsoft initially had dubbed the 2021 attacks on U.S. government agencies "Solorigate."  SolarWinds' Orion software had been one attack venues used back then via a supply-chain compromise, but the attackers also leveraged misconfigurations in Microsoft's Active Directory Federation Services, among other methods, to carry out espionage.

In a Jan. 19 exTwitter post, John Hultquist, chief analyst at Mandiant Intelligence, noted that "APT29/Cozy Bear/Midnight Blizzard is the Russian SVR crew that pulled off SolarWinds."

SVR is Russia's foreign intelligence service. Password spray attacks have long been a favored attack method of this group, per this summary by the U.S. Cybersecurity and Infrastructure Security Agency.

About the Author

Kurt Mackie is senior news producer for 1105 Media's Converge360 group.


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