Government officials disclosed the hacks in a joint security advisory published by the Cybersecurity and Infrastructure Security Agency (CISA) and the Federal Bureau of Investigation (FBI).
US officials identified the Russian hacker group as Energetic Bear, a codename used by the cybersecurity industry. Other names for the same group also include TEMP.Isotope, Berserk Bear, TeamSpy, Dragonfly, Havex, Crouching Yeti, and Koala.
Officials said the group has been targeting dozens of US state, local, territorial, and tribal (SLTT) government networks since at least February 2020.
Companies in the aviation industry were also targeted, CISA and FBI said.
The two agencies said Energetic Bear "successfully compromised network infrastructure, and as of October 1, 2020, exfiltrated data from at least two victim servers." [emphasis ZDNet]
The intrusions detailed in today's CISA and FBI advisory are a continuation of attacks detailed in a previous CISA and FBI joint alert, dated October 9. The previous advisory described how hackers had breached US government networks by combining VPN appliances and Windows bugs.
Today's advisory attributes those intrusions to the Russian hacker group but also provides additional details about Energetic Bear's tactics.
To move laterally across compromised networks, CISA and the FBI said the Russian hackers used the Zerologon vulnerability in Windows Servers (CVE-2020-1472) to access and steal Windows Active Directory (AD) credentials. The group then used these credentials to roam through a target's internal network.
In situations where the attacks succeeded, CISA and the FBI said the hackers moved to steal files from government networks. Based on the information they received, the two agencies said Energetic Bear exfiltrated:
Sensitive network configurations and passwords.
Standard operating procedures (SOP), such as enrolling in multi-factor authentication (MFA).
IT instructions, such as requesting password resets.
Vendors and purchasing information.
Printing access badges.
"To date, the FBI and CISA have no information to indicate this APT actor has intentionally disrupted any aviation, education, elections, or government operations. However, the actor may be seeking access to obtain future disruption options, to influence US policies and actions, or to delegitimize SLTT government entities," the two agencies said.
"As this recent malicious activity has been directed at SLTT government networks, there may be some risk to elections information housed on SLTT government networks. However, the FBI and CISA have no evidence to date that integrity of elections data has been compromised," the two added.
News publication Cyberscoop first reported on Monday that Energetic Bear (TEMP.Isotope) was the hacker group behind the breaches reported in the first CISA and FBI alert.