Microsoft Says China-Linked Hackers Abused Azure in Attacks

Microsoft Reports Evolution of China-Linked Threat Actor GADOLINIUM

Microsoft this week announced that it recently removed 18 Azure Active Directory applications that were being abused by China-linked state-sponsored threat actor GADOLINIUM.

Also known as APT40, TEMP.Periscope, TEMP.Jumper, Leviathan, BRONZE MOHAWK, and Kryptonite Panda, the adversary has been active since at least 2013, mainly operating in support of China’s naval modernization efforts, through targeting various engineering and maritime entities, including a U.K.-based company.

The threat actor was recently observed leveraging Azure cloud services and open source tools in attacks employing spear-phishing emails with malicious attachments.

“As these attacks were detected, Microsoft took proactive steps to prevent attackers from using our cloud infrastructure to execute their attacks and suspended 18 Azure Active Directory applications that we determined to be part of their malicious command & control infrastructure,” the tech company says.

According to Microsoft, GADOLINIUM has expanded its target list to include the Asia-Pacific region, as well as other targets in higher education and regional government organizations. Previously employing custom malware, the threat actor has added open-source tools to their toolset over the past year, making tracking more difficult.

The group has been experimenting with the use of cloud services for years, starting with a Microsoft TechNet profile in 2016. In 2018, the hackers abused GitHub to host commands, and 2019 and 2020 attacks employed similar techniques.

Over the past year, similar to other state-sponsored threat groups, GADOLINIUM has included open-source tools in its portfolio, which also results in lower overall costs for the attackers, in addition to making attribution more difficult.

In April this year, the adversary adopted COVID-19 lures in their spear-phishing emails. The multi-stage infection process would result in a modified version of the open-source PowershellEmpire toolkit being delivered.

The toolkit enables the threat actor to load additional payloads onto the victim’s machine, including a command and control module that leverages OneDrive to execute commands and retrieve results. As part of the attacks, GADOLINIUM leveraged an Azure Active Directory application for data exfiltration to OneDrive.

“From an endpoint or network monitoring perspective the activity initially appears to be related to trusted applications using trusted cloud service APIs and, in this scenario, no OAuth permissions consent prompts occur,” Microsoft explains.

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