On March 2nd, zero-day vulnerabilities affecting Microsoft Exchange were publicly disclosed. These vulnerabilities are being actively exploited in the wild by HAFNIUM, a threat actor believed to be a nation state.
What is HAFNIUM?
According to a CISA alert:
Microsoft has released out-of-band security updates to address vulnerabilities affecting Microsoft Exchange Server 2013, 2016, and 2019. A remote attacker can exploit three remote code execution vulnerabilities—CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065—to take control of an affected system and can exploit one vulnerability—CVE-2021-26855—to obtain access to sensitive information. These vulnerabilities are being actively exploited in the wild.
CISA also issued an emergency directive urging organizations to patch on-premises Exchange Servers and search their networks for indicators of attack.
For more details about HAFNIUM, and advice on how you should respond, watch this video from Mat Gangwer, the head of the Sophos Managed Threat Response (MTR) team.
How Sophos Managed Threat Response (MTR) can help
Threat such as HAFNIUM are a great example of the peace of mind you get knowing your organization is backed by an elite team of threat hunters and response experts.
When the HAFNIUM news broke, the Sophos MTR team immediately began to hunt and investigate in customer environments to determine if there was any activity related to the attack. Additionally, they also looked to uncover any new artifacts or IoCs related to the attack that could provide further protection for all Sophos customers.
The 24/7 nature of Sophos MTR meant that not a single second was wasted before the team got to work, ensuring our customers were protected.
SophosLabs has also published detections related to the known activity and IOCs related to the Exchange vulnerability. This is in addition to previous protections already in place to detect post-exploit activity.
Concerned about HAFNIUM? Contact Sophos MTR today to ensure that any potential adversarial activity in your environment is identified and neutralized.