BlackCat ransomware gang targets unpatched Microsoft Exchange Server to exploit vulnerabilities and to gain access to targeted networks.

According to the Microsoft 365 Defender Threat Intelligence Team, the attackers, after gaining an entry point, carried out a number of actions, including gathering information about the compromised machines, carrying out credentials thefts and lateral movement activities.

After carrying out the above actions, the attackers then went to harvest intellectual property, while dropping the ransomware payload.

In their analysis, the researchers pointed out how no two BlackCat ‘lives’ or deployment might look the same.

“In another incident we observed, we found that a ransomware affiliate gained initial access to the environment via an internet-facing Remote Desktop server using compromised credentials to sign in,” the researchers said.

Giving further details, Microsoft said that “two of the most prolific” affiliate threat groups associated with several ransomware families such as Hive, Conti, REvil and LockBit 2.0 are now spreading BlackCat.

“Detecting threats like BlackCat, while good, is no longer enough as human-operated ransomware continues to grow, evolve and adapt to the networks they’re deployed on the attackers they work for. These types or attacks continue to take advantage of an organization’s poor credential hygiene and legacy configurations or misconfigurations to succeed,” the researchers said.