Trend Micro Threat Research observed active exploitation of the Spring4Shell vulnerability assigned as CVE-2022-22965, which allows malicious actors to weaponize and execute the Mirai botnet malware. The exploitation allows threat actors to download the Mirai sample to the “/tmp” folder and execute them after permission change using “chmod”.

We began seeing malicious activities at the start of April 2022. We also found the malware file server with other variants of the sample for different CPU architectures.

We discuss our findings and analysis of the exploits and patch based on our samples, as well as real-world application of the potential risks in this blog. In the last section, we include some recommendations on how to mitigate these risks.