Investigation of email-based attack delivering MediaFire ZIP file with execution chain analysis

An investigation revealed a malicious email campaign directing victims to download a ZIP file from MediaFire. The infection chain began with a Python setup executable (Setu.exe) that side-loaded a malicious 400 MB python37.dll containing repeated byte padding. The DLL performed process injection into dllhost.exe, establishing communication with a C2 server at 138.124.186.2:7000. The threat actor deployed three persistence mechanisms: a PowerShell-based path, a fake EdgeUpdate Python executable with scheduled task, and NetSupport RMM as a third access method. The analysis highlights the importance of comparing file timestamps during triage to identify malicious artifacts within compressed archives.

Jul 16, 2026 · unknown severity · unattributed attribution