### Summary
A persistent backdoor has been established by the threat actors, allowing them ongoing access to compromised systems. This backdoor is likely a result of prior suspicious sFTP activity.

### Technical Details
- Backdoor appears to be a custom-built malware, designed to evade standard detection mechanisms.
- Command and control (C&C) communication channels identified, indicating ongoing coordination with external servers.

### Next Steps
- **Conduct a comprehensive malware analysis** to understand the backdoor's functionality and remove it.
- **Enhance network monitoring** to detect unusual outbound traffic indicative of lateral movement attempts.
- Implement **network segmentation** to limit potential lateral movement within the organization.