### Overview
Following the remote code execution via malicious PDFs, analysis indicates that **APT1** employs sophisticated PDF exploits targeting vulnerabilities in outdated PDF readers.

### Tactics
- **Exploitation**: PDFs are designed to exploit specific vulnerabilities (e.g., CVE-XXXX-XXXX).
- **Payload Delivery**: Upon execution, the payload establishes initial foothold and downloads additional malware.

### Recommendations
- Ensure all PDF reader software is updated to the latest versions.
- Implement strict file type restrictions and scanning protocols on email attachments.

### Next Steps
Monitor for **Persistence** mechanisms, as APT1 often alters system registries to maintain access.