A. Relying solely on VirusTotal for file hash lookups and URL reputation checks to block known indicators of compromise (IOCs).

B. Submitting all suspicious email attachments to WildFire for immediate dynamic analysis and automated signature generation, while simultaneously cross- referencing campaign details and adversary profiles from Unit 42 research reports.

C. Configuring email gateways to block all attachments with a '.exe' extension, regardless of their content or origin.

D. Developing custom YARA rules based on open-source intelligence on similar campaigns and applying them to all inbound email traffic without further analysis.

E. Implementing strict egress filtering to prevent any outbound connections on non-standard ports, which will implicitly block all C2 traffic.