This paper focuses on evaluating the security challenges faced by mobile field hospitals, which play a crucial role in emergency response and disaster management in remote and austere environments. The authors conducted a penetration test using the Open Source Security Testing Methodology Manual (OSSTMM) framework to assess the security posture of a mobile field hospital. The methodology employed in the study included a combination of automated and manual techniques such as network scanning, vulnerability assessments, social engineering, and exploitation. The penetration test revealed several security vulnerabilities in the mobile field hospital, including weak passwords, unpatched software, and inadequate network segmentation. Additionally, the study identified vulnerabilities in the hospital's medical devices and equipment, posing a risk of cyber-attacks that could disrupt operations and compromise patient safety. The results underscore the importance of implementing enhanced security measures in mobile field hospitals to mitigate cyber threats and ensure the uninterrupted functioning of medical operations during emergencies and disasters. This study provides a comprehensive analysis of the mobile field hospital's security posture using the OSSTMM framework and emphasizes the urgent need for improved security practices in such settings.