Cybersecurity threats have become increasingly prevalent in financial systems across East Africa, with South Sudan experiencing significant vulnerabilities. A systematic search of peer-reviewed journals, books, and reports was conducted using databases such as Scopus and Google Scholar. Keywords included 'cybersecurity', 'financial systems', and 'South Sudan'. The review identified a notable increase in cybersecurity incidents targeting financial institutions in South Sudan over the study period. Mitigation strategies, including enhanced security protocols and regular training for staff, were found to be insufficiently implemented by most financial entities. Financial regulators should mandate more stringent cybersecurity measures and provide guidelines on best practices. Financial institutions need to invest in advanced threat detection technologies. Model estimation used $\hat{\theta}=argmin_{\theta}\sum_i\ell(y_i,f_\theta(x_i))+\lambda\lVert\theta\rVert_2^2$, with performance evaluated using out-of-sample error.