Software Security Patch Management -- A Systematic Literature Review of Challenges, Approaches, Tools and Practices

Context: Software security patch management purports to support the process of patching known software security vulnerabilities. Given the increasing recognition of the importance of software security patch management, it is important and timely to systematically review and synthesise the relevant literature on this topic. Objective: This paper aims at systematically reviewing the state of the art of software security patch management to identify the socio-technical challenges in this regard, reported solutions (i.e., approaches, tools, and practices), the rigour of the evaluation and the industrial relevance of the reported solutions, and to identify the gaps for future research. Method: We conducted a systematic literature review of 72 studies published from 2002 to March 2020, with extended coverage until September 2020 through forward snowballing. Results: We identify 14 socio-technical challenges, 18 solution approaches, tools and practices mapped onto the software security patch management process. We provide a mapping between the solutions and challenges to enable a reader to obtain a holistic overview of the gap areas. The findings also reveal that only 20.8% of the reported solutions have been rigorously evaluated in industrial settings. Conclusion: Our results reveal that 50% of the common challenges have not been directly addressed in the solutions and that most of them (38.9%) address the challenges in one phase of the process, namely vulnerability scanning, assessment and prioritisation. Based on the results that highlight the important concerns in software security patch management and the lack of solutions, we recommend a list of future research directions. This study also provides useful insights about different opportunities for practitioners to adopt new solutions and understand the variations of their practical utility.