One of the most topical issues in the field of cybersecurity is a steady increasing numbers of successful social engineering attacks. For assessment of information system, users require the ability to assess of the intensity of user communications in social networks. However, this information is a set of linguistic variables and requires quantification. The purpose of this article is to propose approach to assignment of model parameters for estimates of the probability of multiway social engineering attack. To achieve this goal, the three different modifications of the method by Khovanov were proposed. The modifications are based on the assumption that experts could not only rank the linguistic variables, but give it rough estimates, thereby considerably empower for following quantification. Theoretical relevance of the research is a new approach to getting probability estimates from non-numeric information. Practical relevance of the research is to building a foundation for following use on the evaluation of the probability of propagation of multiway social engineering attacks and analysis of the social graph of organization employees. Thereby we lay the basis of subsequent diagnostics of information systems to identify vulnerabilities to social engineering attacks, as well as to solve social computing problems.