Abstract: Systems and methods for performing a repeat antivirus scan of a file are disclosed. A local database is saved on a mobile device, where each record is added to the database when the corresponding file is recognized as being non-malicious as a result of an antivirus scan. A short hash sum of the file is computed and the long hash sum of the file and information about the antivirus scan performed and corresponding to the first hash sum of the file are found in the aforementioned database. Using the long hash sum, a verdict on the file is requested from the cloud services. An antivirus scan of the file is performed, except when the verdict obtained is unchanged (as compared to the verdict contained in the information about the antivirus scan performed of the obtained record corresponding to the file), and no updating of the antivirus databases has occurred since the date of performing the antivirus scan.

Abstract: Systems and methods for performing a repeat antivirus scan of a file are disclosed. A local database is saved on a mobile device, where each record is added to the database when the corresponding file is recognized as being non-malicious as a result of an antivirus scan. A short hash sum of the file is computed and the long hash sum of the file and information about the antivirus scan performed and corresponding to the first hash sum of the file are found in the aforementioned database. Using the long hash sum, a verdict on the file is requested from the cloud services. An antivirus scan of the file is performed, except when the verdict obtained is unchanged (as compared to the verdict contained in the information about the antivirus scan performed of the obtained record corresponding to the file), and no updating of the antivirus databases has occurred since the date of performing the antivirus scan.

Abstract: Disclosed are system, method and computer program product for detecting malicious files on mobile devices. An example method includes: analyzing a file to identify classes and methods contained in said classes; identifying a bytecode array for each identified method; determining instructions contained in each method by identifying a corresponding operation code from the bytecode array of each method; dividing the determined instructions for each method into a plurality of groups based on similarity of functionality among said instructions; forming a vector for each method on the basis of the results of the division of the instructions into the plurality of groups; comparing the formed vectors with a plurality of vectors of known malicious files to determine a degree of similarity between the compared vectors; and determining whether the analyzed file is malicious or clean based on the degree of similarity between the compared vectors.

Abstract: Disclosed are system, method and computer program product for detecting malicious files on mobile devices. An example method includes: analyzing a file to identify classes and methods contained in said classes; identifying a bytecode array for each identified method; determining instructions contained in each method by identifying a corresponding operation code from the bytecode array of each method; dividing the determined instructions for each method into a plurality of groups based on similarity of functionality among said instructions; forming a vector for each method on the basis of the results of the division of the instructions into the plurality of groups; comparing the formed vectors with a plurality of vectors of known malicious files to determine a degree of similarity between the compared vectors; and determining whether the analyzed file is malicious or clean based on the degree of similarity between the compared vectors.