Abstract: Disclosed herein are systems and methods for detecting cyclic activity in an event stream. In one aspect, an exemplary method comprises, creating a buffer, determining a threshold for indicating a beginning of a cycle, processing each event by filling the buffer with the event, determining a number of unique events in the buffer, when the number reaches a predetermined size of the buffer, replacing one event with another by excluding the earliest event and including the new event, recalculating the number of unique events, comparing the recalculated number with a threshold for a maximum number of unique events for cycle detection, detecting a beginning of a cycle when the number of unique events is less than or equal to the maximum number of unique events for cycle detection, excluding further events from the event stream, and continuing to recalculate the number of unique events after each addition.

Abstract: Disclosed herein are systems and methods for detecting harmful scripts. In one aspect, an exemplary method comprises, identifying a file containing a script, wherein the identification of the file is performed by analyzing each file of a plurality of files for a presence of a harmful script, generating a summary of the script based on the identified file, calculating static and dynamic parameters of the generated summary of the script, recognizing a script programming language based on the calculated static parameters and dynamic parameters of the generated summary of the script using at least one language recognition rule, processing the identified file based on the data about the recognized script programming language, generating a set of hash codes based on a processed file using rules for generating hash codes, and detecting the harmful script when the generated set of hash codes is similar to known harmful sets of hash codes.

Abstract: Disclosed herein are systems and methods for modifying execution environments of applications. In one aspect, an exemplary method comprises, identifying an application that requires an isolated execution environment in order to be analyzed, generating an isolated execution environment to launch the identified application using constraint generating rules from a rules database, launching the application in the isolated execution environment that was generated, when an incorrect execution of the application is detected after the application is launched in the isolated execution environment, stopping the execution of the application and modifying the isolated execution environment using the constraint generating rules from the rule database, and when an incorrect execution of the application is not detected after the application is launched in the isolated execution environment, checking for a presence of a malicious code in the application running in the modified isolated execution environment.

Abstract: Disclosed is a method for analyzing a log for conducting an antivirus scan of a file. The method includes opening a file in a virtual machine. The opening of the file includes execution of a guest process having a thread in a virtual processor of the virtual machine. A plurality of events in the thread of the guest process is intercepted. Registers associated with a system call made during execution of the first thread of the guest process are determined. Execution of the thread of the guest process is halted. In a log associated with the opening of the file, information is saved indicating events intercepted during execution of the thread in an altered guest physical memory page, and context data of the virtual processor. Using at least one template having rules, the saved log is analyzed to determine whether the file opened in the virtual machine is harmful.

Abstract: Disclosed are systems and methods for analysis of files for maliciousness and determining an action. An exemplary method comprises: opening a file, by a processor, in a virtual machine, intercepting an event arising in an execution of a thread of a process created upon opening of the file, determining, a context of the processor on which the thread is being executed, the determination including reading register values of the processor and a stack, comparing the context with rules that check: a behavior of the thread of the process, a changing, by the thread, of attributes of the file, and an access of the thread to the Internet, and based on a result of the comparison, performing at least one of: recognizing the file as being malicious, halting the execution of the thread, changing the context of the processor, and waiting for a next intercepted event.

Abstract: Disclosed is a method for analyzing a log for conducting an antivirus scan of a file. The method includes opening a file in a virtual machine. The opening of the file includes execution of a guest process having a thread in a virtual processor of the virtual machine. A plurality of events in the thread of the guest process is intercepted. Registers associated with a system call made during execution of the first thread of the guest process are determined. Execution of the thread of the guest process is halted. In a log associated with the opening of the file, information is saved indicating events intercepted during execution of the thread in an altered guest physical memory page, and context data of the virtual processor. Using at least one template having rules, the saved log is analyzed to determine whether the file opened in the virtual machine is harmful.

Abstract: Disclosed are systems and methods for generating a log for conducting an antivirus scan of a file. The described technique includes opening a file in a virtual machine, which causes execution of a guest process and a thread in a (virtual) processor of the virtual machine. The technique includes identifying, during execution of the first thread, events that involve alteration of guest physical memory pages of the virtual machine. The technique determines altered guest physical memory page based on analysis of the log and identifies when a transfer of control to altered guest physical memory pages has occurred. The resultant log for analysis by a security application includes information indicating the events occurring during execution of the thread in the altered guest physical memory page, and context data of the virtual processor on which the thread is being executed.

Abstract: Disclosed are system and method for detecting malicious code in files. One exemplary method comprises: intercepting, by a processor, one or more application program interface (API) calls during an execution of a process launched from a file of a computing device; determining and detecting, by the processor, a presence of an exit condition of the process; in response to detecting the exit condition, identifying one or more signatures of a first type and transferring one or more saved memory dumps of the computing device to an emulator for execution; and determining and identifying a malicious code in the file in response to detecting one or more signatures of a second type based at least upon execution results of the transferred memory dumps of the computing device.

Abstract: Disclosed are systems and methods for analysis of files for maliciousness and determining an action. An exemplary method comprises: opening a file, by a processor, in a virtual machine, intercepting an event arising in an execution of a thread of a process created upon opening of the file, determining, a context of the processor on which the thread is being executed, the determination including reading register values of the processor and a stack, comparing the context with rules that check: a behavior of the thread of the process, a changing, by the thread, of attributes of the file, and an access of the thread to the Internet, and based on a result of the comparison, performing at least one of: recognizing the file as being malicious, halting the execution of the thread, changing the context of the processor, and waiting for a next intercepted event.

Abstract: Disclosed are systems and methods of analysis of files for maliciousness in a virtual machine. An exemplary method comprises: opening and executing a file by a processor in a virtual machine; intercepting an event arising in the process of execution of a thread of a process created upon opening of the file; halting the execution of the thread; reading the context of the processor on which the thread is being executed; comparing the context of the processor with one or more rules; and based on the results of the comparison, performing at least one of: recognizing the file as being malicious; halting the execution of the process created upon opening of the file; changing the context of the processor; and waiting for the next intercepted event.

Abstract: Disclosed are systems and methods for generating a log for conducting an antivirus scan of a file. The described technique includes opening a file in a virtual machine, which causes execution of a guest process and a thread in a (virtual) processor of the virtual machine. The technique includes identifying, during execution of the first thread, events that involve alteration of guest physical memory pages of the virtual machine. The technique determines altered guest physical memory page based on analysis of the log and identifies when a transfer of control to altered guest physical memory pages has occurred. The resultant log for analysis by a security application includes information indicating the events occurring during execution of the thread in the altered guest physical memory page, and context data of the virtual processor on which the thread is being executed.

Abstract: Disclosed are systems and methods of analysis of files for maliciousness in a virtual machine. An exemplary method comprises: opening and executing a file by a processor in a virtual machine; intercepting an event arising in the process of execution of a thread of a process created upon opening of the file; halting the execution of the thread; reading the context of the processor on which the thread is being executed; comparing the context of the processor with one or more rules; and based on the results of the comparison, performing at least one of: recognizing the file as being malicious; halting the execution of the process created upon opening of the file; changing the context of the processor; and waiting for the next intercepted event.

Abstract: Disclosed are system and method for detecting malicious code in files. One exemplary method comprises: intercepting, by a processor, one or more application program interface (API) calls during an execution of a process launched from a file of a computing device; determining and detecting, by the processor, a presence of an exit condition of the process; in response to detecting the exit condition, identifying one or more signatures of a first type and transferring one or more saved memory dumps of the computing device to an emulator for execution; and determining and identifying a malicious code in the file in response to detecting one or more signatures of a second type based at least upon execution results of the transferred memory dumps of the computing device.

Abstract: A method and system are provided for performing an antivirus scan of a file on a virtual machine. An example method includes performing a first execution of the file on the virtual machine, recording a first log that includes an API function call and an internal event detected during execution, and determining if any signatures in the log are stored in a signatures database. Moreover, if no signatures in the first log are found in the first database of signatures, the file is classified as not malicious. In contrast, if at least one signature is found, a second execution of the file is perform and a second log is recorded that includes a detected internal event. Moreover, the method includes determining if any signatures in the second log are stored in a second database of signatures; and classifying the file as not malicious if no signatures are found.