9. A system for detecting malware using file clustering, the system comprising: an identification module, stored in memory, that: identifies an unknown file with an unknown reputation; identifies at least one known file with a known reputation that co-occurs with the unknown file; a reputation module, stored in memory, that identifies a classification assigned to the known file; an evaluation module, stored in memory, that determines a probability that the unknown file is of the same classification as the known file; a classification module, stored in memory, that assigns, based on the probability that the unknown file is of the same classification as the known file, the classification of the known file to the unknown file; at least one physical processor configured to execute the identification module, the reputation module, the evaluation module, and the classification module; wherein the identification module identifies the unknown file by: obtaining, from at least one additional client device, information that identifies the unknown file; querying, using the information that identifies the unknown file, a file reputation database that associates file information with file reputations; receiving, in response to querying the file reputation database, an indication that the unknown file's reputation is unknown.
9. A system for detecting malware using file clustering, the system comprising: an identification module, stored in memory, that: identifies an unknown file with an unknown reputation; identifies at least one known file with a known reputation that co-occurs with the unknown file; a reputation module, stored in memory, that identifies a classification assigned to the known file; an evaluation module, stored in memory, that determines a probability that the unknown file is of the same classification as the known file; a classification module, stored in memory, that assigns, based on the probability that the unknown file is of the same classification as the known file, the classification of the known file to the unknown file; at least one physical processor configured to execute the identification module, the reputation module, the evaluation module, and the classification module; wherein the identification module identifies the unknown file by: obtaining, from at least one additional client device, information that identifies the unknown file; querying, using the information that identifies the unknown file, a file reputation database that associates file information with file reputations; receiving, in response to querying the file reputation database, an indication that the unknown file's reputation is unknown. 10. The system of claim 9 , wherein the reputation module identifies the classification assigned to the known file by: querying, using information that identifies the known file, a file reputation database that associates file information with file reputations; receiving, in response to querying the file reputation database, a reputation for the known file that indicates the known file's trustworthiness.