Patent ID: 7721334

Claim:
A processor-readable medium comprising processor-executable instructions for: parsing an input file to recognize a file format of the input file, wherein the parsing repeatedly parses once with each of a plurality of component parsers contained within a compound parser, wherein each of the plurality of component parsers is configured for recognition of a specific file format by which an input file is configured, wherein the compound parser is extensible, and wherein extending the compound parser comprises adding an additional component parser configured to recognize an additional file format and executable code if present in a file of the additional file format; checking contents of the input file, according to the recognized file format, to determine whether executable code exists within the input file, wherein the executable code determined to exist comprises both executable statements currently known, and not currently known, to be malicious code, and wherein the checking comprises detecting executable code because its location within the input file is inconsistent with the recognized file format; continuing to parse the input file until a component parser recognizes the file format of the input file or until all available component parsers within the compound parser have parsed the input file; and sending a status in response to results of said checking, wherein sending a status comprises further instructions for: sending a file-has-no-code status when the file format of the input file was recognized and no executable code was found; sending a file-has-code status when executable code was found; and sending a don't-know status when the file format of the input file was not recognized; wherein adding an additional component parser comprises instructions for: identifying a new file format, wherein ability to recognize the new file format is functionality to be extended to the compound parser; configuring a new component parser according to the new file format, wherein the new component parser is configured to recognize files of the new format and also to recognize executable code in files of the new format by locating executable code that is inconsistent with the new file format; and extending functionality of the compound parser by adding the new component parser to the compound parser.