File Format Identification

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File Format Identification is the process of figuring out the format of a sequence of bytes. Operating systems typically do this by file extension or by embedded MIME information. Forensic applications need to identify file types by content.




  • Written in C.
  • Rules in /usr/share/file/magic and compiled at runtime.
  • Powers the Unix “file” command, but you can also call the library directly from a C program.



Forensic Innovations File Investigator TOOLS

  • Proprietary, but free trial available.
  • Available as consumer applications and OEM API.
  • Identifies 3,000+ file types, using multiple methods to maintain high accuracy.
  • Extracts metadata for many of the supported file types.

Stellent/Oracle Outside-In

Forensic Assistant

  • Proprietary.
  • Provides detection of password protected archives, some files of cryptographic programs, Pinch/Zeus binary reports, etc.


Current research papers on the file format identification problem. Most of these papers concern themselves with identifying file format of a few file sectors, rather than an entire file. Please note that this bibliography is in chronological order!

  • Fileprints: identifying file types by n-gram analysis, LiWei-Jen, Wang Ke, Stolfo SJ, Herzog B.., IProceeding of the 2005 IEEE workshop on information assurance, 2005. (Presentation Slides PDF)
  • Douglas J. Hickok, Daine Richard Lesniak, Michael C. Rowe, File Type Detection Technology, 2005 Midwest Instruction and Computing Symposium.(PDF)
  • Gregory A. Hall, Sliding Window Measurement for File Type Identification, Computer Forensics and Intrusion Analysis Group, ManTech Security and Mission Assurance, 2006. (PDF)
  • FORSIGS; Forensic Signature Analysis of the Hard Drive for Multimedia File Fingerprints, John Haggerty and Mark Taylor, IFIP TC11 International Information Security Conference, 2006, Sandton, South Africa.
  • Martin Karresand , Nahid Shahmehri, "Oscar -- Using Byte Pairs to Find File Type and Camera Make of Data Fragments," Annual Workshop on Digital Forensics and Incident Analysis, Pontypridd, Wales, UK, pp.85-94, Springer-Verlag, 2006.
  • Robert F. Erbacher and John Mulholland, "Identification and Localization of Data Types within Large-Scale File Systems," Proceedings of the 2nd International Workshop on Systematic Approaches to Digital Forensic Engineering, Seattle, WA, April 2007.
  • Ryan M. Harris, "Using Artificial Neural Networks for Forensic File Type Identification," Master's Thesis, Purdue University, May 2007. (PDF)
  • Roussev, Vassil, and Garfinkel, Simson, "File Classification Fragment-The Case for Specialized Approaches," Systematic Approaches to Digital Forensics Engineering (IEEE/SADFE 2009), Oakland, California. (PDF)
  • Irfan Ahmed, Kyung-suk Lhee, Hyunjung Shin and ManPyo Hong, Fast File-type Identification, Proceedings of the 25th ACM Symposium on Applied Computing (ACM SAC 2010), ACM, Sierre, Switzerland, March 2010.