You can view the documentation below, or browse our GitHub Repository, where you can contribute to FAQ Documents. For complete documentation, download the ClamAV Manual.

Signatures based on container metadata

ClamAV 0.96 allows creating generic signatures matching files stored inside different container types which meet specific conditions. The signature format is:


where the corresponding fields are:

  • VirusName: Virus name to be displayed when signature matches.

  • ContainerType: The file type containing the target file. For example:
    • CL_TYPE_ZIP,
    • CL_TYPE_RAR,
    • CL_TYPE_ARJ,
    • CL_TYPE_7Z,

    Use * as a wild card to indicate that container type may be any file type. For a full list of ClamAV file types, see the ClamAV File Types Reference.

  • ContainerSize: size of the container file itself (eg. size of the zip archive) specified in bytes as absolute value or range x-y.

  • FileNameREGEX: regular expression describing name of the target file

  • FileSizeInContainer: usually compressed size; for MAIL, TAR and CPIO == FileSizeReal; specified in bytes as absolute value or range.

  • FileSizeReal: usually uncompressed size; for MAIL, TAR and CPIO == FileSizeInContainer; absolute value or range.

  • IsEncrypted: 1 if the target file is encrypted, 0 if it’s not and * to ignore

  • FilePos: file position in container (counting from 1); absolute value or range.

  • Res1: when ContainerType is CL_TYPE_ZIP or CL_TYPE_RAR this field is treated as a CRC sum of the target file specified in hexadecimal format; for other container types it’s ignored.

  • Res2: not used as of ClamAV 0.96.

The signatures for container files are stored inside .cdb files.