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# Allow List Databases

## File Allow Lists

To allow a specific file use the MD5 signature format and place it inside a database file with the extension of `.fp` (for “false positive”). To allow a specific file with the SHA1 or SHA256 file hash signature format, place the signature inside a database file with the extension of `.sfp` (for “SHA false positive”).

To generate FP or SFP signatures, try something like this…

MD5:

    sigtool --md5 /path/to/false/positive/file >> /path/to/databases/false-positives.fp

SHA256:

    sigtool --sha256 /path/to/false/positive/file >> /path/to/databases/false-positives.sfp

Here’s an example adding the EICAR test file to an allow list by generating a sha256 false positive signature:

    ❯ clamscan ~/Downloads/eicar.com
    /mnt/c/Users/micah/Downloads/eicar.com: Win.Test.EICAR_HDB-1 FOUND

    ...

    ❯ sigtool --sha256 ~/Downloads/eicar.com >> /var/lib/clamav/false-positives.sfp

    ❯ clamscan ~/Downloads/eicar.com
    /mnt/c/Users/micah/Downloads/eicar.com: OK
    ...

## Signature Ignore Lists

To ignore a specific signature from the database you just add the signature name into a local file with the `.ign2` extension and store it inside the database directory.

E.g:

    Eicar-Test-Signature

Additionally, you can follow the signature name with the MD5 of the entire database entry for this signature. In such a case, the signature will no longer be ignored when its entry in the database gets modified (eg. the signature gets updated to avoid false alerts). E.g:

    Eicar-Test-Signature:bc356bae4c42f19a3de16e333ba3569c

Historically, signature ignores were added to `.ign` files. This format is still functional, though it has been replaced by the `.ign2` database.

## Phishing Heuristic Allow Lists

ClamAV may alert on suspicious links with alerts along the lines of “`Heuristics.Phishing.Email.SpoofedDomain`”. If you encounter a false positive for this kind of detection, you can create an allow list signature.

Allow list signatures for suspicious HTML links are added to the `.wdb` phishing signature database. Read the Phishing Signature documentation to learn more.