YARA Matches

When BinaryAlert finds a file that matches at least one YARA rule, it will save the match information to a DynamoDB table and send an alert to the NAME_PREFIX_binaryalert_yara_matches SNS topic (if it hasn’t already).

DynamoDB Records

All YARA matches are saved to a DynamoDB table. The table has two primary keys, AnalyzerVersion and SHA256. This makes it easy to find every match associated with a given file or, conversely, to find all matches from a specific version of your BinaryAlert deployment.

A manage.py live_test will show you an example of the match record stored in the DynamoDB table:

{
    'AnalyzerVersion': Decimal('1'),
    'MD5': 'FILE_MD5',
    'MatchedRules': {'public/eicar.yara:eicar_av_test'},
    'S3LastModified': '2017-09-16 00:25:37+00:00',
    'S3Metadata': {'filepath': 'eicar_test_UUID.txt'},
    'S3Objects': {'S3:NAME.PREFIX.binaryalert-binaries.REGION:eicar_test_UUID.txt'},
    'SHA256': 'FILE_SHA256'
}

SNS Match Alerts

In addition to saving the DynamoDB record, an alert is sent to the NAME_PREFIX_binaryalert_yara_matches SNS topic when one of the following conditions apply:

  1. The file matches a YARA rule that was not matched in the previous version of the BinaryAlert analyzers, OR
  2. A new S3 object appears which is identical to an already matched binary.

Without these conditions, an alert would trigger for every match in every retroactive analysis. Instead, an alert triggers only when there is a new match.

Note

You must add an SNS subscription in order to receive YARA match alerts.