When you're facing some suspicious files while performing forensic investigations or analyzing malware components, it's always interesting to know these files are legit or malicious/modified. One of the key sources to verify hashes is provided by NIST and is called the NSLR project ("National Software Reference Library")[1]. They build "Reference Data Set" (RDS) of information that can be queried to verify a file hash. These RDS are available to download[2] but, as you may expect, there are huge (they are provided as ISO files between 500MB to 4GB!)