Industrial control systems have been at the center of some scary security stories recently, but investigating malware infections in such environments is not easy because analysts often having a hard time telling suspicious and good files apart.Security researchers have identified two malware campaigns this year that targeted SCADA (supervisory control and data acquisition) systems -- Havex and BlackEnergy. Such attacks are expected to grow in number, as new reports show that state-sponsored hackers are increasingly interested in critical infrastructure companies.Now, a newly launched service called WhiteScope provides industrial control system owners and investigators with a list of good files from SCADA products and related software. The "whitelist" can be used to pin down potentially suspicious files when investigating possible compromises."While participating in a few incident response engagements, I realized it's fairly difficult to know what is a 'legitimate' ICS\/SCADA file and what is not," Billy Rios, the security researcher who created the new service, said on the WhiteScope site. "Given the overwhelming majority of ICS\/SCADA vendors refuse to sign their software, we're stuck with determining whether files like 'FTShell.dll' or 'WFCU.exe' (both legitimate files by the way) are really supposed to be there."Rios, who has worked for Microsoft and Google in the past, but is also known for his independent SCADA security research, has collected "known good" file artifacts like file hashes, registry changes, processes, and loaded modules for ICS\/SCADA software from installation media, as well as live running systems.The WhiteScope database that he created currently contains 346,458 files that correspond to over 80 SCADA and ICS product versions from a large number of vendors including General Electric, Schneider Electric, Rockwell Automation, Siemens and Advantech.For now the service allows users to submit a file or a file hash through a Web form on www.icswhitelist.com to check it against those in the database. However, Rios is working on an application programming interface (API) that will allow users to submit and check multiple files and hashes at once."A 'hit' in the database indicates that the hash\/file you've submitted was previously seen within an ICS\/SCADA installation," Rios said. "A 'miss' simply indicates that WhiteScope hasn't previously seen that file before. I would first check to see if the file is signed. If the file is not signed (likely the case for ICS\/SCADA), check the 'supported products' page and see if the product you are looking at is in our product list. If the product is not in the list, please consider working with us to get a good set of hashes for that product. If the product is in the product list and the file doesn't match anything we have, I would start an investigation on that file."The researcher is also working on creating a firmware database, as well as a similar whitelist for medical device software, which is also typically not signed and can't easily be verified.