Small Web Format (SWF) or Flash files are widely used on the Internet to provide Rich Internet Applications (RIAs). This makes SWF files an excellent candidate for disseminating hidden data. However, digital forensic investigators are unable to detect and extract the hidden data because limited information is available about the techniques used to hide data in SWF files. This paper investigates several data insertion techniques for hiding data in SWF files. The techniques include appending data to an SWF file, adding an extra Metadata tag, creating a custom Definition tag, and replacing fill bits with hidden data. Experimental results obtained with a simple SWF (version 10) file are used to evaluate the effectiveness of the data hiding techniques and identify the artifacts that remain.