I was wondering how secure are the file shredding software and free space wipers?
Lets say we are using PC Windows, and software CCleaner (from piriform) or File Shredder (found here) to securely delete our files or wipe our free disk space. We assume that the software is downloaded from the developer's sites.
I know I might thinking too negatively, but while those software are securely deleting the files or wiping free disk space, is there any chance for those programs to collect information of the deleted files, for example by making small screenshots of our data or compressed copies of the txt files, documents, passwords, or jpg or videos files and transmit to an external IP through the internet?
Even though unplugging the ethernet internet cable or use the firewall to block those programs to send any data over internet while the deleting process happens, isn't there any possibility for the software to copy all our deleted files to another position of our hard disks, hidden from us, and transmit them slowly and at random times when the software traces that we are back online?
They know that we are using that kind of software for deleting confidential files, so they might be after our data. I am considering to wipe the free disk space of my hard disk drives, but I am really not sure if CCleaner or File Shredder are really 100% secure. CCleaner is closer to my selection, but for some reason it sees my external USB drives as SSD, and can perform only one pass of free space wipe. I am using the portable version of CCleaner.
File shredder is a bit more suspicious to me, since the developer company site doesn't have an email or the firm is not well known. But I might be wrong.
Also which free disk space wiper are you using and do you feel 100% secure and safe when wiping free space or shredding your files?