Is "pluginpayloadattachment" an indicator of malware?

Thanks. I did have malware on my Mac and it became almost non-functional. I ran some tools on it to clean it up. Afterwards, I was trying to figure out the source. Two issues were already identified in a malware scan: one was a plugin embedded inside an app that I bought from the App Store. (I'm surprised that this malware made it past Apple.)

The second was a fake version of the Adobe Flash installer. I don't know how it got on my Mac because Flash is already set to auto-update from the Adobe site in my Preference settings. "Get info" showed that the fake Flash installer came from an "amazonaws" server and not from the Adobe site.

I got rid of those files but afterwards, I was looking for any remaining files that had a "last modified" date around the time that I became aware of the malware infection, and "pluginpayloadattachment" was one of them.