After downloaded the Firefox 27.01 version I checked it for virus.
Avast 8.0.1497
Virus definition 140213-1
Released 2014-02-13 19:17:43
Found: Threat:Win32:Malware-gen inside the plugin-container.exe
New: Kanri (Oct 9, '24), Platform 29.5.3 (Jun 27, '24)
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Downloaded a new copy of FirefoxPortable 27.01 from PortableApps and this time Avast did NOT find any malware.
Double checked with latest ClamwinPortable with a virus free result.
First time ever this has happened with software from PortableApps.
Why? No clue...
Be alert. Always.
Best regards.
Steff
Avast's heuristic scanner evidently had a false positive.
See here: https://portableapps.com/support#false_positive