Over in the Comodo forums their finding that malware is using signed signature (digital signature, trusted vendors, whitelist etc) to bypass security.
Is avast vulnerable aswell?
stevejrc Avast has a different kind of method compare to Comodo so I wouldn’t worried to much because Avast has perform better in the AV detection rate, my comodo firewall setup ‘Automatically trust files from trust installer’ has been untick & also ‘Create rules for safe applications’ been ticked.
You’re in safe hands with Avast 
Comodo needs to rely to digital signatures to reduce the popups of their “deny all” policy.
I thought avasts persistent caching checks for valid certificates aswell?
No, this doesn’t affect us in any way, at least in v5.0…
It does have some implications for the new Behav Shield / auto-sandbox modules in v5.1/6.0, but we were anticipating such issues so it’s not a big deal…
What does Comodo do to define a trusted vendor? It should be restricted to those with a valid level 3 digital certificate. Less than that represents an unacceptable security risk, since anyone can get a lesser encryption key and sign stuff. Or do they trust anyone who buys or gets a free certificate from them?
Why don’t you ask in their forums? 
Please, post back a link for us to learn.
+1