Security researchers have uncovered a malicious campaign that relies on a valid code-signing certificate to disguise malicious code as legitimate executables. The threat actor behind Blister malware has been running campaigns for at least three months, since at least September 15, security researchers from Elastic search company found. Using valid certificates to sign malware is an old trick that threat actors learned years ago, they used to steal certificates from legitimate companies. Being signed with a valid certificate and deployed with administrator privileges makes Blister slip past security solutions.”]