wiredmikey writes "Norwegian browser maker Opera Software has confirmed that a targeted internal network infrastructure attack led to the theft of a code signing certificate that was used to sign malware. 'The current evidence suggests a limited impact. The attackers were able to obtain at least one old and expired Opera code signing certificate, which they have used to sign some malware. This has allowed them to distribute malicious software which incorrectly appears to have been published by Opera Software, or appears to be the Opera browser,' Opera warned in a brief advisory. The Opera breach signals a growing shift by organized hacking groups to target the internal infrastructure network at big companies that provide client side software to millions of end users."