A new strain of malware began infecting computer systems across the globe on Tuesday.  Similar to the WannaCry ransomware that struck last month, the malware used in this week’s attack spreads quickly across multiple computers on a network, encrypting files and displaying a ransom note that requests $300 worth of bitcoin for a decryption key.

Reports of infection began in Ukraine, where computer systems belonging to government ministries, financial institutions, transportation systems, and major energy companies began malfunctioning.  The attack was first believed to be caused by a variant of the “Petya” strain of ransomware, however recent reports from security experts indicate that the malware used during this week’s attack was altered so that, even with a decryption key, encrypted files cannot be recovered.  This fact has lead several sources to dub the malware “ExPetr” and speculate that the attacker’s motivations were destructive instead of financial.

In this post, we summarize key facts regarding the WannaCry ransomware attack, provide an abbreviated list of known affected companies, and offer an overview of the legal issues and the response to the attack. This post is an update to our prior coverage of WannaCry.