Chester Wisniewski, Principal Research Scientist, Sophos on Bad Rabbit

“It was only a matter of time before someone took the ideas from WannaCry and NotPetya and ran with them for another go at unsuspecting victims. It appears this latest variation, the so-called Bad Rabbit ransomware, is being distributed via a fake Adobe Flash Player installer file. Initial reports are primarily from Eastern Europe, especially focused on Russia and Ukraine. What makes this malware more dangerous than your typical ransomware being distributed in a similar manner is its ability to spread across an organization as a worm and not just through email attachments or vulnerable web plugins. It is rumored to contain the same password stealing and spreading mechanism as NotPetya, allowing it to traverse an enterprise and cripple it in no time.

SophosLabs are working to confirm these details, but have already ensured protection for Sophos customers. At the moment Sophos Anti-Virus customers will detect this variation as Troj/Ransom-ERK. Sophos Sandstorm proactively detected this threat through our machine learning detection as well as Sophos Intercept X blocking this threat through the use of our CryptoGuard technology. Sophos web protection products are also blocking known distribution points. We will publish further details as they are known.

In addition, Sophos recommends the following:

• Keep software up to date with the latest patches.
• Back up regularly and keep a recent backup copy off-site. There are dozens of ways other than ransomware that files can suddenly vanish, such as fire, flood, theft, a dropped laptop or even an accidental delete.
• Encrypt your backup and you won’t have to worry about the backup device falling into the wrong hands.
• Defense-in-depth is your friend. Criminals constantly try to outwit security products, having many layers of protection helps bridge the gap when one is evaded.
• Download the free trial of Sophos Intercept X and, for home (non-business) users, register for the free Sophos Home Premium Beta, which prevents ransomware by blocking the unauthorized encryption of files and sectors on your hard disk.”