Tag Archives: threat analysis

Avast

Locky’s JavaScript downloader

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Locky is a considerable security threat that is now widely spread.

It seems that Locky’s authors are now predominately using one campaign to spread the ransomware. Last week, we published a blog post about Locky Ransomware, the ransomware that is most likely being spread by the infamous Dridex botnet. In our last blog post, we described three campaigns the Locky authors are using to spread their malware. Now Locky’s authors are mainly using the campaign with javascript packed into a zip file sent to people through phishing emails.

Avast

A closer look at the Locky ransomware

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Today, we bring you a deep look into the latest ransomware called Locky. This new file encryptor, targeting PC users, has most likely been created by authors of the well-known Dridex botnet and is spread the same way.

Locky uses all “top class” features, such as a domain generation algorithm, custom encrypted communication, TOR/BitCoin payment, strong RSA-2048+AES-128 file encryption and can encrypt over 160 different file types, including virtual disks, source codes and databases.

We monitored the Locky family this past month and discovered a second variant of the malware, which has new features and program code improvements. Locky’s authors added a new hard-coded seed to the domain generation algorithm, which allows them to deactivate Locky on Russian PCs.

Infection vector

Locky is spreading via spam email campaigns that are similar to those used by the Dridex botnet. They use similar file names, obfuscation, email content and structure of download URLs.

We have observed three different campaign versions of Locky and have described them below.

Below is an example of one of the spam emails. The emails are designed to make people believe they were sent from large companies such as Nordstrom, Symantec and Crown Holdings.