CryLocker Tries to Hide Its Loot

September 13, 2016 @ 7:30 AM
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2 min read

Trend Micro recently published a report detailing a new kind of ransomware family, dubbed CryLocker, which may also be detected as RANSOM_MILICRY.A.

CryLocker Emerges

This newly discovered ransomware is hardcoded using keyboard layouts specific to certain languages. It does not execute on PCs running languages such as Belarusian, Kazakh, Russian, Sakha, Ukrainian and Uzbek, Softpedia noted.

Everyone else, it seems, is fair game for the criminals behind the malware. The group had previously used the moniker Central Security Treatment Organization, but this changed when they began using the Sundown exploit kit instead of the RIG kit in early September.

The Central Security Treatment Organization name was also used on CryLocker’s Tor-based payment site, which Softpedia noted is now down.

Novel Operations

Bleeping Computer broke down CryLocker’s novel mode of operation in detail. This ransomware, the researchers said, sends information about the victim to the command-and-control server using UDP (port 4444), a mode of transmission uncommon in ransomware.

The malware also leverages public sites, such as Imgur and Pastee, to host victims’ information. Lastly, it queries the Google Maps API to determine the victim’s location using nearby wireless SSIDs.

Trend Micro observed that CryLocker malware uses Portable Network Graphics (PNG) files to package the information harvested from the infected system. Cybercriminals can also use these PNG files to track their victims and update the stolen information over time.

File Abuse

Trend Micro also reported that the malware creates copies of targeted files and encrypts them before deleting the originals. Disk recovery tools can recover the encrypted files, but the file size must be less than 20 MB for most of the tools to work.

Even if you pay the ransom, there’s no guarantee you’ll be able to recover the encrypted files at all: The malware’s unusual approach to file management may not work for you. To make matters worse, the malware family is so young that a decryptor has yet to be developed.

Your best bet is to avoid falling victim altogether by sticking to the well-established best practices for security, avoiding malvertising and phishing schemes as much as possible.

Larry Loeb
Principal, PBC Enterprises

Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE mag...
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