Instruction file names are typically DECRYPT_INSTRUCTION.txt or DECRYPT_INSTRUCTIONS.html.Īs new variants are uncovered, information will be added to the Varonis Connect discussion on Ransomware. Finally, the malware creates a file in each affected directory linking to a web page with decryption instructions that require the user to make a payment (e.g.

CryptoLocker uses an RSA 2048-bit key to encrypt the files, and renames the files by appending an extension, such as. On execution, CryptoLocker begins to scan mapped network drives that the host is connected to for folders and documents ( see affected file-types), and renames and encrypts those that it has permission to modify, as determined by the credentials of the user who executes the code. If you’re interested in reading about ransomware in general, we’ve written A Complete Guide To Ransomware that is very in-depth. They have since been moved to this threat description to minimize confusion between these two ransomware families.“In just one hour, I’ll teach you the fundamentals of Ransomware and what you can do to protect and prepare for it.”įYI, this article is CryptoLocker specific. Noteĭetails of CTB-Locker were originally included in the Cryptolocker description. The desktop background is changed to display the same notice and a copy of the instructions is also saved to the My Documents folder. It will then display a ransom notice and instructions for making the payment, as well as a countdown timer showing how long the user has to pay the ransom demanded. Once run, CTB-Locker will encrypt files on the machine and append the original filenames with a randomly generated 7-character long extension. It will then decrypt and run the ransomware. If the user opens the attachment and runs the executable program, Dalexis will contact a predetermined list of compromised websites and download an encrypted copy of CTB-Locker on the user's machine. This executable is identified as Trojan-Downloader:W32/Dalexis. SCR extension, which makes it appear to be a screensaver program. The attachment contains an executable program that uses the. The attachment may be double-zipped - i.e., a ZIP file contains a second ZIP file. The CTB-Locker is spread in spam email messages containing a file attachment (typically, of type ZIP or CAB). Labs Weblog (9 February 2015): CTB-Locker Infections on the Rise.Once installed on the system, it encrypts files on the system and displays a demand for payment in return for a decryption key to restore access to the affected files. CTB-Locker is downloaded and installed on a system by a separate trojan-downloader program.

Ctb crypto locker