The land down under is not under the radar of cryptomalware.
According to statistics from Symantec, Australia has experienced a surge of attacks since May. During that timeframe there has been an increase of more than 1,300 percent in the occurrence of malware families such as Cryptolocker, Cryptodefense and Cryptowall. Globally, it increased approximately 14-fold during the same period.
“Cryptomalware is a particularly insidious form of threat that encrypts data files on the compromised computer and then attempts to extort money from the victim in order to have the files restored,” according to Symantec’s Security Response team. “Since many of us use personal computers to create and store documents for study or work, as well as media files of precious memories, the loss of these files can be particularly painful. This is what makes this form of extortion so effective for the criminal perpetrators.”
Recent examples of cryptomalware affecting Australian users tend to be from the Trojan.Cryptolocker.F family, explained Symantec.
“This particular threat propagates through email-based social engineering tricks,” the team noted. “These tricks are tailored to the geographic region in which the attacks are being performed, but they all follow a similar modus operandi. In Australia, users are sent emails that typically look like they came from local companies such as an Australian energy supplier (view a bill) or an Australian postal delivery company (details of parcel delivery).”
The attacks typically work this way: the victim receives an email telling them about an offer, bill or parcel delivery. The email asks the user to click a link to get the details or print out a label. Once the link is clicked, the user is presented with a legitimate-looking web page associated with the scam’s theme. The page contains a CAPTCHA code designed for the user to enter so that the attacker knows it is an actual person viewing the webpage.
Once the code is entered, the user is offered a zip file to download and open that is supposed to contain a document but actually holds an .exe file. If the file is downloaded and opened, the malware is executed and begins to search for data files before encrypting them. Once the files are encrypted the victim is presented a message announcing the infection and demanding payment.
“Cryptomalware is an increasingly common menace that is spreading throughout the world,” according to Symantec. “The techniques used, however, are not particularly sophisticated. Users should remain vigilant to the threat that cryptomalware poses and take precautions to avoid suffering the consequences of an infection.”