Governance & Risk Management , Next-Generation Technologies & Secure Development
FBI Alert: $18 Million in Ransomware LossesOngoing CryptoWall Attacks Lead to Major Expenses
In the past year, U.S. businesses and consumers have experienced more than $18 million in losses stemming from a single strain of ransomware called CryptoWall, according to the Internet Crime Complaint Center.
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In total, IC3 - a collaboration between the FBI and the National White Collar Crime Center - says it received 992 CryptoWall-related complaints from April 2014 to June 2015. And it says the reported losses relate not just to ransom payments potentially made by victims, but additional costs that can include "network mitigation, network countermeasures, loss of productivity, legal fees, IT services and/or the purchase of credit monitoring services for employees or customers."
Ransomware is a type of malware that locks victims' PCs and may encrypt all of the user data on them, making it impossible to retrieve the data until victims pay attackers a ransom. Of course, even if victims pay, there is no guarantee that they will regain access to their PC or obtain the decryption key for their data (see Ransomware: 7 Defensive Strategies).
The quantity of ransomware attacks continues to escalate, security experts say, because it offers criminals the potential for high rewards with little risk (see Crime: Why So Much Is Cyber-Enabled). Indeed, ransomware attacks can be launched en masse by remote attackers and are relatively cheap and easy to perpetrate. Even the process of collecting payments from victims - often payable in bitcoins - and providing decryption keys can be automated.
"In most cases, once the victim pays a ransom fee, he or she regains access to the files that were encrypted," IC3 reports. "Most criminals involved in ransomware schemes demand payment in Bitcoin. Criminals prefer Bitcoin because it's easy to use, fast, publicly available, decentralized and provides a sense of heightened security/anonymity."
Because ransomware can rely so heavily on social engineering - tricking - victims into executing related malware or falling for ransom scams, many security experts have urged businesses to continually educate their employees and customers about ways to spot such attacks and defend themselves (see Ransomware Attacks' New Focus: Businesses).
Click-Fraud Attack Spike
Earlier this month, security firm Symantec warned that it had seen a spike in attacks that began with the year-old Poweliks Trojan, which was designed to perpetrate click fraud, and which also downloaded CryptoWall onto an infected system (see Ransomware Gets a New Twist?). Click fraud refers to infecting systems with malware that is used to make "bogus requests" for online advertising, without the malware revealing its presence to the user of the infected system.
Using a single piece of malware - or "dropper" - to infect a system and then download and install many other types of malware onto the same system is not a new attack technique.
For example, authorities have accused the gang behind Gameover Zeus of first using that Trojan to harvest bank credentials, and then infecting systems with Cryptolocker ransomware (see Gameover Zeus Trojan Returns). The U.S. Department of Justice believes that the Gameover Zeus gang is responsible for more than $100 million in losses via the banking Trojan, and netted $27 million in ransom payments in just the first two months they began using Cryptolocker.
Attacks Get Modular
But attackers have been retooling their malware to make it easier to rapidly infect PCs with multiple types of malware. Security firm Trend Micro warned in 2013 that the aging Asprox botnet, which was first discovered in 2007, had re-emerged "with a new and improved modular framework," and been rebranded as Kuluoz malware, which was a dropper designed to download additional malware onto infected PCs.
By December 2014, the Level 42 threat-intelligence research group at security vendor Palo Alto Networks reported seeing a spike in Asprox-related attack activity. "This malware sends copies of itself over email quickly and to users all around the world and then attempts to download additional malware," it said. The researchers noted that of the 4,000 organizations that it was monitoring, the malware had been tied to "approximately 80 percent of all attack sessions" seen in October and had attempted to infect nearly half of all those organizations.
Also in December, the Association of National Advertisers warned that U.S. businesses were losing about $6.3 billion annually to click fraud. The same month, a study conducted for the ANA by the security firm White Ops found that botnets were responsible for "viewing" 11 percent of all online advertisement, and 23 percent of all online video advertisements.
Asprox Botnet Serves CryptoWall
But click-fraud malware attacks are increasingly blended with other types of malware as attackers attempt to monetize infected PCs as much - and as rapidly - as possible.
In a recent series of attacks, Asprox malware - now typically distributed via phishing attacks - "phoned home" to the Asprox command-and-control server after it infected a PC, and received back the Zemot dropper malware, according to a new report released by the security firm Damballa. The dropper then downloaded the Rovnix rootkit, as well as Rerdom, which is a click-fraud installer.
Damballa says that it has also seen Zemot get installed via crimeware toolkit exploits, which can exploit systems using known vulnerabilities, for example if attackers compromise otherwise legitimate websites and use them to launch drive-by attacks.
Inside enterprises, "click fraud is generally viewed as a low-priority risk," Damballa says. "In reality, click fraud is often a precursor to something more sinister. A device infected with click-fraud [malware] may leave the enterprise susceptible to dangerous downstream infections."
Indeed, Damballa reports that tests of Asprox-infected machines found that over the course of two hours, a single PC was infected with three different types of click-fraud malware, as well as the CryptoWall ransomware. Even after CryptoWall encrypted much of the infected PC's hard drive, furthermore, the click-fraud malware continued to operate, so long as the machine remained Internet-connected.