Bitcoin miners

A series of malicious ads sent to Yahoo! users have been designed to turn their computers into components of a Bitcoin mining operation. According to the security firm Light Cyber, the cybercriminals who infected the computers of European Yahoo! users apparently wanted to create a huge Bitcoin network. The malware attack lasted from December 31 to January 3, when Yahoo! detected the problem. The researchers from Light Cyber ??revealed that one of the malware programs was aimed at using the resources of infected PCs to perform the calculations necessary to run a Bitcoin network. The software, initially detected by the security firm Fox IT, spread through a malicious ad campaign on Yahoo!'s advertising server. The malware exploits vulnerabilities in Java to install itself on computers that visited the site ads.yahoo.com. The founder of ??Light Cyber, Giora Engel, told CNET that his company detected the attack on its clients' networks four days before it was made public. Engel explained that “this specific attack campaign incorporates several monetization techniques using a variety of malware. The attackers made sure to exploit each of the millions of infected machines through the use of Bitcoin mining, WebMoney wallet hacking, extraction of personal and banking information, and remote access tools”. Engel also revealed that his company detected that some of the infected computers were communicating with so-called Bitcoin mining pools on the Internet, a sign that they were actually being used for Bitcoin mining. Why did cybercriminals design malware that creates zombie PCs acting as Bitcoin miners? The answer lies in the very origin of virtual currencies. The Bitcoin network creates and distributes a batch of new coins randomly, to someone running the software to generate bitcoins. The probability that one of those users, called miners, receives a batch depends on the power of their computer, so miners join together forming pools or networks. By stealing the computing resources of other machines, the malware author gains a high probability of obtaining batches of bitcoins, while also being the sole beneficiary of the operation.