The Internet Crime Complaint Center noticeboard carries phishing and ransomware alerts. This includes protection against malware, ransomware, exploit, and malicious websites. This section only applies to malware designed to operate undetected, not sabotage and ransomware. Another major ransomware Trojan targeting Windows, CryptoWall, first appeared in 2014. Some new viruses, particularly ransomware, use polymorphic code to avoid detection by virus scanners. In 2012, a major ransomware Trojan known as Reveton began to spread. In February 2013, a ransomware Trojan based on the Stamp. Carbonite offers telephone support to recover from ransomware viruses. Starting from around 2012 the use of ransomware scams has grown internationally. Bitcoin was used as the ransom medium in the WannaCry ransomware. Cyber attacks, including ransomware, can be used to generate income. With the locker ransomware just locking down a computer system without encrypting its contents. The cyberattack was based on a modified version of the Petya ransomware. This feature is designed mainly to defend against file-encrypting ransomware. Many types of ransomware demand payment in bitcoin.