Complex sentence: CryptoLocker is Trojan horse malware which surfaced in late 2013, a form of ransomware targeting computers running Microsoft Windows, CryptoLocker disguises itself as a legitimate attachment.
Split into simpler sentences: CryptoLocker is Trojan horse malware which surfaced in late 2013. A form of ransomware targeting computers running Microsoft Windows, CryptoLocker disguises itself as a legitimate attachment.