Figure \[fig:url\].

![image](url_example.jpg){width="120mm"}

Compromised URLs that are used for cyber attacks are termed as *malicious URLs*. In fact, it was noted that close to one-third of all websites are potentially malicious in nature [@liang2009malicious], demonstrating rampant use of malicious URLs to perpetrate cyber-crimes. A Malicious URL or a malicious web site hosts a variety of unsolicited content in the form of spam, phishing, or drive-by-exploits in order to launch attacks. Unsuspecting users visit such web sites and become victims of various types of scams, including monetary loss, theft of private information (identity, credit-cards, etc.), and malware installation. Popular types of attacks using malicious URLs include: Drive-by Download, Phishing and Social Engineering, and Spam [@patil2015survey]. Drive-by-download [@cova2010detection] refers to the (unintentional) download of malware upon just visiting a URL. Such attacks are usually carried out by exploiting vulnerabilities in plugins or inserting malicious code through JavaScript. Phishing and Social Engineering attacks [@heartfield2015taxonomy] trick the users into revealing private or sensitive information by pretending to be genuine web pages. Spam is the usage of unsolicited messages for the purpose of advertising or phishing. These types of attacks occur in large numbers and have caused billions of dollars worth of damage every year. 