Attack Surface and Attack Vectors

Attack surface is the total sum of all the vulnerabilities in a given computing device or network that are accessible to the attackers. Attack surface may be categorized into different areas, such as software attack surfaces (open ports on a server), physical attack surfaces (USB ports on a laptop), network attack surfaces (console ports on a router), and human/social engineering attack surfaces (employees with access to sensitive information).

Attack vectors are the paths or means by which the attackers gain access to a resource (such as end-user hosts or servers) in order to deliver malicious software or malicious outcome. Attack vectors enable the attackers to exploit system vulnerabilities. Many attack vectors take advantage of the human element in the system, because that is often the weakest link. For example, if the attack vector is a malicious file, then the victim needs to be tricked into opening it for the attack to work.

A smaller attack surface can help make the organization less exploitable, reducing the risk. A greater attack surface makes the organization more vulnerable to attacks, which increases the risk

Attack surfaces can be divided in to the following four categories:

  • The network attack surface comprises all vulnerabilities that are related to ports, protocols, channels, devices (smart phones, laptops, routers, and firewalls), services, network applications (SaaS), and even firmware interfaces. For example, some network protocols are inherently more insecure than others as they pass data over the network unencrypted. These protocols include Telnet, FTP, HTTP, and SMTP. Many network file systems, such as NFS and SMB, pass information over the network unencrypted. Remote memory dump services, like netdump, also pass the contents of memory over the network unencrypted. Memory dumps can contain passwords or, even worse, database entries and other sensitive information. Other services, such as finger and rwhod , reveal information about users of the system. Network printers are also the target of a wide array of attacks from hackers because the operating system driver, management tools, and the printer’s software make them vulnerable. Printers can be attacked via the web-based administrative interface, SMTP, FTP, and SNMP.
  • The software attack surface is the complete profile of all functions in any code that is running in a given system that is available to an unauthenticated user. An attacker or a piece of malware can use various exploits to gain access and run code on the target machine. The software attack surface is calculated across many different kinds of code, including applications, email services, configurations, compliance policy, databases,
    executables, DLLs, web pages, mobile apps, device OS, and so on. Unpatched software, such as Java, Adobe Reader, and Adobe Flash, also provide greater software attack surface because they are widely used. Publicly known cybersecurity vulnerabilities are listed in CVE libraries. Common CVE identifiers make it easier to share data across separate network security databases and tools, and provide a baseline for evaluating the coverage of an organization’s security tools.
  • The physical attack surface is composed of the security vulnerabilities in a given system that are available to an attacker in the same location as the target. The physical attack surface is exploitable through inside threats such as rogue employees, social engineering ploys, and intruders who are posing as service workers. External
    threats include password retrieval from carelessly discarded hardware, passwords on sticky notes, and physical break-ins. Also, consider a scenario where an intruder steals or downloads the information from an entire drive and extracts the target data in the future.
  • The social engineering attack surface usually takes advantage of human psychology: the desire for something free, the susceptibility to distraction, or the desire to be liked or to be helpful. A few examples of human social engineering attacks are fake calls to IT, where the attacker is posing as an employee to get a password; or media drops where an employee might find a flash drive in the parking lot, and when they use that device, they inadvertently execute automatic running code leading to a data breach. Socially engineered Trojans provide another method of attack. An end user browses to a website that is usually trusted, which prompts the end user to run a Trojan. Most of the time the website is a legitimate, innocent victim that has been temporarily compromised by hackers. Another very popular method is an APT attacker sends a very specific phishing campaign, which is known as spear-phishing, to multiple employees’ email addresses. The phishing email contains a Trojan attachment, which at least one employee is tricked into running. After the initial execution and first computer takeover, an APT attacker can compromise an entire enterprise in a short time.

An attack vector is a path or route by which an attack was carried out. Examples of attack vectors include malware that is delivered to users who are legitimately browsing mainstream websites, spam emails that appear to be sent by well-known companies but contain links to malicious sites, third-party mobile applications that are laced with malware that are downloaded from popular online marketplaces, and insiders using information access privileges to steal intellectual property from employers.

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