Network Attacks

Identify security vulnerabilities.

Types of Malware

• Malware is short for malicious software. It is code or software specifically designed to damage, disrupt, steal, or inflict “bad” or illegitimate action on data, hosts, or networks.
• The following are types of malware:
• • Viruses – A computer virus is a type of malware that propagates by inserting a copy of itself into, and becoming part of, another program. It spreads from one computer to another, leaving infections as it travels.
  • Worms – Computer worms are similar to viruses in that they replicate functional copies of themselves and can cause the same type of damage. In contrast to viruses, which require the spreading of an infected host file, worms are standalone software and do not require a host program or human help to propagate.
  • Trojan Horses – It is a harmful piece of software that looks legitimate. Unlike viruses and worms, Trojan horses do not reproduce by infecting other files. They self-replicate. Trojan horses must spread through user interaction such as opening an email attachment or downloading and running a file from the internet.

Reconnaissance Attacks

• In addition to malicious code attacks, it is also possible for networks to fall prey to various network attacks.
• Network attacks can be classified into three major categories:
• • Reconnaissance attacks – The discovery and mapping of systems, services, or vulnerabilities.
  • Access attacks – The unauthorized manipulation of data, system access, or user privileges.
  • Denial of service – The disabling or corruption of networks, systems, or services.
• For reconnaissance attacks, external threat actors can use internet tools, such as the nslookup and whois utilities, to easily determine the IP address space assigned to a given corporation or entity.
• After the IP address space is determined, a threat actor can then ping the publicly available IP addresses to identify the addresses that are active.

Access Attacks

• Access attacks exploit known vulnerabilities in authentication services, FTP services, and web services to gain entry to web accounts, confidential databases, and other sensitive information.
• Access attacks can be classified into four types:
• • Password attacks – Implemented using brute force, trojan horse, and packet sniffers
  • Trust exploitation – A threat actor uses unauthorized privileges to gain access to a system, possibly compromising the target.
  • Port redirection: – A threat actor uses a compromised system as a base for attacks against other targets. For example, a threat actor using SSH (port 22) to connect to a compromised host A. Host A is trusted by host B and, therefore, the threat actor can use Telnet (port 23) to access it.
  • Man-in-the middle – The threat actor is positioned in between two legitimate entities in order to read or modify the data that passes between the two parties.

Denial of Service Attacks

• Denial of service (DoS) attacks are the most publicized form of attack and among the most difficult to eliminate.
• However, because of their ease of implementation and potentially significant damage, DoS attacks deserve special attention from security administrators.
• • DoS attacks take many forms. Ultimately, they prevent authorized people from using a service by consuming system resources. To help prevent DoS attacks it is important to stay up to date with the latest security updates for operating systems and applications.
  • DoS attacks are a major risk because they interrupt communication and cause significant loss of time and money. These attacks are relatively simple to conduct, even by an unskilled threat actor.
  • A DDoS is similar to a DoS attack, but it originates from multiple, coordinated sources. For example, a threat actor builds a network of infected hosts, known as zombies. A network of zombies is called a botnet. The threat actor uses a command and control (CnC) program to instruct the botnet of zombies to carry out a DDoS attack.

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