CISSP Blog Post 26, Domain 8: Malware

Credit: Post based on CISSP course presented by Dennis Lee, November 2018

Finally! Congratulations on making it to the last CISSP post in this series. Today we will cover the most exciting topic of Malware! Here are some of the most common types of malware you need to know about:

1. Viruses are malicious code that replicate by creating, replacing, or attacking other programs or files. Viruses generally require some initiating action by the user. Virus Types include File Infectors and Boot Sector Infectors (which are read before the host operating system is started)
2. Worms are a malicious and continuous process that reproduces and eats up resources. Generally it does not require an initiating action by the user. They spread over networks by exploiting vulnerabilities in network protocols, or through application components (e.g. DLLs, etc.) Unlike viruses, worms do not require using infected files to spread (i.e. viruses require a file “host”).
3. Trojans are installed by a user because they think they want it. They are a form of social engineering.
4. Remote Access Tools aka RAT’s can be legitimate remote administration tool but they can also be an illegitimate remote access trojan.
5. Rootkits are often trojans or other malware that can replace critical system files or interfere with system kernel functions to seize control of a processor’s central ring (0 or 1) such that a whole system is compromised.
6. A Logic Bomb is malicious code, often planted by someone you know (i.e. an insider programmer) that is triggered by an event or specific schedule. Usually as an act of revenge.
7. Botnets are where multiple systems are compromised and turned into agents / bots / zombies.
8. Distributed Denial of Service (DDoS) attacks have 3 phases:
   1. Attacker infects many machines with agents (aka bots or zombies)
   2. Attacker uses a Master / Handler program to command agents
   3. Agents initiate denial of service or SPAM attack against attacker’s target ISPs and managed DNS can help stop a DDoS attack.
9. Zero-Day Exploits / Malware are attacks that take place shortly after a security vulnerability is discovered but before a vendor has a fix or patch available.

So how do you protect against Malware? Malware tools come with different types of capabilities including:

• Known Signature Scanning – the program scans based on known malware or attack signatures (e.g. Antivirus). These solutions are only as good as known, available signatures.
• Heuristic Scanning – the program looks for suspicious system behavior or activity. It does NOT use baseline learning, it only uses predefined rules.
• Change Detection Tools look for unauthorized changes to files, system configuration, or programs (e.g. File Integrity Monitoring solutions). These tools take baseline snapshots of files (via a file hash) and then creates new hashes periodically to see if they change.