🦠 Malware Types & Analysis

Comprehensive guide to malicious software classification and detection

CRITICAL
🦠
Virus
Self-replicating malware
📋 Characteristics
  • Requires host file to spread
  • Modifies or attaches to legitimate files
  • Activates when infected file is executed
  • Can corrupt or delete data
🎯 Common Targets
  • Executable files (.exe, .com)
  • Boot sectors
  • Macro-enabled documents
  • Script files
🔍 Detection Signs
  • Unexpected file size changes
  • System performance degradation
  • Unusual disk activity
  • Modified file timestamps
CRITICAL
🐛
Worm
Self-propagating malware
📋 Characteristics
  • Spreads without user interaction
  • Exploits network vulnerabilities
  • Creates copies of itself
  • Can cause network congestion
🌐 Propagation Methods
  • Email attachments
  • Network shares
  • Vulnerable services
  • USB devices
🔍 Detection Signs
  • Unusual network traffic
  • Slow network performance
  • Duplicate files across systems
  • Mass email sending
HIGH
🐴
Trojan Horse
Disguised malware
📋 Characteristics
  • Disguised as legitimate software
  • Requires user execution
  • Creates backdoors
  • Does not self-replicate
🎭 Common Types
  • Banking Trojans
  • Remote Access Trojans (RAT)
  • Downloader Trojans
  • Info-stealer Trojans
🔍 Detection Signs
  • Unexpected network connections
  • New user accounts
  • Modified security settings
  • Unusual process activity
CRITICAL
🔒
Ransomware
Encryption extortion
📋 Characteristics
  • Encrypts user files
  • Demands ransom payment
  • Often has time limits
  • May threaten data leak
🔐 Attack Vectors
  • Phishing emails
  • RDP exploitation
  • Software vulnerabilities
  • Supply chain attacks
🔍 Detection Signs
  • Mass file renaming
  • Encrypted file extensions
  • Ransom notes in folders
  • Shadow copy deletion
HIGH
👁️
Spyware
Information theft
📋 Characteristics
  • Monitors user activity
  • Steals sensitive data
  • Runs hidden in background
  • Sends data to C2 server
📊 Data Collected
  • Keystrokes (keyloggers)
  • Screenshots
  • Browser history
  • Login credentials
🔍 Detection Signs
  • Slow system performance
  • Unusual network activity
  • Browser redirects
  • New browser toolbars
MEDIUM
📢
Adware
Advertising malware
📋 Characteristics
  • Displays unwanted ads
  • Redirects web searches
  • Collects browsing data
  • Slows down system
🎯 Common Behaviors
  • Pop-up advertisements
  • Browser homepage changes
  • New toolbars installation
  • Search engine hijacking
🔍 Detection Signs
  • Excessive pop-ups
  • Browser performance issues
  • Unexpected toolbars
  • Changed browser settings
CRITICAL
🌳
Rootkit
Stealth malware
📋 Characteristics
  • Hides deep in system
  • Modifies OS functions
  • Conceals other malware
  • Difficult to detect/remove
🎯 Types
  • Kernel-level rootkits
  • User-mode rootkits
  • Bootkit (boot sector)
  • Firmware rootkits
🔍 Detection Signs
  • Unusual system behavior
  • Slow performance
  • Modified system files
  • AV software malfunction
HIGH
🤖
Botnet
Zombie network
📋 Characteristics
  • Remote controlled
  • Part of larger network
  • Used for attacks
  • Often undetected
🎯 Common Uses
  • DDoS attacks
  • Cryptocurrency mining
  • Spam distribution
  • Click fraud
🔍 Detection Signs
  • Unusual network traffic
  • IRC/P2P connections
  • High CPU usage
  • Slow internet speed

🔄 Typical Malware Infection Stages

1
Entry
Initial system breach via email, web, USB, or exploit
2
Installation
Malware drops payload and establishes foothold
3
Persistence
Creates mechanisms to survive reboots
4
Communication
Establishes C2 channel for commands
5
Execution
Performs malicious activities

🔍 Detection & Analysis Methods

📝
Static Analysis
Examining malware without execution - file hashes, strings, PE headers
⚡
Dynamic Analysis
Running malware in sandbox to observe behavior
🧬
Signature-Based
Matching known malware patterns and hashes
🎯
Heuristic Analysis
Detecting suspicious behaviors and patterns
🤖
Machine Learning
AI-based detection of unknown threats
🌐
Network Analysis
Monitoring network traffic for C2 communications

⚡ Notable Malware in History

1988
Morris Worm
First major internet worm, infected 10% of connected computers
2000
ILOVEYOU
Email worm that caused $10 billion in damages worldwide
2010
Stuxnet
First known malware to target industrial control systems
2013
CryptoLocker
Pioneer ransomware that popularized crypto-ransomware
2017
WannaCry
Ransomware worm that affected 230,000 computers in 150 countries
2020
Emotet
Banking trojan evolved into malware-as-a-service platform

🛡️ Defense-in-Depth Prevention Strategy

🌐

Network Layer

Firewalls, IDS/IPS, network segmentation, DNS filtering, proxy servers

💻

Endpoint Protection

Antivirus, EDR/XDR, application whitelisting, patch management, host firewall

📧

Email Security

Spam filters, attachment scanning, sandboxing, phishing protection, DMARC/SPF

👤

User Training

Security awareness, phishing simulations, safe browsing habits, incident reporting

💾

Backup & Recovery

Regular backups, offline storage, tested recovery procedures, immutable backups