Lesson 3.5: Common attacks: phishing, malware, password attacks, denial of service
The attack types you'll meet most often and the clues that give them away: phishing and social engineering (urgency, look-alike senders, mismatched reply addresses, failed sender checks), malware (viruses, worms, trojans, ransomware) and how a file's real type and hash expose it, password attacks (brute force, password spraying, credential stuffing) and how their log patterns differ, and denial of service. You triage a suspicious e-mail, its attachment and a night of login failures.
19 min
You will learn to
- Recognise the signs of a phishing e-mail in its headers
- Name the main kinds of malware
- Check a file's real type and compare its hash with a known-bad list
- Tell brute force from password spraying in a log
- Explain denial of service
Key terms
- Social engineering
- Manipulating people into giving away information or doing something unsafe, by using trust, fear, urgency or curiosity.
- Phishing
- Fake messages (e-mail, SMS, chat) that imitate someone trusted to steal passwords or deliver malware. Spear phishing targets one person or team.
- SPF / DKIM / DMARC
- E-mail checks that let a receiving server verify a message really came from the domain it claims. spf=fail is a red flag.
- Malware
- Any software written to harm: virus (attaches to other files), worm (spreads by itself over networks), trojan (pretends to be useful), ransomware (encrypts files for ransom), spyware.
- Brute force
- Trying many passwords against one account until one works.
- Password spraying
- Trying one or a few common passwords against many accounts, slowly, to stay under lockout limits.
- Credential stuffing
- Trying user name and password pairs leaked from another site, betting that people reuse passwords.
- Denial of service (DoS / DDoS)
- Overloading a service so real users can't use it; distributed (DDoS) when the traffic comes from many machines at once.
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