Part 1 — Lab Answers
Reference solutions for the lab exercises. Use these only after attempting the exercises yourself.
Exercise 1 — Web Access Log Triage
Primary attacker: a single source IP hammering the login endpoint with 4xx responses, then suddenly returning 200s after hitting an admin path — classic credential-stuffing → admin panel access. Look for sqlmap, nikto, or gobuster user-agents, and any ../ / %2e%2e sequences. MITRE: T1110.003 (password spray), T1083 (file discovery), T1190 (exploit public-facing app).
Sigma rule sketch:
title: Web Login Brute Force Followed by Success
logsource: {product: apache, service: access}
detection:
spray:
cs-method: POST
cs-uri-stem: '/login'
sc-status: 401
success:
cs-method: POST
cs-uri-stem: '/login'
sc-status: 200
condition: spray | count(c-ip) > 20 near success
fields: [c-ip, cs-uri-stem, sc-status]
level: high
tags: [attack.credential_access, attack.t1110]
Exercise 2 — Linux Syslog Analysis
Narrative: repeated SSH failures from one external IP, eventual success, then immediate sudo su -, then a new cron job in /etc/cron.d/ calling curl | sh. That is T1110.001 → T1078 → T1548 → T1053.003. The killer evidence is the cron entry: persistence is a one-line giveaway.
Top 3: (1) successful SSH after brute force, (2) sudo to root, (3) new cron job pulling remote code.
Exercise 3 — Windows Security Events
Look for Event 4624 type 3 (network logon) from a workstation IP to the DC with a service account — that is often lateral movement. Pair with 4672 (special privileges) to confirm privilege escalation. 4769 with RC4_HMAC = Kerberoasting. A single user showing 4624s across many hosts in minutes = lateral movement. Map to T1021.002, T1558.003, T1078.
Exercise 4 — Cloud Audit Log Review
Root cause: typically a CreateAccessKey on an existing IAM user, followed by AttachUserPolicy granting AdministratorAccess, followed by PutBucketAcl making an S3 bucket public. The first suspicious call is the key creation from an unusual source IP. MITRE cloud: T1098.001, T1562.008, T1537.
Containment: delete the key immediately, detach the policy, revoke any active sessions.
Final Exercise — Cross-Log Correlation
The web log attacker IP often appears in CloudTrail (source IP of the API call) and in syslog (same IP doing SSH). One shared indicator across 3 sources collapses 4 separate alerts into 1 incident. Earliest sign: the web login spray, because it pre-dates credential capture by minutes to hours.
Part 2 — Homework Answers
Model answers for the homework tasks. Your solution may differ and still be correct.
Task 1 — Detection Pack
Expect a 5-rule pack with clean metadata, tuned FPs, and MITRE tags. Grade on: uniqueness per source, realistic FP notes, and that each rule has a specific string/field match (not just severity filtering).
Task 2 — Detection Benchmark
Typical result: AI is 3-5x faster on the first pass but misses 1-2 subtle findings that a human analyst catches by cross-referencing memory. Human wins on context; AI wins on volume.
Task 3 — Personal SIEM Notebook
A good prompt library has one prompt per source, each parameterized with "paste log here" and each specifying desired output format. Bonus if the learner includes a "confidence" column in outputs.