Sending Apache Logs to LogZilla

Why centralize Apache logs

Apache HTTP Server access and error logs reveal user behavior, performance issues, and attack attempts. Centralizing logs enables correlation across hosts, consistent retention, and faster investigations.

Apache HTTP Server access logging is configured with LogFormat and CustomLog. The Combined Log Format includes Referer and User-Agent.

Data preparation and normalization

• Standardize log formats across hosts. Prefer JSON or a consistent pattern.
• Capture key fields: timestamp, client IP, request method, URI, status, bytes, referer, user‑agent, upstream status/latency if present.
• Tag each event with site, environment, and service identifiers.

For foundational log transport and formatting guidance, see Syslog Essentials which covers reliable delivery methods and structured data practices that complement Apache log centralization.

Field extraction examples (non‑JSON)

• Request path: separate path and query string for aggregation.
• Status class: derive 2xx/3xx/4xx/5xx for quick overviews.
• User identity: if authenticated, carry user/session identifiers.
• Latency: include request and upstream response time when available.

Baselines and detection

• Traffic volume by hour/day and by endpoint group.
• Error rate by status class and top error URLs.
• Authentication anomalies: repeated failures, credential stuffing patterns.
• Suspicious probes: high 404/403 rates on sensitive paths.

Preprocessing upstream (cost and signal)

• Deduplicate exact repeats within a short window for noisy sources.
• Suppress known non‑actionable status lines; retain counts and samples.
• Enrich with site, owner, and service role to accelerate triage.
• Route only security‑relevant streams to premium destinations using intelligent preprocessing patterns.

Dashboards and KPIs

• Top endpoints by latency and error rate.
• Error hotspots by status class and response size.
• Authentication outcomes by user/IP/ASN.
• Request distribution by method and response code.

Example field extraction: JSON input

If Apache emits structured JSON, ensure fields are normalized at ingest.

json
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{
  "ts": "2025-01-01T12:00:00Z",
  "client_ip": "203.0.113.5",
  "method": "GET",
  "uri": "/api/orders?id=123",
  "status": 200,
  "bytes": 5123,
  "referer": "https://example.com/",
  "user_agent": "Mozilla/5.0",
  "upstream_status": 200,
  "upstream_latency_ms": 18
}

Normalize field names (snake_case), types (status as integer), and timestamps in UTC. Derive helpful fields (status_class, endpoint groupings).

Parsing patterns (non‑JSON)

When JSON is not available, use consistent LogFormat and extract:

text
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LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
CustomLog logs/access_log combined

Derivations at ingest:

• status_class: 2xx/3xx/4xx/5xx
• path: path without query string
• endpoint_group: prefix buckets like /api/, /static/, /admin/

Query and dashboard examples

• Errors by endpoint group and status_class over time.
• Top N endpoints by latency and count.
• 4xx/5xx ratio and recent 5xx spikes by service.

Security detection patterns

• High 404 or 403 rate against sensitive paths (/admin, /.git/, /wp-admin).
• Credential stuffing signals: repeated login failures by IP and username.
• Directory traversal attempts (../) and long query strings.
• Sudden surge in unusual user agents or single IP dominance.

For comprehensive web application security monitoring, see OWASP Top 10 detection strategies which covers injection attacks, authentication failures, and other critical vulnerabilities that appear in Apache access logs.

Retention and routing strategy

• Keep hot data for high‑value endpoints and error views.
• Route low‑value, repetitive noise as summaries to lower‑cost stores.
• Retain raw duplicates upstream; index first occurrences and summaries.

For comprehensive cost optimization strategies, see Cloud SIEM cost‑control approaches which details tiered storage, selective routing, and volume management techniques applicable to Apache log workflows.

Implementation blueprint

1. Standardize LogFormat (or JSON) across all Apache hosts.
2. Extract fields and enforce a minimal schema in the ingest pipeline.
3. Add enrichment for site, env, owner, and service.
4. Enable dedup window for identical lines; forward first occurrence.
5. Build starter dashboards for latency and error hotspots.
6. Tune suppression for non‑actionable noise; keep accurate counts.

Micro-FAQ

Which fields should be captured from Apache access logs?

Timestamp, client IP, method, URI, status, bytes, referer, and user agent, plus upstream status/latency when available.

Is JSON required for analysis?

No. Non‑JSON formats work if fields are consistently extracted. JSON simplifies parsing and schema validation in pipelines.

How does preprocessing help?

Upstream dedup and suppression reduce redundant lines before indexing, while enrichment adds context for faster triage and better routing.

Next Steps

• Roll out normalization and enrichment on a subset of hosts and validate search improvements.
• Expand to all hosts, add security‑focused views, and measure incident response time deltas.