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The 5 Logs Most Often Missing During Breach Investigations
And Why Security Teams Realise Too Late
When breach investigations stall, it’s rarely because analysts lack tools.
It’s because the evidence they need doesn’t exist anymore — filtered out, overwritten, never collected, or priced out of reach.
Across incident response reviews in 2024 and 2025, one pattern kept repeating:
the same critical logs were missing again and again.
This blog breaks down the five logs most often absent during breach investigations, why they disappear, and how modern logging strategies prevent those gaps — without exploding SIEM costs.
Why “We Have Logs” Isn’t the Same as “We Have Evidence”
Most organisations do log something.
The problem is what survives long enough to be useful.
Common causes of missing logs:
- SIEM ingestion caps
- Short retention windows
- Over-aggressive filtering
- Inconsistent endpoint policies
- Logging treated as an infrastructure concern, not an investigation requirement
By the time an incident is detected, the most valuable evidence has often already rolled off
1. Authentication & Privilege Escalation Logs
What’s missing
- Failed and successful login attempts
- Lateral authentication activity
- Privilege elevation events
Why they disappear
- High volume → aggressively filtered
- Considered “too noisy”
- Retention sacrificed to save SIEM costs
Why they matter
Authentication logs are the starting point of almost every breach investigation.
Without them, teams cannot answer:
- How the attacker got in
- Whether credentials were abused
- How access expanded over time
Prevention strategy
- Collect at the endpoint
- Filter intelligently (not blindly)
- Route high-risk authentication events to SIEM
- Retain full-fidelity audit trails elsewhere
2.Process Execution & Command-Line Activity
What’s missing
- Process creation events
- Parent/child relationships
- Command-line arguments
Why they disappear
- High event frequency
- Often excluded to reduce volume
- Seen as “endpoint noise”
Why they matter
This is where attackers:
- Run malware
- Execute living-off-the-land techniques
- Disable security controls
Without process execution logs, investigations lose cause-and-effect visibility.
Prevention strategy
- Preserve execution context at the source
- Keep command-line arguments intact
- Avoid SIEM-only retention models
Platforms like Snare help by filtering low-risk noise before ingestion while preserving high-value execution evidence for investigations.
3.Account Creation, Modification & Deletion Logs
What’s missing
- Temporary admin account creation
- Privilege changes
- Account cleanup after compromise
Why they disappear
- Low perceived frequency
- Often spread across systems
- Logging policies differ by platform
Why they matter
Attackers frequently:
- Create backdoor accounts
- Modify existing privileges
- Remove accounts to erase traces
Missing these logs means missing persistence mechanisms.
Prevention strategy
- Standardise account lifecycle logging
- Treat identity logs as non-negotiable
- Enforce consistent retention
4.Configuration & Security Policy Change Logs
What’s missing
- Logging service changes
- Firewall or security policy edits
- Endpoint agent tampering
Why they disappear
- Logged locally but not forwarded
- Retention too short
- Considered “administrative noise”
Why they matter
Attackers often disable or weaken controls before acting.
If configuration changes aren’t logged and preserved:
- You can’t prove when controls failed
- You can’t show whether failure was malicious or accidental
Prevention strategy
- Treat configuration logs as evidence
- Preserve timestamps and integrity
- Monitor for logging interruptions
5.Log Tampering & Logging Service Interruptions
What’s missing
- Log deletion attempts
- Agent stoppage events
- Gaps in log timelines
Why they disappear
- Logging systems don’t log their own failure
- Alerts focus on data, not absence
- No monitoring for “expected logs missing”
Why they matter
Missing logs are often the clearest sign of attacker activity.
If you can’t prove logs were tampered with —
You can’t trust what remains.
Prevention strategy
- Monitor for expected log gaps
- Alert on logging service changes
- Preserve chain-of-custody
The Common Root Cause: Logs Are Filtered Too Late
Across investigations, the issue isn’t too little logging.
It’s that:
- Filtering happens after ingestion
- Cost controls override investigation needs
- Logging strategies aren’t designed backward from evidence
When logs are filtered at the endpoint, with policy and intent, teams avoid this trade-off.
This is where Snare fits — enabling:
- High-fidelity endpoint log collection
- Policy-based filtering before SIEM costs apply
- Routing logs by purpose (SIEM, archive, analytics)
- Preservation of forensic integrity
A Simple Test: Are You Missing These Logs Right Now?
Ask your team:
- Can we reconstruct authentication activity 90 days ago?
- Do we retain command-line arguments?
- Can we prove no one disabled logging?
- Do we detect when expected logs stop arriving?
If the answer to any is “not sure” — you already have blind spots.
