How forensics works
Investigators begin by securing evidence without altering it, often by taking disk images and memory captures and recording a chain of custody. Hash values prove that copies match the originals, which helps preserve the evidence's credibility.
Analysis then reconstructs a timeline from sources such as system logs, file system artifacts, network captures and memory. Investigators identify the entry point, attacker actions, affected accounts and data, and any persistence the attacker left behind. Common evidence sources include disk images, memory captures, event logs, browser history, email, cloud audit trails and network flow records, each telling part of the story.
Why it matters for Canadian organizations
After an incident, organizations need facts: how the attacker got in, what they accessed and whether they are gone. Breach notification decisions under PIPEDA and Quebec Law 25 depend on understanding whether personal information was actually affected.
Forensic findings also feed cyber insurance claims and can matter in litigation. Evidence handled carelessly, such as rebooting or wiping a system too early, may be lost, so planning ahead improves the quality of any later investigation. Reports should be factual and reproducible, since they may be reviewed by insurers, regulators, opposing counsel or the organization's own board after the event.
How to implement it
Prepare before an incident. Enable and retain meaningful logs, keep accurate time synchronization, and define who may collect evidence and how. Know when to call specialists rather than improvising.
During an incident, preserve volatile data first, avoid unnecessary changes to affected systems, document every action, and work from copies. Tie the findings back into hardening and detection improvements afterward. Engage counsel early when litigation or regulatory scrutiny is likely, because the way an investigation is commissioned can affect how its findings are treated later.
Frequently asked questions
What is the difference between forensics and incident response?
Incident response focuses on containing and recovering from an incident. Forensics focuses on establishing what happened using preserved evidence. The two overlap and are usually performed together, with forensic findings guiding response decisions and later improvements.
How long does a forensic investigation take?
It depends on the number of systems, the quality of available logs and the questions being asked. A narrow investigation may take days, while a complex intrusion can take weeks. Good logging and early evidence preservation shorten the process considerably.
Can deleted files be recovered in a forensic investigation?
Often partly. Deleted data may remain on disk until overwritten, and artifacts such as logs, caches and memory can reveal activity. Recovery is never guaranteed, especially on solid-state drives or after secure wiping, which is why quick preservation matters.
Related service: Cyber defense