Digital Forensics for Law Firms: What It Actually Involves (And Why It Matters)

The Question That Changes Everything

"We need to know what they took."

In fifteen years of digital forensics work, I've heard this question hundreds of times. It usually comes 24-48 hours after a firm discovers something is wrong — an unusual login, a ransom note, a client asking why their confidential documents are circulating online.

By that point, the technical incident may be contained. But the harder question remains: what was accessed, exfiltrated, or compromised?

For law firms, this question carries weight that other industries don't face. Legal professional privilege. Client confidentiality obligations. Duties to the court. Regulatory notification requirements under the Privacy Act.

The answer shapes everything that follows.

What Digital Forensics Actually Is

Digital forensics is the process of collecting, preserving, analysing, and presenting electronic evidence in a way that maintains its integrity and admissibility.

That last part matters more than most people realise.

When your IT team "has a look" at a compromised system, they're trying to fix the problem. Understandable. But in doing so, they may be overwriting timestamps, clearing logs, or modifying the very evidence you'll need later.

Digital forensics takes a different approach. We create forensic images — bit-for-bit copies of storage media that capture everything, including deleted files, system artifacts, and metadata. The original evidence remains untouched.

This isn't academic. I've seen insurance claims denied because the firm couldn't demonstrate what was or wasn't accessed. I've seen regulatory investigations complicated because the evidence chain was broken. I've seen litigation positions compromised because metadata was inadvertently altered.

Why Law Firms Are Different

Every organisation faces cyber risk. But law firms carry unique considerations that change how forensic investigations must be conducted.

Legal Professional Privilege

Forensic investigators will inevitably encounter privileged material during an investigation. How that material is handled matters enormously.

A forensic provider without legal sector experience may not recognise the implications of what they're seeing. They may include privileged content in reports that are later discoverable. They may share information with insurers or regulators without appropriate protections.

The solution isn't to avoid forensics — it's to work with providers who understand privilege and can structure investigations appropriately, often under the direction of external legal counsel to maintain privilege over the investigation itself.

Client Notification Decisions

When client data is potentially compromised, firms face difficult decisions about notification. Too early, and you're alarming clients based on incomplete information. Too late, and you've breached trust and potentially regulatory obligations.

Digital forensics provides the evidence base for these decisions. We can often determine with reasonable confidence which matters were accessed, which documents were viewed, and which data was exfiltrated. This allows targeted, proportionate notification rather than blanket communications.

Matter-Specific Implications

A breach affecting a family law practice has different implications than one affecting a commercial litigation firm. A matter involving a listed company has disclosure considerations. A matter involving government has notification requirements.

Forensic analysis needs to be prioritised accordingly — focusing first on the matters where compromise would have the most significant consequences.

What We Actually Examine

Digital forensics in a law firm context typically involves several workstreams running in parallel.

Endpoint Analysis

Workstations and laptops often hold the most relevant evidence. We examine:

- Login events and authentication logs
- File access patterns and timestamps
- Email client artifacts (sent items, drafts, deleted messages)
- Browser history and cached credentials
- USB device connections and file transfers
- Remote access tool artifacts
- Malware persistence mechanisms

Server and Infrastructure Analysis

Document management systems, email servers, and file shares contain crucial evidence about what was accessed at scale. We look at:

- DMS audit logs (who accessed which matters and when)
- Email server logs (which mailboxes were accessed)
- Active Directory authentication events
- Network traffic logs and firewall data
- Backup system logs (were backups accessed or deleted?)

Cloud Service Analysis

Most firms now have significant cloud footprints. Microsoft 365, cloud-based practice management systems, and file sharing services all generate logs that can reveal attacker activity:

- Azure AD sign-in logs (including geographic location)
- SharePoint and OneDrive access logs
- Email forwarding rules (a common persistence mechanism)
- OAuth application consents
- Conditional access policy events

Timeline Reconstruction

The goal of all this analysis is to construct a coherent timeline: when did the attacker gain access, what did they do, how long were they present, and what did they take?

This timeline becomes the foundation for every decision that follows — regulatory notification, client communication, insurance claims, and potential litigation.

The First 24 Hours Matter

Here's the uncomfortable truth: evidence degrades rapidly after an incident.

Logs rotate and overwrite. Memory contains volatile data that disappears when systems reboot. Attackers may still be present, actively covering their tracks.

The decisions made in the first 24 hours — often by people under enormous pressure with incomplete information — determine whether a thorough forensic investigation is even possible.

What to do:

- Don't turn off affected systems (this destroys memory evidence)
- Don't "clean up" or reinstall systems before imaging
- Don't let well-meaning IT staff "have a look" without forensic guidance
- Do preserve logs immediately (email server, DMS, firewalls, cloud services)
- Do document everything (screenshots, photos, written notes with timestamps)
- Do engage forensic support early — even if just for advice

What not to do:

- Don't assume IT remediation and forensic investigation are the same thing
- Don't delay forensics until "things calm down"
- Don't assume cloud services retain logs indefinitely (many have 30-90 day windows)
- Don't communicate about the incident over potentially compromised channels

The "IT Guy Had a Look" Problem

I understand why this happens. A firm discovers something suspicious. The natural instinct is to ask the IT team either internal or outsource, to investigate.

The IT team's job is to fix problems and restore service. They're good at this. But their approach is fundamentally different from forensic investigation.

When IT "has a look," they're typically:

- Logging into affected systems (modifying access timestamps)
- Running antivirus scans (potentially quarantining evidence)
- Checking and clearing logs (to understand what happened)
- Resetting passwords and patching systems (necessary, but destroys artifacts)
- Restoring from backups (overwriting the compromised state)

None of this is wrong from an IT perspective. But it can significantly complicate or even prevent effective forensic analysis.

The solution is coordination. Forensic imaging should happen before remediation where possible. If immediate remediation is necessary (to stop ongoing data exfiltration, for example), at minimum preserve logs and document the system state before making changes.

When Forensics Becomes Litigation Support

Sometimes a cyber incident leads to litigation — against the attacker (rarely successful), against vendors or service providers (more common), or defence against claims from affected parties (increasingly common).

When this happens, forensic evidence becomes legal evidence. The standards change.

Chain of custody documentation becomes critical. The forensic methodology must withstand cross-examination. Reports must be written with the assumption they'll be read by opposing counsel.

This is why engaging forensic providers with litigation experience matters. We understand what "forensically sound" actually means in a courtroom context. We know how to document our methodology. We know how to write reports that support legal arguments without overreaching.

Choosing a Forensic Provider

Not all forensic providers are created equal. When evaluating options, consider:

Legal Sector Experience

Do they understand privilege? Have they worked with law firms before? Do they know what a DMS is?

Certification and Methodology

Look for recognised certifications (GIAC Forensic Analyst, Vendor Certifications etc.) and documented methodologies. This matters if evidence ever goes to court.

Availability

Incidents don't happen during business hours. What's their response time commitment? Do they have capacity to respond to your incident, or will you be waiting behind other clients?

Jurisdiction

For Australian firms, there are advantages to Australian-based providers who understand local regulatory requirements, can appear in Australian courts, and aren't subject to foreign discovery obligations.

Insurance Panel Status

If you have cyber insurance, check whether the provider is on your insurer's panel. Using non-panel providers may affect coverage or require pre-approval.

Building Forensic Readiness

The best time to think about digital forensics is before you need it.

Forensic readiness means configuring your environment to maximise the evidence available if an incident occurs:

- Enable and retain logs (beyond default retention periods)
- Ensure cloud services are configured for appropriate audit logging
- Document your environment (network diagrams, system inventories, data flows)
- Establish relationships with forensic providers before you need them
- Include forensic considerations in your incident response plan
- Test your ability to preserve evidence through tabletop exercises

Firms that invest in forensic readiness get faster, more conclusive investigations when incidents occur. The evidence is there. It just needs to be collected and analysed.

The Bottom Line

Digital forensics isn't about finding someone to blame or generating billable hours. It's about answering the questions that matter:

- What happened?
- What was affected?
- Who needs to know?
- How do we prevent it happening again?

For law firms, where client trust is everything, having clear answers to these questions isn't optional. It's the foundation for maintaining that trust through a crisis.

If you'd like to discuss forensic readiness for your firm, get in touch through our contact page or you can find out more here.