Digital Forensics Fundamentals

It is the ordinary signature of a file arriving as a copy. The copy created a new file here, so the creation time is when it landed, while the modification time travelled with the content from its source.

First establish which comparison failed: the image against its recorded digest, or a fresh read of the source. On a dying drive the second failing is expected, since unreadable sectors differ between passes. Localise every difference to a logged error range.

You cannot collect it, only request it. File a preservation request first to stop the provider's own retention clock, then a precisely scoped export through the contractual channel, over-wide on the time window, and record the request and the receipt as chain of custody like any other evidence.

When something other than natural decay is destroying evidence. The ranking assumes only ordinary ageing; an intruder truncating logs, a retention edge, or a container about to be rescheduled makes a durable source the one most at risk.

Do not backfill the entry. Disclose the gap in writing, reconstruct the period from independent sources in a clearly labelled memo, and re-acquire the item under a clean chain if another source of it exists. Then decide what claims that artefact can still support alone.

Give him what the artefacts establish, what they are merely consistent with, and the one test that would settle the difference. Intent is almost never recorded in telemetry, and a sentence you cannot defend later discredits the findings you could.

Stop further loss, then tell counsel immediately. Freeze every comparable job, record exactly what was deleted and when, hunt for surviving second copies, and never quietly regenerate or backfill the missing period.

Show provenance, scope and shape: the policy object carrying the change, who edited it and when, that it reached every domain controller rather than one, that the loud subcategories went while logon auditing stayed, and that it predates every other indicator.

Fleet-wide uniformity favours a managed rollout but settles nothing on its own. Decide on artefact identity: the signer and Amcache hash of each binary, the task's author and principal, the account on the service-install record, and what the interpreter's Prefetch shows it read.

Two artefacts corroborate only if they can fail independently. Both rest on the same identity assertion, so they repeat one unresolved premise: who held the credential. They do jointly support a different claim — records were rendered and bytes left.

Expect metadata, not content. TRIM tells the drive those blocks are unused, so the controller unmaps them, reads return zeroes and carving finds nothing. Change-journal and MFT remnants can still prove a name, a size and a deletion time.

Smear. A memory image of a running host is written over minutes while the kernel keeps changing memory, so different parts of the image are from different moments. It has no single point in time and self-contradiction is expected, not corruption.

Settle custody, format and transfer, not their retention. Contract the right to receive raw collections with hashes into your own evidence store when a case opens, and keep the number of collections you retain long-term small rather than making the provider hold everything for years.

Mandate a small set you can actually sustain: one custody form used for every case, one lockable container with a single named keyholder and an access record, notes kept in a store whose timestamps you do not control, and a transfer arrangement agreed with your outside IR firm before an incident.

Legal owns the duty and the release; the platform team carries the cost. Bridge them with a hold register naming a responsible lawyer, scope and review date per matter, and negotiate scope rather than quietly letting holds lapse.

Assert only the indicator no ordinary process produces, and write the other two into the report as withdrawn with the explanations accounting for them. Separate observation from inference, state confidence, and leave the personnel decision to whoever owns it.

Give each ordering claim a bound. Same-clock events order reliably; cross-clock events only when the gap exceeds the offset uncertainty. Otherwise say the order cannot be established, and name what would settle it.