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UNAUTHORISED ACCESS • SYSTEMS • MALWARE • ATTRIBUTION

Computer Misuse & Cybercrime Offences

Computer Misuse Act cases often turn on authorisation and digital attribution: what access was permitted, what exceeded that permission, which device or user performed the act and what the defendant intended. Technical logs require legal context, not assumption.

KEY ANSWER

The position in brief

The Computer Misuse Act 1990 creates several offences, including unauthorised access to computer material and more serious forms involving further offending, impairment or tools/articles.

The central questions are usually what access was authorised, whether the defendant knew the access was unauthorised, and whether the prosecution can reliably attribute the act to that defendant.

Legal issues

The exact CMA section matters. Employer access, shared credentials, administrator rights, testing activity, malware, denial-of-service conduct and possession/supply of tools can engage different provisions.

Evidence that matters

Evidence may include server and authentication logs, IP records, device forensics, cloud records, source code, messages, credentials, access policies, audit logs and expert evidence.

Reasonable lines of enquiry

Enquiries may include preserving logs before retention periods expire, establishing user/device attribution, reviewing access permissions, examining shared credentials and independent forensic review of alleged malware or system impairment.

What happens next

Cybercrime cases may involve device seizure, specialist forensic examination and cross-border platform or server evidence. Serious cases can proceed to the Crown Court.

Immediate steps

Preserve logs, policies, permissions and device information. Do not alter systems or wipe devices after learning of an investigation. Record the scope of any work or access authority.

What should you send us?

Send the allegation/charge, system details, access policies, logs, forensic reports, device/account information, police papers and next date.

Legal information from Theodorous. The law and procedure can change and the application of the law depends on the facts. This guide is general information, not advice on your individual case.

HOW WE CAN HELP

What Theodorous can do

We can identify the applicable CMA offence, analyse authorisation and attribution, coordinate forensic expert review, advise at interview and prepare pre-charge or Crown Court defence.

Primary legal sources

NEXT STEP

Discuss a computer-misuse investigation

Send the system, access and forensic evidence for a focused cybercrime review.

Discuss a computer-misuse investigation

FREQUENTLY ASKED QUESTIONS

Questions about this issue

Is using someone else’s password automatically a Computer Misuse Act offence?

Not automatically. The legal issue is whether the access was unauthorised and whether the defendant knew that, assessed against the factual permission and system context.

Can employer permissions matter?

Yes. The scope of employment or administrator authority can be central to whether access was unauthorised.

Can digital attribution be challenged?

Yes. IP addresses, accounts and devices do not always prove who performed an act without supporting evidence.