Check for malicious email forwarding rules

The short answer: Mailbox rules are legitimate automation features that can quietly copy, delete or hide security messages. They are valuable persistence tools after an account compromise.

A password change may leave mailbox access behind

The useful move is to separate what the claimant controls from evidence you can obtain independently. Names, logos, caller ID, screenshots and a polished page can all be copied. A saved telephone number, a typed official address, a known colleague or a protected transaction route changes the channel instead of merely inspecting the same claim again.

Risk also depends on consequence. Reading a public page is different from granting remote access, sending an identity document or approving an irreversible payment. As the cost of error rises, require stronger verification and prefer a step you can undo.

Warning signals to assess together

These clues become useful when they form a pattern. Treat each one as a prompt to verify, not as a verdict by itself.

• Security messages vanish or appear already read

  Pair this observation with a separate check: Inspect forwarding, filters and delegated access.

• Unknown forwarding addresses or filters

  Pair this observation with a separate check: Revoke sessions and connected apps.

• Sent messages or login sessions you do not recognise

  Pair this observation with a separate check: Change credentials and strengthen authentication.

Do not use one clue as a verdict: A rule may have a normal explanation. Preserve its details before deleting it if the account is part of a formal investigation.

A related recovery control appears in the first-hour account takeover plan, especially when one account or channel can unlock another.

Remove mailbox persistence after an account compromise

Keep the verification route separate from any contact detail or instruction supplied in the questionable message.

• Inspect forwarding, filters and delegated access

  This step tests the related concern: Security messages vanish or appear already read.

• Revoke sessions and connected apps

  This step tests the related concern: Unknown forwarding addresses or filters.

• Change credentials and strengthen authentication

  This step tests the related concern: Sent messages or login sessions you do not recognise.

If access may already be exposed, the breach response builder can put containment and recovery steps in a safer order.

Decide what to do after verification

If the independent channel confirms the identity and request, ask whether the proposed method still gives you a record and recourse. Legitimate people and organisations should tolerate a proportionate verification step. Resistance, secrecy or a demand to bypass normal controls is new evidence, not an inconvenience to ignore.

If the evidence remains mixed, reduce exposure: do not send original documents when a redacted copy is enough, do not pay a deposit before verifying authority, and do not approve access broader than the task requires. “Not yet” is a valid decision when the missing fact matters.

What this verification cannot establish

This guide cannot authenticate a specific person, account, website or transaction. Interfaces and attack methods change, and legitimate situations sometimes contain unusual details. For an active loss, account compromise or safety threat, contact the relevant institution or official reporting service through a verified route.