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Someone intercepts the security codes sent to verify your identity — by accessing your text messages, SIM-swapping your phone number, or using a device you've already trusted.
What You Might Notice
You stop receiving text messages or calls
Your SIM may have been swapped — the other person has transferred your number to their device.
Login codes arrive on a device you don't control
Security codes are going to a phone or email the other person has access to.
Your mobile service suddenly stops working
SIM swap attacks cause your phone to lose signal entirely.
What You Can Do
Switch to an authenticator app instead of SMS codes
Apps like Google Authenticator or Authy generate codes on your device, which is harder to intercept than text messages.
Set a PIN or password on your mobile account
Contact your carrier and add a security PIN to prevent SIM swaps.
Use a phone number the other person doesn't know
A separate prepaid number for two-factor authentication adds a layer of protection.
Important: This resource provides general information, not personal advice. Every situation is different. The actions suggested here may not be safe in your specific circumstances — particularly if the person causing harm could notice changes to your devices or accounts. Always consider your physical safety first.
If you need personalised support, contact 1800RESPECT (1800 737 732) or your local specialist domestic violence service. If you are in immediate danger, call 000.
Intercepting two-factor authentication codes through SIM swapping, access to victim's authenticator app, interception of SMS codes, or control of backup codes. Defeats security measures designed to protect accounts, enabling unauthorized access even when victim has changed passwords.
Authenticator App Security Use authenticator app on secure device rather than SMS-based 2FA.
SAFE-M-0051
SIM Security Controls Contact carrier to add SIM lock PIN and port-out protection.
SAFE-M-0052
Hardware Security Key Use hardware security key for highest-risk accounts.
Detection Indicators
ID
Detection Indicator
SAFE-D-0047
SIM Swap Indicators Sudden loss of mobile service may indicate SIM swap attack.
SAFE-D-0048
Unrequested 2FA Codes Receiving 2FA codes without initiating login attempts.
The TFA Matrix is a research framework under active development. Technique classifications, detection methods, and mitigations reflect current understanding and are subject to revision. This framework does not constitute forensic methodology, legal evidence standards, or clinical diagnostic criteria. Practitioners should apply professional judgement appropriate to their discipline and jurisdiction.