Secure Calling and Spam mitigation

Publisher

Cisco Systems, Inc. (help.webex.com)

URL

https://help.webex.com/en-us/article/8j6te9/Secure-Calling-and-Spam-mitigation

Published

2026-09-03

Updated

unknown

Accessed

2026-09-16

HTTP status

200

License

Cisco proprietary documentation, all rights reserved; no-redistribution; short excerpts and locators only

Source notes citing this source

• Webex Calling's call indication features and Caller ID settings apply only to locations in the United States and Canada. in context
• Webex Calling shows Potential Fraud when verstat is TN-Validation-Failed, and Possible Spam when verstat is No-TN-Validation, missing, or TN-Validation-Passed with C attestation. in context
• The spam settings in Webex Calling and Teams govern how the tenant's inbound calls are labeled or blocked; they do not change how terminating carriers label the tenant's outbound calls, which is decided by the called party's carrier and its analytics vendor. inferred in context
• The Webex Calling setting 'Block calls that failed Caller ID validation' is disabled by default. in context
• Webex Calling can integrate a certified caller reputation provider (Mutare) that scores inbound PSTN calls from 0.0 to 5.0 and can block, CAPTCHA-challenge or allow them; it is available to customers headquartered in North America and needs a subscription with the provider. in context
• Webex Calling's call indication features and Caller ID settings apply only to Webex Calling locations in the United States and Canada. in context
• Webex Calling maps inbound STIR/SHAKEN verstat to user-facing labels: TN-Validation-Passed with A attestation shows 'Verified Caller', TN-Validation-Failed shows 'Potential Fraud', and No-TN-Validation shows 'Possible Spam'. in context
• Webex Calling shows Possible Spam, not Verified Caller, for calls with verstat TN-Validation-Passed and attestation B. in context
• When an administrator blocks calls that fail STIR/SHAKEN validation, Webex Calling does not offer the call to the user, releases it with cause 603 and logs it in the user's call history as blocked. in context
• Webex Calling shows Potential Fraud when verstat is TN-Validation-Failed. in context
• Mutare, a certified caller reputation provider for Webex Calling, returns a reputation score and can return a rule action of allow, block or CAPTCHA for incoming PSTN calls. in context
• Webex Calling spam call indications apply only to Webex Calling locations in the United States and Canada; other locations present calls normally whatever the settings. in context
• Webex Calling shows Verified Caller for calls with verstat TN-Validation-Passed and attestation A. in context
• Webex Calling reads the verstat parameter on incoming calls and shows a caller-ID disposition on Cisco clients: Verified Caller, Possible Spam or Potential Fraud. in context
• In Webex Calling's mapping from verification result to client display, a call whose validation passed is shown as Verified Caller when the attestation is A or not provided and as Possible Spam when the attestation is B or C; a failed validation is shown as Potential Fraud; and no validation, or no verstat parameter at all, is shown as Possible Spam. in context
• The Control Hub setting that blocks calls failing caller identity validation is disabled by default, and Cisco states that when it is enabled such calls are not routed to the user's endpoints while the calling number is still added to the called user's call history. in context
• Webex Calling sends the called number to the reputation provider along with the caller information, so an administrator can configure rules in the provider's portal that apply different screening treatments by destination, and Cisco states that the provider can return an allow, block or CAPTCHA action based on the calling number, the called number or a combination while the reputation score itself remains based on the calling number. in context
• Webex Calling integrates Certified Calling Reputation Providers that assess incoming PSTN calls in real time and return an allow, block or CAPTCHA action, and Cisco states the integration is available for customers headquartered in North America through the certified provider Mutare. in context
• Cisco clients that support Unified Call History show an icon for the caller identity disposition in the call history record, and Cisco states that the Webex App displays the attestation text and the icon while Multiplatform phones display only the icon. in context
• Cisco states that for mid-call features including call transfer, call park, call pickup, call forwarding and caller identity, the caller identity disposition is based on the verstat value processed on the initial call leg, and that when an incoming call to a Webex Calling user is forwarded and the calling number changes the disposition is still decided by the verstat in the incoming call request. in context
• Cisco states that the call indication features and the caller identity settings apply only to Webex Calling locations in the United States and Canada, and that other locations see calls presented normally regardless of the caller identity settings. in context
• Cisco requires organisations in the United States and Canada using on-premises PSTN through a Local Gateway or Cisco Unified Border Element to configure a SIP copy list covering the From, P-Asserted-Identity and P-Attestation-Indicator headers together with 9 SIP profile rules, in order to pass verstat information through to Webex Calling, and states that applying the configuration when the service provider does not send the parameter does not affect calls. in context
• Where the PSTN provider does not send verstat information in an incoming call, Cisco instructs the administrator not to change the default of the setting presenting calls from unverified callers as normal, because disabling it would show the Possible Spam indication to users on every such call. in context
• Webex Calling marks an on-net call between Webex Calling users and an on-net call from a Unified Communications Manager user to a Webex Calling user as a verified user with an icon, classifying the Unified CM case by whether the caller identity matches the configured enterprise dial plan, and Cisco states that a call from a Webex Calling user to an on-premises Unified CM user carries no indication on the Unified CM client. in context
• Cisco states that spam detection is supported on the Webex App desktop and mobile at version 42.5 or higher and on 6800, 7800, 8800 and 9800 Multiplatform phones at firmware version 11.3.7 or higher. in context
• Cisco states that the SHAKEN attestation levels let an originating service provider attest its relationship to the calling number: A means the provider can attest that the caller has the right to use the phone number as the caller identity, B means the customer is known but it is unknown whether they have the right to use the caller identity, and C means the call meets neither requirement, for which Cisco's example is an international call. in context
• The Control Hub setting presenting calls from unverified callers as normal calls is enabled by default, so unverified calls reach endpoints with no indication, and Cisco states that an organisation whose PSTN service provider has enabled STIR/SHAKEN can disable it, after which unverified callers display as Possible Spam. in context
• Cisco states that terminating service providers convey verification results in the verstat parameter of the SIP P-Asserted-Identity header, with 3 values: TN-Validation-Passed for a successful validation carrying an A, B or C attestation, TN-Validation-Failed where the caller could not be verified, and No-TN-Validation for a verification failure for other reasons such as a malformed E.164 number. in context

Cite this source record

APA

WarmTransfer. (2026, September 3). Secure Calling and Spam mitigation. WarmTransfer. https://warmtransfer.net/knowledge/sources/cisco-help-8j6te9-secure-calling-spam

BibTeX

@misc{warmtransfer-cisco-help-8j6te9-secure-calling-spam,
  title  = {Secure Calling and Spam mitigation},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/sources/cisco-help-8j6te9-secure-calling-spam},
  note   = {Cisco Systems, Inc. (help.webex.com), accessed 2026-09-16}
}