By default (silent-discard untrusted enabled) CUBE silently drops SIP requests from untrusted sources without sending any response.

Checked 2026-09-25

Vendor
Cisco
Product
Cisco Unified Border Element (CUBE)
Subsystem
TDoS Attack Mitigation
Deployment
on-premises
Region
not restricted
Release range
Cisco IOS XE 17.6 onwards
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP scanning and telephony denial of service: source note sip-scanning-tdos-cube-silent-discard-default. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-scanning-tdos-cube-silent-discard-default

BibTeX

@misc{warmtransfer-claim-sip-scanning-tdos-cube-silent-discard-default,
  title  = {SIP scanning and telephony denial of service: source note sip-scanning-tdos-cube-silent-discard-default},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-scanning-tdos-cube-silent-discard-default},
  note   = {Source note sip-scanning-tdos-cube-silent-discard-default, checked 2026-09-25}
}

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