CVE-2021-1625Medium· 5.8▾ SunlitA vulnerability in the Zone-Based Policy Firewall feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to prevent the Zone-Based Policy Firewall from correctly classifying traffic. This vulnerability exists b…
▾ Sunlit zone — Low / medium · no exploitation signal
impact 31.9 · likelihood 0.2 · exploitation 0
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Exploit-prediction probability, daily snapshots since Sep 25.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CSAF
0.9%
A vulnerability in the Zone-Based Policy Firewall feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to prevent the Zone-Based Policy Firewall from correctly classifying traffic.
This vulnerability exists because ICMP and UDP responder-to-initiator flows are not inspected when the Zone-Based Policy Firewall has either Unified Threat Defense (UTD) or Application Quality of Experience (AppQoE) configured. An attacker could exploit this vulnerability by attempting to send UDP or ICMP flows through the network. A successful exploit could allow the attacker to inject traffic through the Zone-Based Policy Firewall, resulting in traffic being dropped because it is incorrectly classified or in incorrect reporting figures being produced by high-speed logging (HSL).
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is part of the September 2021 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication. ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74581"]
Cisco IOS XE Software Zone-Based Policy Firewall ICMP and UDP Inspection Vulnerability. Released 2021-09-22.
Affected:
Cisco has released software updates that address this vulnerability. https://software.cisco.com
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