Vulnerability Name:

CVE-2021-1625 (CCN-209908)

Assigned:2020-11-13
Published:2021-09-21
Updated:2021-10-05
Summary: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).
CVSS v3 Severity:5.8 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N)
5.1 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Changed
Impact Metrics:Confidentiality (C): None
Integrity (I): Low
Availibility (A): None
5.8 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N)
5.1 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Changed
Impact Metrics:Confidentiality (C): None
Integrity (I): Low
Availibility (A): None
CVSS v2 Severity:4.3 Medium (CVSS v2 Vector: AV:N/AC:M/Au:N/C:N/I:P/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Medium
Authentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): Partial
Availibility (A): None
5.0 Medium (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:P/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): Partial
Availibility (A): None
Vulnerability Type:CWE-Other
Vulnerability Consequences:Bypass Security
References:Source: MITRE
Type: CNA
CVE-2021-1625

Source: XF
Type: UNKNOWN
cisco-cve20211625-sec-bypass(209908)

Source: CCN
Type: Cisco Security Advisory cisco-sa-zbfw-pP9jfzwL
Cisco IOS XE Software Zone-Based Policy Firewall ICMP and UDP Inspection Vulnerability

Source: CISCO
Type: Vendor Advisory
20210922 Cisco IOS XE Software Zone-Based Policy Firewall ICMP and UDP Inspection Vulnerability

Vulnerable Configuration:Configuration 1:
  • cpe:/o:cisco:ios_xe:*:*:*:*:*:*:*:* (Version < 17.3.2)

    • Configuration CCN 1:
  • cpe:/o:cisco:ios_xe_software:*:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    cisco ios xe *
    cisco ios xe software *