Vulnerability Name:

CVE-2021-34697 (CCN-209911)

Assigned:2021-09-21
Published:2021-09-21
Updated:2021-10-05
Summary:A vulnerability in the Protection Against Distributed Denial of Service Attacks feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to conduct denial of service (DoS) attacks to or through the affected device. This vulnerability is due to incorrect programming of the half-opened connections limit, TCP SYN flood limit, or TCP SYN cookie features when the features are configured in vulnerable releases of Cisco IOS XE Software. An attacker could exploit this vulnerability by attempting to flood traffic to or through the affected device. A successful exploit could allow the attacker to initiate a DoS attack to or through an affected device.
CVSS v3 Severity:8.6 High (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H)
7.5 High (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/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): None
Availibility (A): High
5.8 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L)
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:N/A:L/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): None
Availibility (A): Low
CVSS v2 Severity:5.0 Medium (CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Partial
5.0 Medium (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Partial
Vulnerability Type:CWE-665
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2021-34697

Source: XF
Type: UNKNOWN
cisco-cve202134697-dos(209911)

Source: CCN
Type: Cisco Security Advisory cisco-sa-zbfw-tguGuYq
Cisco IOS XE Software Protection Against Distributed Denial of Service Attacks Feature Vulnerability

Source: CISCO
Type: Vendor Advisory
20210922 Cisco IOS XE Software Protection Against Distributed Denial of Service Attacks Feature Vulnerability

Vulnerable Configuration:Configuration 1:
  • cpe:/o:cisco:ios_xe:*:*:*:*:*:*:*:* (Version >= 17.3.1 and < 17.3.3)

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

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