Vulnerability Name:

CVE-2021-0239 (CCN-199996)

Assigned:2020-10-27
Published:2021-04-14
Updated:2021-04-27
Summary:In Juniper Networks Junos OS Evolved, receipt of a stream of specific genuine Layer 2 frames may cause the Advanced Forwarding Toolkit (AFT) manager process (Evo-aftmand), responsible for handling Route, Class-of-Service (CoS), Firewall operations within the packet forwarding engine (PFE) to crash and restart, leading to a Denial of Service (DoS) condition. By continuously sending this specific stream of genuine Layer 2 frames, an attacker can repeatedly crash the PFE, causing a sustained Denial of Service (DoS). This issue affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R1-EVO. This issue does not affect Junos OS versions.
CVSS v3 Severity:6.5 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
5.7 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
6.5 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
5.7 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
CVSS v2 Severity:6.1 Medium (CVSS v2 Vector: AV:A/AC:L/Au:N/C:N/I:N/A:C)
Exploitability Metrics:Access Vector (AV): Adjacent_Network
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Complete
6.1 Medium (CCN CVSS v2 Vector: AV:A/AC:L/Au:N/C:N/I:N/A:C)
Exploitability Metrics:Access Vector (AV): Adjacent_Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Complete
Vulnerability Type:CWE-754
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2021-0239

Source: XF
Type: UNKNOWN
juniper-cve20210239-dos(199996)

Source: CCN
Type: Juniper Networks Security Bulletin JSA11134
Junos OS Evolved: Denial of Service due to receipt of specific genuine layer 2 frames. (CVE-2021-0239)

Source: MISC
Type: Vendor Advisory
https://kb.juniper.net/JSA11134

Vulnerable Configuration:Configuration 1:
  • cpe:/o:juniper:junos_os_evolved:20.4:r1:*:*:*:*:*:*

    • Configuration CCN 1:
  • cpe:/h:juniper:junos:-:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
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