CVE Vulnerabilities


Uncontrolled Resource Consumption

Published: Jul 15, 2021 | Modified: Oct 25, 2021
CVSS 3.x
CVSS 2.x
3.3 LOW

An Uncontrolled Resource Consumption vulnerability in the ARP daemon (arpd) and Network Discovery Protocol (ndp) process of Juniper Networks Junos OS Evolved allows a malicious attacker on the local network to consume memory resources, ultimately resulting in a Denial of Service (DoS) condition. Link-layer functions such as IPv4 and/or IPv6 address resolution may be impacted, leading to traffic loss. The processes do not recover on their own and must be manually restarted. Changes in memory usage can be monitored using the following shell commands (header shown for clarity): user@router:/var/log# ps aux | grep arpd USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 31418 59.0 0.7 5702564 247952 ? xxx /usr/sbin/arpd –app-name arpd -I object_select –shared-objects-mode 3 user@router:/var/log# ps aux | grep arpd USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 31418 49.1 1.0 5813156 351184 ? xxx /usr/sbin/arpd –app-name arpd -I object_select –shared-objects-mode 3 Memory usage can be monitored for the ndp process in a similar fashion: user@router:/var/log# ps aux | grep ndp USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 14935 0.0 0.1 5614052 27256 ? Ssl Jun15 0:17 /usr/sbin/ndp -I no_tab_chk,object_select –app-name ndp –shared-obje user@router:/var/log# ps aux | grep ndp USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 14935 0.0 0.1 5725164 27256 ? Ssl Jun15 0:17 /usr/sbin/ndp -I no_tab_chk,object_select –app-name ndp –shared-obje This issue affects Juniper Networks Junos OS Evolved: 19.4 versions prior to 19.4R2-S3-EVO; 20.1 versions prior to 20.1R2-S4-EVO; all versions of 20.2-EVO. This issue does not affect Juniper Networks Junos OS Evolved versions prior to 19.4R2-EVO.


The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.

Affected Software

Name Vendor Start Version End Version
Junos_os_evolved Juniper 19.4-r1 (including) 19.4-r1 (including)
Junos_os_evolved Juniper 19.4-r2 (including) 19.4-r2 (including)
Junos_os_evolved Juniper 19.4-r2-s1 (including) 19.4-r2-s1 (including)
Junos_os_evolved Juniper 19.4-r2-s2 (including) 19.4-r2-s2 (including)
Junos_os_evolved Juniper 20.1 (including) 20.1 (including)
Junos_os_evolved Juniper 20.1-r1 (including) 20.1-r1 (including)
Junos_os_evolved Juniper 20.1-r1-s1 (including) 20.1-r1-s1 (including)
Junos_os_evolved Juniper 20.1-r2 (including) 20.1-r2 (including)
Junos_os_evolved Juniper 20.1-r2-s1 (including) 20.1-r2-s1 (including)
Junos_os_evolved Juniper 20.1-r2-s2 (including) 20.1-r2-s2 (including)
Junos_os_evolved Juniper 20.1-r2-s3 (including) 20.1-r2-s3 (including)
Junos_os_evolved Juniper 20.2 (including) 20.2 (including)

Extended Description

Limited resources include memory, file system storage, database connection pool entries, and CPU. If an attacker can trigger the allocation of these limited resources, but the number or size of the resources is not controlled, then the attacker could cause a denial of service that consumes all available resources. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system. There are at least three distinct scenarios which can commonly lead to resource exhaustion:

Resource exhaustion problems are often result due to an incorrect implementation of the following situations:

Potential Mitigations

  • Mitigation of resource exhaustion attacks requires that the target system either:

  • The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.

  • The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.