A sustained sequence of different types of normal transit traffic can trigger a high CPU consumption denial of service condition in the Junos OS register and schedule software interrupt handler subsystem when a specific command is issued to the device. This affects one or more threads and conversely one or more running processes running on the system. Once this occurs, the high CPU event(s) affects either or both the forwarding and control plane. As a result of this condition the device can become inaccessible in either or both the control and forwarding plane and stops forwarding traffic until the device is rebooted. The issue will reoccur after reboot upon receiving further transit traffic. Score: 5.7 MEDIUM (CVSS:3.0/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H) For network designs utilizing layer 3 forwarding agents or other ARP through layer 3 technologies, the score is slightly higher. Score: 6.5 MEDIUM (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H) If the following entry exists in the RE message logs then this may indicate the issue is present. This entry may or may not appear when this issue occurs. /kernel: Expensive timeout(9) function: Affected releases are Juniper Networks Junos OS: 12.1X46 versions prior to 12.1X46-D50; 12.3X48 versions prior to 12.3X48-D30; 12.3R versions prior to 12.3R12-S7; 14.1 versions prior to 14.1R8-S4, 14.1R9; 14.1X53 versions prior to 14.1X53-D30, 14.1X53-D34; 14.2 versions prior to 14.2R8; 15.1 versions prior to 15.1F6, 15.1R3; 15.1X49 versions prior to 15.1X49-D40; 15.1X53 versions prior to 15.1X53-D31, 15.1X53-D33, 15.1X53-D60. No other Juniper Networks products or platforms are affected by this issue.
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.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Junos | Juniper | 12.1x46 (including) | 12.1x46 (including) |
| Junos | Juniper | 12.1x46-d10 (including) | 12.1x46-d10 (including) |
| Junos | Juniper | 12.1x46-d15 (including) | 12.1x46-d15 (including) |
| Junos | Juniper | 12.1x46-d20 (including) | 12.1x46-d20 (including) |
| Junos | Juniper | 12.1x46-d25 (including) | 12.1x46-d25 (including) |
| Junos | Juniper | 12.1x46-d30 (including) | 12.1x46-d30 (including) |
| Junos | Juniper | 12.1x46-d35 (including) | 12.1x46-d35 (including) |
| Junos | Juniper | 12.1x46-d40 (including) | 12.1x46-d40 (including) |
| Junos | Juniper | 12.1x46-d45 (including) | 12.1x46-d45 (including) |
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:
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.