On Juniper Networks MX Series and EX9200 Series platforms with Trio-based MPC (Modular Port Concentrator) where Integrated Routing and Bridging (IRB) interface is configured and it is mapped to a VPLS instance or a Bridge-Domain, certain network events at Customer Edge (CE) device may cause memory leak in the MPC which can cause an out of memory and MPC restarts. When this issue occurs, there will be temporary traffic interruption until the MPC is restored. An administrator can use the following CLI command to monitor the status of memory usage level of the MPC: user@device> show system resource-monitor fpc FPC Resource Usage Summary Free Heap Mem Watermark : 20 % Free NH Mem Watermark : 20 % Free Filter Mem Watermark : 20 % * - Watermark reached Slot # % Heap Free RTT Average RTT 1 87 PFE # % ENCAP mem Free % NH mem Free % FW mem Free 0 NA 88 99 1 NA 89 99 When the issue is occurring, the value of “% NH mem Free” will go down until the MPC restarts. This issue affects MX Series and EX9200 Series with Trio-based PFEs (Packet Forwarding Engines). Please refer to https://kb.juniper.net/KB25385 for the list of Trio-based PFEs. This issue affects Juniper Networks Junos OS on MX Series, EX9200 Series: 17.3R3-S8; 17.4R3-S2; 18.2R3-S4, 18.2R3-S5; 18.3R3-S2, 18.3R3-S3; 18.4 versions starting from 18.4R3-S1 and later versions prior to 18.4R3-S6; 19.2 versions starting from 19.2R2 and later versions prior to 19.2R3-S1; 19.4 versions starting from 19.4R2 and later versions prior to 19.4R2-S3, 19.4R3; 20.2 versions starting from 20.2R1 and later versions prior to 20.2R1-S3, 20.2R2. This issue does not affect Juniper Networks Junos OS: 18.1, 19.1, 19.3, 20.1.
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 | 17.3-r3-s8 (including) | 17.3-r3-s8 (including) |
| Junos | Juniper | 17.4-r3-s2 (including) | 17.4-r3-s2 (including) |
| Junos | Juniper | 18.2-r3-s4 (including) | 18.2-r3-s4 (including) |
| Junos | Juniper | 18.2-r3-s5 (including) | 18.2-r3-s5 (including) |
| Junos | Juniper | 18.3-r3-s2 (including) | 18.3-r3-s2 (including) |
| Junos | Juniper | 18.3-r3-s3 (including) | 18.3-r3-s3 (including) |
| Junos | Juniper | 18.4-r3-s1 (including) | 18.4-r3-s1 (including) |
| Junos | Juniper | 18.4-r3-s2 (including) | 18.4-r3-s2 (including) |
| Junos | Juniper | 18.4-r3-s3 (including) | 18.4-r3-s3 (including) |
| Junos | Juniper | 18.4-r3-s4 (including) | 18.4-r3-s4 (including) |
| Junos | Juniper | 18.4-r3-s5 (including) | 18.4-r3-s5 (including) |
| Junos | Juniper | 19.2-r2 (including) | 19.2-r2 (including) |
| Junos | Juniper | 19.2-r3 (including) | 19.2-r3 (including) |
| Junos | Juniper | 19.4-r2 (including) | 19.4-r2 (including) |
| Junos | Juniper | 19.4-r2-s1 (including) | 19.4-r2-s1 (including) |
| Junos | Juniper | 19.4-r2-s2 (including) | 19.4-r2-s2 (including) |
| Junos | Juniper | 20.2-r1 (including) | 20.2-r1 (including) |
| Junos | Juniper | 20.2-r1-s1 (including) | 20.2-r1-s1 (including) |
| Junos | Juniper | 20.2-r1-s2 (including) | 20.2-r1-s2 (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.