Receipt of specially crafted UDP/IP packets over MPLS may be able to bypass a stateless firewall filter. The crafted UDP packets must be encapsulated and meet a very specific packet format to be classified in a way that bypasses IP firewall filter rules. The packets themselves do not cause a service interruption (e.g. RPD crash), but receipt of a high rate of UDP packets may be able to contribute to a denial of service attack. This issue only affects processing of transit UDP/IP packets over MPLS, received on an interface with MPLS enabled. TCP packet processing and non-MPLS encapsulated UDP packet processing are unaffected by this issue. Affected releases are Juniper Networks Junos OS: 12.1X46 versions prior to 12.1X46-D76; 12.3 versions prior to 12.3R12-S10; 12.3X48 versions prior to 12.3X48-D66, 12.3X48-D70; 14.1X53 versions prior to 14.1X53-D47; 15.1 versions prior to 15.1F6-S10, 15.1R4-S9, 15.1R6-S6, 15.1R7; 15.1X49 versions prior to 15.1X49-D131, 15.1X49-D140; 15.1X53 versions prior to 15.1X53-D59 on EX2300/EX3400; 15.1X53 versions prior to 15.1X53-D67 on QFX10K; 15.1X53 versions prior to 15.1X53-D233 on QFX5200/QFX5110; 15.1X53 versions prior to 15.1X53-D471, 15.1X53-D490 on NFX; 16.1 versions prior to 16.1R3-S8, 16.1R4-S9, 16.1R5-S4, 16.1R6-S3, 16.1R7; 16.2 versions prior to 16.2R1-S6, 16.2R2-S5, 16.2R3; 17.1 versions prior to 17.1R1-S7, 17.1R2-S7, 17.1R3; 17.2 versions prior to 17.2R1-S6, 17.2R2-S4, 17.2R3; 17.2X75 versions prior to 17.2X75-D100; 17.3 versions prior to 17.3R1-S4, 17.3R2-S2, 17.3R3; 17.4 versions prior to 17.4R1-S3, 17.4R2; 18.1 versions prior to 18.1R2; 18.2X75 versions prior to 18.2X75-D5.
The product does not properly control the allocation and maintenance of a limited resource.
| 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) |
| Junos | Juniper | 12.1x46-d50 (including) | 12.1x46-d50 (including) |
| Junos | Juniper | 12.1x46-d55 (including) | 12.1x46-d55 (including) |
| Junos | Juniper | 12.1x46-d60 (including) | 12.1x46-d60 (including) |
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.