Specific IPv6 DHCP packets received by the jdhcpd daemon will cause a memory resource consumption issue to occur on a Junos OS device using the jdhcpd daemon configured to respond to IPv6 requests. Once started, memory consumption will eventually impact any IPv4 or IPv6 request serviced by the jdhcpd daemon, thus creating a Denial of Service (DoS) condition to clients requesting and not receiving IP addresses. Additionally, some clients which were previously holding IPv6 addresses will not have their IPv6 Identity Association (IA) address and network tables agreed upon by the jdhcpd daemon after the failover event occurs, which leads to more than one interface, and multiple IP addresses, being denied on the client. Affected releases are Juniper Networks Junos OS: 17.4 versions prior to 17.4R2; 18.1 versions prior to 18.1R2.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Junos | Juniper | 17.4 (including) | 17.4r2 (excluding) |
| Junos | Juniper | 18.1 (including) | 18.1r2 (excluding) |
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.