3.3.1.1 PIM Accept-Register

Information

PIM Accept-register is a security feature designed to control which sources and groups are allowed to register with the Rendezvous Point (RP). This feature works alongside the RP configuration and includes an access list (ACL) option to filter sources and groups. The ACL specifies rules for permitting or denying traffic based on source and group addresses. When configured, this functionality ensures that only authorized multicast sources and groups are registered with the RP, enhancing security and preventing unauthorized multicast traffic.

By associating an ACL with a PIM router, administrators can filter and control the registration of multicast sources and groups. Without such control, unauthorized or malicious sources could register with the RP, potentially leading to resource misuse or network disruption. The PIM Accept-register feature performs a lookup to check if the source (S) and group (G) in a packet match the permitted list defined in the ACL. If there is no match or if a deny rule is encountered, the packet is dropped immediately, and a register stop message is sent. This mechanism ensures that only permitted multicast traffic is processed, enhancing the network's security and operational efficiency.

Solution

Sample PIM Accept-Register configuration -

switch(config)# access-list ip <pim_reg_acl>
switch(config-acl-ip)# 10 permit any <20.1.1.1> <225.1.1.2>
switch(config-acl-ip)# 20 deny any <30.1.1.1> <225.1.1.3>
switch(config-acl-ip)# exit
switch(config)# router pim
switch(config-pim)# accept-register access-list <pim_reg_acl>
switch(config-pim)# exit
switch(config)# access-list ipv6 <pim_regv6_acl>
switch(config-acl-ipv6)# 10 permit any <20.::1> <ff1e::1>
switch(config-acl-ipv6)# 20 deny any <30::1> <ff1e::3>
witch(config-acl-ipv6)# exit
switch(config)# router pim6
switch(config-pim6)# accept-register access-list <pim_regv6_acl>
switch(config-pim6)# exit

Impact:

Packets matching the ACL permit rules are processed normally, while denied or unmatched packets are immediately dropped with a register stop message sent. This prevents unauthorized or malicious traffic from reaching the RP, enhancing network security and efficiency.

See Also

https://workbench.cisecurity.org/benchmarks/24202

Item Details

Category: ACCESS CONTROL, SECURITY ASSESSMENT AND AUTHORIZATION, MEDIA PROTECTION, SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|AC-3, 800-53|AC-5, 800-53|AC-6, 800-53|CA-7, 800-53|MP-2, 800-53|SC-4, CSCv7|14.6, CSCv7|14.7

Plugin: ArubaOS

Control ID: 553baa8942fd7105adfb8e1e425ef0e3cdf94be497a1a1213f317ff6c8087c2c