Summary

Security Advisory ID : BSA-2017-225

Component : ntp

Revision : 1.0: Interim

When ntpd receives a server response on a socket that corresponds to a different interface than was used for the request, the peer structure is updated to use the interface for new requests. If ntpd is running on a host with multiple interfaces in separate networks and the operating system doesn't check source address in received packets (e.g. rp_filter on Linux is set to 0), an attacker that knows the address of the source can send a packet with spoofed source address which will cause ntpd to select wrong interface for the source and prevent it from sending new requests until the list of interfaces is refreshed, which happens on routing changes or every 5 minutes by default. If the attack is repeated often enough (once per second), ntpd will not be able to synchronize with the source.

Affected Products

Products Confirmed Not Vulnerable

Brocade Fabric OS, Brocade FastIron OS, Brocade NetIron OS, Brocade Network Advisor, Brocade Network OS, Brocade SDN Controller, Brocade ServerIron ADX, Brocade SLX-OS, Brocade Virtual ADX, BrocadeVirtual Traffic Manager: Software, and Brocade Virtual Web Application Firewall are confirmed not affected by this vulnerability.

Workaround

There are no workarounds that address this vulnerability.
 

Revision History