For a little over 12 hours on 26-27 July, a network operated by Russia’s Rostelecom started announcing routes for part of Apple’s network. The effect was that Internet users in parts of the Internet trying to connect to Apple’s services may have been redirected to the Rostelecom network. Apple Engineering appears to have been successful in reducing the impact, and eventually Rostelecom stopped sending the false route announcements. This event demonstrated, though, how Apple could further protect its networks by using Route Origin Authorizations (ROAs).
We are not aware of any information yet from Apple that indicates what, if any, Apple services were affected. We also have not seen any information from Rostelecom about whether this was a configuration mistake or a deliberate action.
Let’s dig into what we know so far about what happened, and how Route Origin Authorization (ROA) can help prevent these kinds of events.
Around 21:25 UTC On 26 July 2022, Rostelecom’s AS12389 network started announcing 17.70.96.0/19. This prefix is part of Apple’s 17.0.0.0/8 block; usually, Apple only announces the larger 17.0.0.0/9 block and not this shorter prefix length.
When the routes a network is announcing are not covered by valid Route Origin Authorization (ROA), the only option during a route hijack is to announce more specific routes. This is exactly what Apple Engineering did today; upon learning about the hijack, it started announcing 17.70.96.0/21 to direct traffic toward AS714.
RIPE RIS data, captured via pybgpkit tool
It is not clear what AS12389 was doing, as it announced the same prefix at the same time with AS prepend as well.
RIPE RIS data, captured via pybgpkit tool
In the absence of any credible data to filter out any possible hijack attempts, the route announced by AS12389 was propagated across the globe. The incident was picked up by BGPstream.com (Cisco Works) and GRIP Internet Intel (GA Tech).
Apple must have received the alert too. Whatever mitigation techniques they tried didn’t stop the Rostelecom announcement and so Apple announced the more specific route. As per the BGP path selection process, the longest-matching route is preferred first. Prefix length supersedes all other route attributes. Apple started announcing 17.70.96.0/21 to direct traffic toward AS714.
