The advertising of these routes went on for almost an hour, according to a blog post by Andree Toonk, the founder of BGPmon, a service that is owned by Cisco and monitors BGP routing information in real-time. It affected 8870 network prefixes belonging to almost 200 autonomous systems.
This phenomenon, which is known as BGP hijacking, can occur because of mistakes by operators or can be deliberately effected in order for the operator carrying out the hijack to capture traffic for nefarious reasons.
Toonk said in a tweet early on Monday morning AEDT: "For what it's worth: I don't think they intended to announce this to the rest of the world (hijack).
He said he had seen a similar incident involving the same ISP a few years ago.
For what it's worth: I don't think they intended to announce this to the rest of the world (hijack). What we saw here, by accident, is that they treat these (new more specific) prefixes special inside their network. Likely for some kind of "Traffic Engineering" reason. https://t.co/oIogm64YA0— Andree Toonk (@atoonk) April 5, 2020
The incident was reported twice on the BGPmon twitter account, leading to an over-excited ZDNet reporter jumping the gun and claiming there had been two hijacking incidents.
Given the existing climate in the US as far as Russia is concerned, the ZDNet report called the redirection of traffic "suspicious", even though Toonk himself was unable to decide whether the hijack was deliberate or not.
Every ISP advertises the routes for which it is authorised to carry traffic. When it comes to inter-carrier routing, carriers often need to send traffic to each other.
BGP is the protocol through which this is managed, allowing each carrier to broadcast what IP address ranges or prefixes should be sent to them.
But since the security of the protocol is not very good, one carrier can announce incorrect prefixes; this effectively means taking over the address ranges of another provider and taking them down.
It means that a carrier can switch off a number of other providers if they wished to do so.
In November 2018, Telstra stuffed up the routes it advertised through the BGP and took down a sizeable part of the Internet in Australia. The telco later claimed that a third party was responsible for the stuff-up.
The same week, Google was affected by network issues which turned out to be due to an ISP in Africa broadcasting wrong routes. MainOne, the ISP which was responsible for the error, said later that it was due to a misconfiguration on its BGP filters and the error lasted for 74 minutes.