DESCRIPTION LAST UPDATED: 2023-12-07
DEFAULT SECURITY LEVEL: HIGH
Introduction
This report identifies open Border Gateway Protocol (BGP) servers on port 179/TCP. As explained in wikipedia, BGP is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the Internet. The current BGP protocol specification can be found in RFC 4271.
Please refer to RFC7454 BGP Operations and Security for best practice guidance. Specifically:
4. Protection of the BGP Speaker
The BGP speaker needs to be protected from attempts to subvert the
BGP session. This protection SHOULD be achieved by an Access Control
List (ACL) that would discard all packets directed to TCP port 179 on
the local device and sourced from an address not known or permitted
to become a BGP neighbor. Experience has shown that the natural
protection TCP should offer is not always sufficient, as it is
sometimes run in control-plane software. In the absence of ACLs, it
is possible to attack a BGP speaker by simply sending a high volume
of connection requests to it.
How we scan
We scan by sending a BGP OPEN
Message (a request to start a negotiation for a BGP session). We tag a service as open when we receive a response that matches the filter: message_type == “OPEN” and (message2_type == ” or message2_type == “KEEPALIVE”).
We do not perform any intrusive checks on a discovered service.
Dashboard
You can track accessible BGP servers on our Dashboard here.
As of July 1st, we see 115 routers that we consider “open”.
Mitigation
BGP services should not be accessible publicly, or accept BGP OPEN
requests from everyone. In the latter case, it may be possible to manipulate BGP routing tables. Access should be limited only to devices that are the expected BGP neighbors. Set up an ACL to discard all packets directed to TCP port 179 on the local device and sourced from an address not known or permitted to become a BGP neighbor.
Severity levels are described here.
For more information on our scanning efforts, check out our Internet scanning summary page.
This report has an IPv4 and IPv6 version.
Filename: scan_bgp, scan6_bgp