CAS-002 · Question #768
A security consultant is conducting a network assessment and wishes to discover any legacy backup Internet connections the network may have. Where would the consultant find this information and why…
The correct answer is A. This information can be found in global routing tables, and is valuable because backup. Global routing tables (BGP) reveal all publicly announced IP prefixes for an autonomous system, including backup or secondary ISP connections that may have been forgotten but are still active.
Question
A security consultant is conducting a network assessment and wishes to discover any legacy backup Internet connections the network may have. Where would the consultant find this information and why would it be valuable?
Options
- AThis information can be found in global routing tables, and is valuable because backup
- BThis information can be found by calling the regional Internet registry, and is valuable because
- CThis information can be found by accessing telecom billing records, and is valuable because
- DThis information can be found by querying the network's DNS servers, and is valuable because
How the community answered
(57 responses)- A82% (47)
- B4% (2)
- C5% (3)
- D9% (5)
Why each option
Global routing tables (BGP) reveal all publicly announced IP prefixes for an autonomous system, including backup or secondary ISP connections that may have been forgotten but are still active.
BGP global routing tables aggregate every publicly announced IP prefix and the autonomous system paths used to reach them. A legacy backup Internet connection would still be advertised via BGP if it remains active, making it visible in tools like RouteViews or RIPE NCC's RIS. This is valuable to a penetration tester because forgotten backup links are often less monitored and can serve as an unguarded entry point into the network.
Regional Internet Registries (RIRs) like ARIN hold IP allocation and registration records but do not expose active routing paths or reveal which connections are currently in use as backup links.
Telecom billing records are private business documents that are not accessible during a standard network assessment and require legal process to obtain, making them an impractical reconnaissance source.
DNS servers store name-to-IP mappings and mail/service records but contain no routing topology information that would reveal backup ISP connections or alternate network paths.
Concept tested: BGP routing table reconnaissance for network assessment
Source: https://csrc.nist.gov/publications/detail/sp/800-115/final
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