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Ok, I've got a stupid question that's been in the back of my head for years, so I'm just gonna ask. In a BGP hijacking attack, can traffic be decrypted by some

Ok, I've got a stupid question that's been in the back of my head for years, so I'm just gonna ask. In a BGP hijacking attack, can traffic be decrypted by somehow linking it to a new (root) CA the attacker owns?

arlort 3y ago
Decrypting implies a message sent to the real owner of the domain (using their public key) being intercepted and decoded. If that's the case then no, once you have encrypted a message with a public key (or more realistically exchanged a symmetric key using the public key) that message is as safe as it can be With BGP hijacking you could intercept the traffic from the real website, but you still need a valid certificate which is signed (indirectly) by a trusted CA, meaning the attacker would need to add their root CA to the list on the user device
- pieter_mj 3y ago
  thanks, existing traffic is symmetrically encrypted already and can no longer be decrypted by the intercepting party. But future traffic could be. For instance, I found this : https://www.princeton.edu/~pmittal/publications/bgp-tls-usenix18.pdf https://www.princeton.edu/~pmittal/publications/bgp-tls-usen...
  - arlort 3y ago
    Ok, yeah, I hadn't thought about the certificate issue phase, though that's a different concern than what you talked about initially. The victim in the paper you mention aren't users but rather the CAs themselves (though the certificates issued can then be used against users)
blueflow 3y ago
How would the attacker get their CA cert into the trusted certificate store of the clients?
- pieter_mj 3y ago
  By having an already trusted CA cert on the client. But that would involve a really elaborate attack by an APT (having for instance a stolen CA that's still valid).
ilyt 3y ago
Nope, but you could intercept the traffic to their IP then use Letsencrypt to generate a bunch of new certs on their domains, as only thin needed to validate non-wildcard certs are few http requests to a given IP that domain points to

arlort 3y ago

Decrypting implies a message sent to the real owner of the domain (using their public key) being intercepted and decoded. If that's the case then no, once you have encrypted a message with a public key (or more realistically exchanged a symmetric key using the public key) that message is as safe as it can be With BGP hijacking you could intercept the traffic from the real website, but you still need a valid certificate which is signed (indirectly) by a trusted CA, meaning the attacker would need to add their root CA to the list on the user device

pieter_mj 3y ago
thanks, existing traffic is symmetrically encrypted already and can no longer be decrypted by the intercepting party. But future traffic could be. For instance, I found this : https://www.princeton.edu/~pmittal/publications/bgp-tls-usenix18.pdf https://www.princeton.edu/~pmittal/publications/bgp-tls-usen...
- arlort 3y ago
  Ok, yeah, I hadn't thought about the certificate issue phase, though that's a different concern than what you talked about initially. The victim in the paper you mention aren't users but rather the CAs themselves (though the certificates issued can then be used against users)

blueflow 3y ago

How would the attacker get their CA cert into the trusted certificate store of the clients?

pieter_mj 3y ago
By having an already trusted CA cert on the client. But that would involve a really elaborate attack by an APT (having for instance a stolen CA that's still valid).

ilyt 3y ago

Nope, but you could intercept the traffic to their IP then use Letsencrypt to generate a bunch of new certs on their domains, as only thin needed to validate non-wildcard certs are few http requests to a given IP that domain points to