6 ms·

You mean because the data is used in a readable form at some point or another, a compromise would have resulted either way? Can't say I'm sold, my friend.

by sova 9y ago

tptacek 9y ago
Yes: because the point of encryption is to protect you from a compromise in your server (that's what happened at Equifax), but for the server to be able to use the data, it has to have have some means of getting plaintext access to it. Once you've lost your server to an attacker, you've lost control of that mechanism as well. This is a problem even with HSM designs; in real-world systems, HSMs usually just present an oracle interface to data. The hope is that with sufficient monitoring, you can use the oracle to buy time for defenders to detect a compromise before all your data is exfiltrated. I think most penetration testers have the experience of owning up a server and going on the brief treasure hunt for the static key stored somewhere on the filesystem.
- dredmorbius 9y ago
  What is "HSM" in this context? Among probable hits, "hierarchical storage management" and "hardware security module".
  - tptacek 9y ago
    Hardware security module.
  - thristian 9y ago
    Hardware Security Module, a device that stores a private key in a way that cannot be easily extracted. When your application needs to decrypt something, it sends a request over the network to the HSM, which decrypts it and returns the plaintext.
- nitwit005 9y ago
  The point of encryption is often just to prevent people from walking off with hard disks and getting at the data. Remember that companies often have backups managed by 3rd parties.
- sova 9y ago
  Most people use encryption in the following way for passwords: user provides input, input is hashed, hash is stored, future attempts to log in are hashed and compared. This is very secure. Server compromised? No problem, all they get is a bunch of hashed stuff. Hashing is the main business of a bureau of any sort of public data. That is the business in 2017. If personal data were kept as fuzzy hashes that required partial knowledge to decrypt, systems would be more robust and information would be better protected. It is not a new idea, just an oft overlooked one.
itissid 9y ago
Once you have remote code execution with privilege escalation on box Z, no amount of encryption can save at least box Z

You mean because the data is used in a readable form at some point or another, a compromise would have resulted either way? Can't say I'm sold, my friend.

by sova 9y ago

You mean because the data is used in a readable form at some point or another, a compromise would have resulted either way? Can't say I'm sold, my friend.

tptacek 9y ago

Yes: because the point of encryption is to protect you from a compromise in your server (that's what happened at Equifax), but for the server to be able to use the data, it has to have have some means of getting plaintext access to it. Once you've lost your server to an attacker, you've lost control of that mechanism as well. This is a problem even with HSM designs; in real-world systems, HSMs usually just present an oracle interface to data. The hope is that with sufficient monitoring, you can use the oracle to buy time for defenders to detect a compromise before all your data is exfiltrated. I think most penetration testers have the experience of owning up a server and going on the brief treasure hunt for the static key stored somewhere on the filesystem.

dredmorbius 9y ago
What is "HSM" in this context? Among probable hits, "hierarchical storage management" and "hardware security module".
- tptacek 9y ago
  Hardware security module.
- thristian 9y ago
  Hardware Security Module, a device that stores a private key in a way that cannot be easily extracted. When your application needs to decrypt something, it sends a request over the network to the HSM, which decrypts it and returns the plaintext.
nitwit005 9y ago
The point of encryption is often just to prevent people from walking off with hard disks and getting at the data. Remember that companies often have backups managed by 3rd parties.
sova 9y ago
Most people use encryption in the following way for passwords: user provides input, input is hashed, hash is stored, future attempts to log in are hashed and compared. This is very secure. Server compromised? No problem, all they get is a bunch of hashed stuff. Hashing is the main business of a bureau of any sort of public data. That is the business in 2017. If personal data were kept as fuzzy hashes that required partial knowledge to decrypt, systems would be more robust and information would be better protected. It is not a new idea, just an oft overlooked one.

itissid 9y ago

Once you have remote code execution with privilege escalation on box Z, no amount of encryption can save at least box Z