KBAC Threat Model

Server-Side Attacks

Operation	Threat	Specific Attack	Attack Effort	Damages	KBAC Effective?	Protections in Place	Mitigations	Advice
User logs in using username/password	Network Compromised	Traffic Intercept via MITM	Medium	None	Yes.	HTTPS for transport, username and password can be used to retreive credentials but not decrypt credentials.
User logs in using username/password	Network Compromised	Traffic Intercept via MITM w/Replay Attack	High	None	Yes.	Randomly salted username/password prevents replay attacks.
Login server is hacked.	Server Compromised	"owned" server. (many)	High	None	Yes.	Login data at rest is encrypted w/keys not on server.
User downloads data from server.	Network Compromised	Traffic Intercept via MITM. Data is read.	Medium	None	Yes.	HTTPS for transport, sensitive data is in a (further) encrypted form.	AES keys randomized for each request. RSA-2048 is strong (as of 2016).	Subject to NSA-style long term storage attack.
User downloads data from server.	Network Compromised	Traffic Intercept via MITM. Request is replayed for additional information.	Medium	None	Yes.	Requests are signed, preventing request being used for any information other than the initially requested information.
User downloads data from server.	Network Compromised	Traffic Intercept via MITM. Data is manipulated.	Medium	None	Yes.	Requests are signed, preventing request being used for any information other than the initially requested information. Response data is also signed.
User downloads data from server.	Network Compromised	Traffic Intercept via MITM. Data is omitted or redirected.	Medium	Data is not stored.	Yes.	Data is signed and sensitive data is encrypted.
User downloads data from server.	Server Compromised	Malicious Server	High	Data may be unavailable.	Yes.	Data is signed and sensitive data is encrypted. User IP/fingerprints can be acquired for correlation attacks.		Subject to NSA-style long term storage attack.
User uploads data to server.	Network Compromised	Traffic Intercept via MITM. Data is read.	Medium	None	Yes.	HTTPS for transport, sensitive data is in a (further) encrypted form.	AES keys randomized for each request. RSA-2048 is strong (as of 2016).	Subject to NSA-style long term storage attack.
User uploads data to server.	Network Compromised	Traffic Intercept via MITM. Data is read and HTTPS is skimmed or a certificate attack works.	High	None	Yes.	Sensitive data is in an encrypted form.	AES keys randomized for each request. RSA-2048 is strong (as of 2016).	Subject to NSA-style long term storage attack.
User uploads data to server.	Network Compromised	Traffic Intercept via MITM. Request is replayed to overwrite changes.	High	None	Yes.	Request signature is timestamped, limiting the viability of this attack to some number of seconds after the initial capture.
User uploads data to server.	Network Compromised	Traffic Intercept via MITM. Data is manipulated.	High	None	Yes.	Request signature is timestamped, limiting the viability of this attack to some number of seconds after the initial capture.
User uploads data to server.	Network Compromised	Traffic Intercept via MITM. Data is omitted or redirected.	Medium	Data is not stored.	Yes.
User deletes data.	Network Compromised	Traffic Intercept via MITM. Data is read.	Medium	None	Yes.	HTTPS for transport, sensitive data is in a (further) encrypted form.	AES keys randomized for each request. RSA-2048 is strong (as of 2016).
User deletes data.	Network Compromised	Traffic Intercept via MITM. Request is replayed to delete additional material.	High	None	Yes.	Request signature is timestamped, limiting the viability of this attack to some number of seconds after the initial capture. Request signature also denotes the material to be deleted.
User deletes data.	Network Compromised	Traffic Intercept via MITM. Data is manipulated.	High	None	Yes.	Request signature is timestamped, limiting the viability of this attack to some number of seconds after the initial capture.
User deletes data.	Network Compromised	Traffic Intercept via MITM. Data is omitted or redirected.	Medium	Can be aborted, retaining data.	Yes.	Data is signed and sensitive data is encrypted.
User deletes data.	Server Compromised	Malicious Server	High	Can be aborted, retaining data.	Yes.	Data is signed and sensitive data is encrypted.

Client-Side Attacks

Operation	Threat	Specific Attack	Attack Effort	Damages	KBAC Effective?	Protections	Mitigations	Advice
User logs in using username/password	Client Compromised	Malicious Browser / Plugin	Low	One Person Compromised, cannot use Private Keys any longer. Public key should be blacklisted.	No.		We encourage servers to require HTTP/S which prevents some damages.
User logs in using username/password	Client Compromised	Worm / Virus / Keylogger	Low	One Person Compromised, cannot use Private Keys any longer. Public key should be blacklisted.	No.		Automated login prevents keylogger use.
User logs in using username/password	Website Compromised	Malicious Javascript	High	Every User after server compromised is compromised WRT this system. Usernames and passwords may be sniffed if re-entered. Private Keys may be compromised. Public keys should be blacklisted.	No.		Automated login uses post-hashed credentials, preventing username/password from being reused in other systems.	Client code should be served from a signed third party (Android application, other application)
User downloads data from server.	Client Compromised	Data altered before viewing on browser. (credentials added, removed, targeted attack)	High	Viewed data for compromised client.	No.			Client code should work in an isolated container, however, this theoretically can still be pierced.
User downloads data from server.	Website Compromised	Data altered before viewing on browser via malicious Javascript.	High	Viewed data for any clients who downloads the compromised site.	No.			Client code should be served from a signed third party (Android application, other application)
User uploads data to server.	Client Compromised	Malicious Browser	High	Data can be altered before upload.	No.
User uploads data to server.	Website Compromised	Malicious Javascript	High	Data can be altered via javascript before upload.	No.
User deletes data.	Client Compromised	Malicious Browser	High	Can be aborted, retaining data.	Yes.	Data is signed and sensitive data is encrypted.
User deletes data.	Website Compromised	Malicious Javascript	High	Can be aborted, retaining data.	Yes.