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Perhaps my comment wasn't clear. I agree that its not possible for one application to access another's keychain items. However, this isn't the only attack risk,

by sjlo 14y ago

Perhaps my comment wasn't clear. I agree that its not possible for one application to access another's keychain items. However, this isn't the only attack risk, and access to keychain items in general is based on the passcode. This can be a problem if weak passcodes are used and an attacker can get access to the device. There are some relevant comments in this paper: http://sit.sit.fraunhofer.de/studies/en/sc-iphone-passwords-faq.pdf http://sit.sit.fraunhofer.de/studies/en/sc-iphone-passwords-...

brettm 14y ago
I agree that this could be a problem but in this paper in order for the attack method to work the developer of the App would need to explicitly set the keychain attribute with the flag "kSecAttrAccessibleAlways", making the keychain data available even when the device is locked, "Otherwise the credentials of the app are not affected by the attack method."
- sjlo 14y ago
  Section 2.15 deals with the conditions under which the Keychain should be considered secure: - Items are stored with a protection class that makes them only available when the device is unlocked. (see Section 2.14) - A strong passcode of 6 alphanumeric digits is enforced (reduces the risk of brute-force attacks) The second point is as relevant as the first. The paper goes on to say: according to [App10b]: ... The standard simple code of 4 numeric digits would be brute-forced in less than 9 minutes. Based on the assumption that the counter for wrong tries in the iOS can be bypassed, as it is not hardware-based. [BS11b] provides a tool for passcode bruteforce attacks. Forensic toolkits, like the one from Elcomsoft (http://www.elcomsoft.com/eift.html http://www.elcomsoft.com/eift.html), are able to recover numeric pass codes and extract data in less than an hour, even on newer devices. With a weak passcode, which most people use, the keychain does not offer much protection against dedicated attackers with device access.

by sjlo 14y ago

brettm 14y ago

I agree that this could be a problem but in this paper in order for the attack method to work the developer of the App would need to explicitly set the keychain attribute with the flag "kSecAttrAccessibleAlways", making the keychain data available even when the device is locked, "Otherwise the credentials of the app are not affected by the attack method."

sjlo 14y ago
Section 2.15 deals with the conditions under which the Keychain should be considered secure: - Items are stored with a protection class that makes them only available when the device is unlocked. (see Section 2.14) - A strong passcode of 6 alphanumeric digits is enforced (reduces the risk of brute-force attacks) The second point is as relevant as the first. The paper goes on to say: according to [App10b]: ... The standard simple code of 4 numeric digits would be brute-forced in less than 9 minutes. Based on the assumption that the counter for wrong tries in the iOS can be bypassed, as it is not hardware-based. [BS11b] provides a tool for passcode bruteforce attacks. Forensic toolkits, like the one from Elcomsoft (http://www.elcomsoft.com/eift.html http://www.elcomsoft.com/eift.html), are able to recover numeric pass codes and extract data in less than an hour, even on newer devices. With a weak passcode, which most people use, the keychain does not offer much protection against dedicated attackers with device access.