UPEK Fingerprint Reader Software Puts Windows Passwords At Risk
colinneagle writes with this excerpt from Network World: "If your password management system is to use your 'fingerprint as your master password,' and if your laptop uses UPEK software, then you'll not be happy to know your Windows password is not secure and instead is easily crackable. In fact, 'UPEK's implementation is nothing but a big, glowing security hole compromising (and effectively destroying) the entire security model of Windows accounts.' On the Elcomsoft blog about 'advanced password cracking insight,' Olga Koksharova had bad news for people who thought they were more secure by using biometrics, a UPEK fingerprint reader, instead of relying on a password. UPEK stores Windows account passwords in the registry 'almost in plain text, barely scrambled but not encrypted.' It's not just a few that are susceptible to hacking. 'All laptops equipped with UPEK fingerprint readers and running UPEK Protector Suite are susceptible. If you ever registered your fingerprints with UPEK Protector Suite for accelerated Windows login and typed your account password there, you are at risk.'"
Using fingerprint data as an decryption key is very hard as the information is quite noisy. However, an decryption key is still needed to fetch the password (which, in turn, is needed for example to access encrypted files). Without a secure boot infrastructure a TPM doesn't help, so that leaves only the possibility of storing the key on-disk. Once the key is located, obtaining the password is trival so it doesn't really matter whether strong encryption is used.
This means that probably all fingerprint scanner software suffers from this flaw.