OCIPasswordChange API leaks information of password hash (CVE-2012-0511)

[Esteban Martinez Fayo <efayo@xxxxxxxxxxxxx>]

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AppSecInc Team SHATTER Security Advisory

OCIPasswordChange API leaks information of password hash.

Risk Level:
High

Affected versions:
Oracle Database Server version 10gR1, 10gR2 (10.2.0.4 and previous
patchsets) and 11gR1 (11.1.0.7 and previous patchsets)


Remote exploitable:
Yes (No authentication is required)

Credits:
This vulnerability was discovered and researched by Esteban Martinez
Fayo of Application Security Inc.

Details:
Oracle Database provides OCIPasswordChange API to change user passwords.
This API can be used while a user is logged on as well as before the
authentication process is completed, this is because it can be used for
accounts that have the password expired so that the user is able to
change an expired password for a new one.
It was observed that for locked accounts this API leaks information
about the correct user password hash by giving different responses,
depending on whether the decryption of the new password
(AUTH_NEW_PASSWORD field), performed by the server, is successful or
not.  This information can be used to perform an off-line brute force
attack to guess the correct password.  Internal proof-of-concept tool
demonstrated that it is possible to try millions of passwords per
second, making it possible to crack passwords that are less than 9
characters length in a few hours.
Note that to perform this attack the account must be locked.  An
attacker can lock an account by reaching the maximum failed login
attempts limit (by default 10).  The attacker will be able to log in as
the user once the account is unlocked.

Impact:
Remote unauthenticated attackers can perform off-line unlimited password
guesses on locked database accounts.

Vendor Status:
Vendor was contacted and a patch was released.

Workaround:
Implement a strong password policy.
Use some kind of external authentication (like network or directory
service based) instead of native database authentication.

Fix:
Apply Oracle Critical Patch Update April 2012 available at Oracle Support.

CVE:
CVE-2012-0511

Links:
http://www.oracle.com/technetwork/topics/security/cpuapr2012-366314.html
https://www.teamshatter.com/?p=3434

Timeline:
Vendor Notification - 12/08/2011
Vendor Response - 12/15/2011
Fix - 4/17/2012
Public Disclosure - 4/19/2012




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Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
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