Bug 1476958 - Locked account provides different return code if password is correct
Locked account provides different return code if password is correct
Status: CLOSED DUPLICATE of bug 1478045
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: 389-ds-base (Show other bugs)
Unspecified Unspecified
medium Severity unspecified
: rc
: ---
Assigned To: mreynolds
Viktor Ashirov
Depends On:
Blocks: CVE-2017-7551
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Reported: 2017-07-31 20:05 EDT by wibrown@redhat.com
Modified: 2017-08-24 13:22 EDT (History)
2 users (show)

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Last Closed: 2017-08-24 13:22:26 EDT
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Description wibrown@redhat.com 2017-07-31 20:05:34 EDT
This bug is created as a clone of upstream ticket:

The directory server password lockout policy prevents binds from operating once a threshold of failed passwords has been met. During this lockout, if you bind with a successful password, a different error code is returned. This means that an attacker has no ratelimit or penalty during an account lock, and can continue to attempt passwords via bruteforce. 

Proof of concept:

ldapwhoami -H ldap://localhost -x -D 'uid=testuser,dc=example,dc=com' -w
dn: uid=testuser,dc=example,dc=com

Bind with invalid credentials a number of times to trigger the lockout:

ldapwhoami -H ldap://localhost -x -D 'uid=testuser,dc=example,dc=com' -w
ldap_bind: Invalid credentials (49)

Then bind with valid crendentials while the lockout is in effect:

ldapwhoami -H ldap://localhost -x -D 'uid=testuser,dc=example,dc=com' -w
ldap_bind: Constraint violation (19)
        additional info: Exceed password retry limit. Please try later.

Workaround: Use PBKDF2_SHA256 to delay the rate at which an attacker can attempt binds. Limit the number of threads allowed to anonymous.
Comment 3 Nathan Kinder 2017-08-24 13:22:26 EDT

*** This bug has been marked as a duplicate of bug 1478045 ***

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