import ctypes
class CREDENTIALS(ctypes.Structure):
    _fields_ = [
        ("Flags", ctypes.c_int),
        ("Type", ctypes.c_int),
        ("TargetName", ctypes.c_wchar_p),
        ("Comment", ctypes.c_wchar_p),
        ("CredentialBlobSize", ctypes.c_int),
        ("CredentialBlob", ctypes.c_wchar_p),
        ("AttributeCount", ctypes.c_int),
        ("Attributes", ctypes.c_wchar_p),
        ("TargetAlias", ctypes.c_wchar_p),
        ("UserName", ctypes.c_wchar_p)
]
advapi32 = ctypes.oledll.LoadLibrary('Advapi32.dll')
advapi32.CredReadW.restype = ctypes.c_bool
advapi32.CredReadW.argtypes = [ctypes.c_wchar_p, ctypes.c_int, ctypes.c_int, ctypes.POINTER(CREDENTIALS)]
target = "login.example.com"
pcred = ctypes.pointer(CREDENTIALS())
ok = advapi32.CredReadW(target,1,0,pcred)
cred = pcred.contents
print ok, pcred, cred.UserName, cred.CredentialBlob