for a first posting, this is a bit large: i'm really sorry about that.
future versions will be available from:
http://mailhost.cb1.com/~lkcl/cifsntdomain.txt
and a txt2html converted version:
http://mailhost.cb1.com/~lkcl/cifsntdomain.html
Luke Kenneth Casson Leighton (lkcl@switchboard.net)
Web site under construction (http://mailhost.cb1.com/~lkcl)
"Confront difficulties while they are still easy"
NT Domain Authentication
------------------------
Author: Luke Kenneth Casson Leighton (lkcl@switchboard.net)
Version: 0.004 (02oct97)
Distribution: Unlimited and encouraged.
Liability: Absolutely none accepted for use, misuse, lack of use,
misunderstandings, mistakes, or anything else that a
lawyer can think of or not think of.
Sources: Packet Traces from Netmonitor (Service Pack 1 and above)
Paul Ashton and Luke Leighton's other "NT Domain Auth" doc.
CIFS documentation - cifs6.txt
Original: http://mailhost.cb1.com/~lkcl/cifsntdomain.txt
Contents:
1) Introduction
2) Structures and notes
2.1) Notes
2.2) Structures
3) Transact Named Pipe Header/Tail
3.1) Header
3.2) Tail
4) NTLSA Transact Named Pipe
4.1) LSA Open Policy
4.2) LSA Query Info Policy
4.3) LSA Enumerate Trusted Domains
4.4) LSA Open Secret
4.5) LSA Close
4.6) LSA Lookup SIDS
4.7) LSA Lookup Names
5) NETLOGON rpc Transact Named Pipe
5.1) LSA Request Challenge
5.2) LSA Authenticate 2
5.3) LSA Server Password Set
5.4) LSA SAM Logon
5.5) LSA SAM Logoff
6) \\MAILSLOT\NET\NTLOGON
6.1) Query for PDC
6.2) SAM Logon
1) Introduction
---------------
This document contains information to provide an NT workstation with login
services, without the need for an NT server.
The packets described here can be easily derived from (and are probably
better understood using) Netmon.exe. You will need to use the version
of Netmon that matches your system, in order to correctly decode the
NETLOGON and lsarpc Transact pipes. This document is derived from NT
Service Pack 1 and its corresponding version of Netmon. It is intended
that an annotated packet trace be produced, which will likely be more
instructive than this document.
Also needed, to fully implement NT Domain Login Services, is the
document describing the cryptographic part of the NT authentication.
This document is available from comp.protocols.smb; from the ntsecurity.net
digest and from the samba digest, amongst other sources.
A c-code implementation, provided by Linus Nordberg <linus@incolumitas.se>
of this protocol is available from:
http://samba.canberra.edu.au/pub/samba/digest/currentyear/0547.html
Also used to provide debugging information is the Check Build version of
NT workstation, and enabling full debugging in NETLOGON. This is
achieved by setting the following REG_SZ registry key to 0x1ffffff:
HKLM\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters
- Incorrect direct editing of the registry can cause your machine to fail.
This document is by no means complete or authoritative.
2) Notes and Structures
-----------------------
2.1) Notes
----------
- In the SMB Transact pipes, some "Structures", described here, appear to be
4-byte aligned with the SMB header, at their start. Exactly which
"Structures" need aligning is not precisely known or documented.
- In the UDP NTLOGON Mailslots, some "Structures", described here, appear to be
2-byte aligned with the start of the mailslot, at their start.
- Domain SID is of the format S-revision-version-auth1-auth2...authN.
e.g S-1-5-123-456-789-123-456. the 5 could be a sub-revision.
- any undocumented buffer pointers must be non-zero if the string buffer it
refers to contains characters. exactly what value they should be is unknown.
0x0000 0002 seems to do the trick to indicate that the buffer exists. a
NULL buffer pointer indicates that the string buffer is of zero length.
2.2) Structures
---------------
- sizeof VOID* is 32 bits.
- sizeof char is 8 bits.
- UTIME is 32 bits, indicating time in seconds since 01jan1970. documented
in cifs6.txt (section 3.5 page, page 30).
- NTTIME is 64 bits. documented in cifs6.txt (section 3.5 page, page 30).
- DOM_SID (domain SID structure) is:
UINT32 num of sub-authorities in domain SID
UINT8 SID revision number
UINT8 num of sub-authorities in domain SID
UINT8[6] 6 bytes for domain SID
UINT16[n_subauths] domain SID sub-authorities
Note: the domain SID is documented elsewhere.
- STR (string) is:
char[] null-terminated string of ascii characters.
- UNIHDR (unicode string header) is:
UINT16 max length of unicode string
UINT16 length of unicode string
UINT32 4 - undocumented.
- UNIHDR2 (unicode string header plus buffer pointer) is:
UNIHDR unicode string header
VOID* undocumented buffer pointer
- UNISTR (unicode string) is:
UINT16[] null-terminated string of unicode characters.
- UNISTR2 (aligned unicode string) is:
UINT8[] padding to get unicode string 4-byte aligned
with the start of the SMB header.
UINT32 max length of unicode string
UINT32 0 - undocumented
UINT32 length of unicode string
UINT16[] string of uncode characters.
- DOM_SID2 (domain SID structure, SIDS stored in unicode) is:
UINT32 5 - SID type
UINT32 0 - undocumented
UNIHDR2 domain SID unicode string header
UNISTR domain SID unicode string
Note: the SID type indicates, for example, an alias; a well-known group etc.
this is documented somewhere.
- DOM_RID (domain RID structure) is:
UINT32 5 - well-known SID. 1 - user SID (see ShowACLs)
UINT32 5 - undocumented
UINT32 domain RID
UINT32 0 - domain index out of above reference domains
- LOG_INFO (server, account, client structure) is:
Note: logon server name starts with two '\' characters and is upper case.
Note: account name is the logon client name from the LSA Request Challenge,
with a $ on the end of it, in upper case.
VOID* undocumented buffer pointer
UNISTR2 logon server unicode string
UNISTR2 account name unicode string
UINT16 sec_chan - security channel type
UNISTR2 logon client machine unicode string
- CREDS (credentials + time stamp)
char[8] credentials
UTIME time stamp
- CLNT_INFO (server, account, client structure, client credentials) is:
Note: whenever this structure appears in a request, you must take a copy
of the client-calculated credentials received, because they will be
used in subsequent credential checks. the presumed intention is to
maintain an authenticated request/response trail.
LOG_INFO logon account info
CREDS client-calculated credentials + client time
- SAM_INFO (sam logon/logoff id info structure) is:
CLNT_INFO client identification/authentication info
CRED return credentials - ignored.
UINT16 logon level
UINT32 undocumented - auth_level?
switch (auth_level)
case 1:
{
UINT8[] ???? padding, for 4-byte alignment with SMB header?
UNIHDR domain name unicode header
UINT32 param control
UINT64 logon ID
UNIHDR user name unicode header
UNIHDR workgroup name unicode header
char[16] rc4 LM OWF Password
char[16] rc4 NT OWF Password
UNISTR2 domain name unicode string
UNISTR2 user name unicode string
UNISTR2 workgroup name unicode string
}
- GID (group id info) is:
UINT32 group id
UINT32 user attributes (only used by NT 3.1 and 3.51)
3) Transact Named Pipe Header/Tail
----------------------------------
3.1) Header
----------
The start of each of the NTLSA and NETLOGON named pipes begins with:
00 UINT8 5 - RPC major version
01 UINT8 0 - RPC minor version
02 UINT8 2 - RPC response packet
03 UINT8 3 - first frag + last frag
04 UINT32 0x0000 0010 - packed data representation
08 UINT16 fragment length - data size (bytes) inc header and tail.
0A UINT16 0 - authentication length
0C UINT32 call identifier. matches 12th UINT32 of incoming RPC data.
10 UINT32 allocation hint - data size (bytes) minus header and tail.
14 UINT16 0 - presentation context identifier
16 UINT8 0 - cancel count
17 UINT8 0 - reserved
18 ...... start of data (goes on for allocation_hint bytes)
3.2 Tail
--------
The end of each of the NTLSA and NETLOGON named pipes ends with:
...... end of data
UINT32 return code
4) NTLSA Transact Named Pipe
----------------------------
Defines for this pipe, identifying the query are:
- LSA Open Policy: 0x2c
- LSA Query Info Policy: 0x07
- LSA Close: 0x00
- LSA Enumerate Trusted Domains: 0x0d
- LSA Lookup SIDs: 0x0f
- LSA Lookup Names: 0x0e
- LSA Open Secret: 0x1c
4.1) LSA Open Policy
--------------------
Note: The policy handle can be anything you like.
Request:
no extra data.
Response:
char[20] policy handle
return 0 - indicates success
4.2) LSA Query Info Policy
--------------------------
Note: The info class in response must be the same as that in the request.
Request:
starting from offset 44:
UINT16 info class (also a policy handle?)
Response:
VOID* undocumented buffer pointer
UINT16 info class (same as info class in request).
switch (info class)
case 3:
case 5:
{
UINT8[] ??? padding to get 4-byte alignment with start of SMB header
UINT16 domain name string length * 2
UINT16 domain name string length * 2
VOID* undocumented domain name string buffer pointer
VOID* undocumented domain SID string buffer pointer
UNISTR domain name (unicode string)
DOM_SID domain SID
}
return 0 - indicates success
4.3) LSA Enumerate Trusted Domains
----------------------------------
Request:
no extra data
Response:
UINT32 0 - enumeration context
UINT32 0 - entries read
UINT32 0 - trust information
return 0x8000 001a - "no trusted domains" success code
4.4) LSA Open Secret
--------------------
Request:
no extra data
Response:
UINT32 0 - undocumented
UINT32 0 - undocumented
UINT32 0 - undocumented
UINT32 0 - undocumented
UINT32 0 - undocumented
return 0x0C00 0034 - "no such secret" success code
4.5) LSA Close
--------------
Request:
no extra data
Response:
UINT32 0 - undocumented
UINT32 0 - undocumented
UINT32 0 - undocumented
UINT32 0 - undocumented
UINT32 0 - undocumented
return 0 - indicates success
4.6) LSA Lookup SIDS
--------------------
Note: num_entries in response must be same as num_entries in request.
Request:
char[20] policy handle
UINT32 num_entries
VOID* undocumented domain SID buffer pointer
VOID* undocumented domain name buffer pointer
VOID*[num_entries] undocumented domain SID pointers to be looked up.
DOM_SID[num_entries] domain SIDs to be looked up.
char[16] completely undocumented 16 bytes.
Response:
VOID* undocumented buffer pointer.
UINT32 num referenced domains?
VOID* undocumented domain name buffer pointer.
UINT32 32 - max number of entries
UINT32 4 - num referenced domains?
UNIHDR2 domain name unicode string header
UNIHDR2[num_ref_doms] referenced domain unicode string headers
UNISTR domain name unicode string
DOM_SID domain SID
DOM_SID[num_ref_doms] referenced domain SIDs
UINT32 num_entries (listed above)
VOID* undocumented buffer pointer
UINT32 num_entries (listed above)
DOM_SID2[num_entries] domain SIDs (from Request, listed above).
UINT32 num_entries (listed above)
return 0 - indicates success
4.7) LSA Lookup Names
---------------------
Note: num_entries in response must be same as num_entries in request.
Request:
char[20] policy handle
UINT32 num_entries
UINT32 num_entries
VOID* undocumented domain SID buffer pointer
VOID* undocumented domain name buffer pointer
NAME[num_entries] names to be looked up.
char[] undocumented bytes - falsely translated SID structure?
Response:
VOID* undocumented buffer pointer.
UINT32 num referenced domains?
VOID* undocumented domain name buffer pointer.
UINT32 32 - max number of entries
UINT32 4 - num referenced domains?
UNIHDR2 domain name unicode string header
UNIHDR2[num_ref_doms] referenced domain unicode string headers
UNISTR domain name unicode string
DOM_SID domain SID
DOM_SID[num_ref_doms] referenced domain SIDs
UINT32 num_entries (listed above)
VOID* undocumented buffer pointer
UINT32 num_entries (listed above)
DOM_RID[num_entries] domain SIDs (from Request, listed above).
UINT32 num_entries (listed above)
return 0 - indicates success
5) NETLOGON rpc Transact Named Pipe
-----------------------------------
Defines for this pipe, identifying the query are:
- LSA Request Challenge: 0x04
- LSA Server Password Set: 0x06
- LSA SAM Logon: 0x02
- LSA SAM Logoff: 0x03
- LSA Authenticate 2: 0x0f
- LSA Logon Control: 0x0e
5.1) LSA Request Challenge
--------------------------
Note: logon server name starts with two '\' characters and is upper case.
Note: logon client is the machine, not the user.
Note: the initial LanManager password hash, against which the challenge
is issued, is the machine name itself (lower case). there will be
calls issued (LSA Server Password Set) which will change this, later.
refusing these calls allows you to always deal with the same password
(i.e the LM# of the machine name in lower case).
Request:
VOID* undocumented buffer pointer
UNISTR2 logon server unicode string
UNISTR2 logon client unicode string
char[8] client challenge
Response:
char[8] server challenge
return 0 - indicates success
5.2) LSA Authenticate 2
-----------------------
Note: in between request and response, calculate the client credentials,
and check them against the client-calculated credentials (this
process uses the previously received client credentials).
Note: neg_flags in the response is the same as that in the request.
Note: you must take a copy of the client-calculated credentials received
here, because they will be used in subsequent authentication packets.
Request:
LOG_INFO client identification info
char[8] client-calculated credentials
UINT8[] padding to 4-byte align with start of SMB header.
UINT32 neg_flags - negotiated flags (usual value is 0x0000 01ff)
Response:
char[8] server credentials.
UINT32 neg_flags - same as neg_flags in request.
return 0 - indicates success. failure value unknown.
5.3) LSA Server Password Set
----------------------------
Note: the new password is suspected to be a DES encryption using the old
password to generate the key.
Note: in between request and response, calculate the client credentials,
and check them against the client-calculated credentials (this
process uses the previously received client credentials).
Note: the server credentials are constructed from the client-calculated
credentials and the client time + 1 second.
Note: you must take a copy of the client-calculated credentials received
here, because they will be used in subsequent authentication packets.
Request:
CLNT_INFO client identification/authentication info
char[] new password - undocumented.
Response:
CREDS server credentials. server time stamp appears to be ignored.
return 0 - indicates success; 0xC000 006a indicates failure
5.4) LSA SAM Logon
------------------
Note: valid_user is True iff the username and password hash are valid for
the requested domain.
Request:
SAM_INFO sam_id structure
Response:
VOID* undocumented buffer pointer
CREDS server credentials. server time stamp appears to be ignored.
if (valid_user)
{
VOID* non-zero - undocumented buffer pointer.
NTTIME logon time
NTTIME logoff time
NTTIME kickoff time
NTTIME password last set time
NTTIME password can change time
NTTIME password must change time
UNIHDR username unicode string header
UNIHDR user's full name unicode string header
UNIHDR logon script unicode string header
UNIHDR profile path unicode string header
UNIHDR home directory unicode string header
UNIHDR home directory drive unicode string header
UINT16 logon count
UINT16 bad password count
UINT32 User ID
UINT32 Group ID
UINT32 num groups
VOID* undocumented buffer pointer to groups.
UINT32 user flags
char[16] unused user session key
UNIHDR logon server unicode string header
UNIHDR logon domain unicode string header
VOID* undocumented logon domain id pointer
char[40] unused padding bytes.
UINT32 0 - num_sids
VOID* NULL - undocumented pointer to SIDs.
UNISTR2 username unicode string
UNISTR2 user's full name unicode string
UNISTR2 logon script unicode string
UNISTR2 profile path unicode string
UNISTR2 home directory unicode string
UNISTR2 home directory drive unicode string
UINT32 num groups
GID[num_groups] group info
UNISTR2 logon server unicode string
UNISTR2 logon domain unicode string
DOM_SID[2?] undocumented - domain SIDs
DOM_SID domain SID
UINT32 1 - Authoritative response; 0 - Non-Auth?
return 0 - indicates success
}
else
{
VOID* 0x0000 0000 - undocumented buffer pointer
UINT32 1 - Authoritative response; 0 - Non-Auth?
return 0xC000 0064 - indicates failure
}
5.5) LSA SAM Logoff
--------------------
Note: presumably, the SAM_INFO structure is validated, and a (currently
undocumented) error code returned if the Logoff is invalid.
Request:
SAM_INFO sam_id structure
Response:
VOID* undocumented buffer pointer
CREDS server credentials. server time stamp appears to be ignored.
6) \\MAILSLOT\NET\NTLOGON
-------------------------
Note: mailslots will contain a response mailslot, to which the response
should be sent. the target NetBIOS name is REQUEST_NAME<20>, where
REQUEST_NAME is the name of the machine that sent the request.
6.1) Query for PDC
------------------
Note: NTversion, LMNTtoken, LM20token in response are the same as those
given in the request.
Request:
UINT16 0x0007 - Query for PDC
STR machine name
STR response mailslot
UINT8[] padding to 2-byte align with start of mailslot.
UNISTR machine name
UINT32 NTversion
UINT16 LMNTtoken
UINT16 LM20token
Response:
UINT16 0x000A - Respose to Query for PDC
STR machine name (in uppercase)
UINT8[] padding to 2-byte align with start of mailslot.
UNISTR machine name
UNISTR domain name
UINT32 NTversion (same as received in request)
UINT16 LMNTtoken (same as received in request)
UINT16 LM20token (same as received in request)
6.2) SAM Logon
--------------
Note: machine name in response is preceded by two '\' characters.
Note: NTversion, LMNTtoken, LM20token in response are the same as those
given in the request.
Note: user name in the response is presumably the same as that in the request.
Request:
UINT16 0x0012 - SAM Logon
UINT16 request count
UNISTR machine name
UNISTR user name
STR response mailslot
UINT32 alloweable account
UINT32 domain SID size
char[sid_size] domain SID, of sid_size bytes.
UINT8[] ???? padding to 4? 2? -byte align with start of mailslot.
UINT32 NTversion
UINT16 LMNTtoken
UINT16 LM20token
Response:
UINT16 0x0013 - Response to SAM Logon
UNISTR machine name
UNISTR user name - workstation trust account
UNISTR domain name
UINT32 NTversion
UINT16 LMNTtoken
UINT16 LM20token