Chapter 2. NT Domain RPC's

Luke Leighton

Duncan Stansfield

01 November 97(version 0.0.24)

Table of Contents

Introduction
Sources
Credits
Notes and Structures
Notes
Enumerations
Structures
MSRPC over Transact Named Pipe
MSRPC Pipes
Header
Tail
RPC Bind / Bind Ack
NTLSA Transact Named Pipe
LSA Open Policy
LSA Query Info Policy
LSA Enumerate Trusted Domains
LSA Open Secret
LSA Close
LSA Lookup SIDS
LSA Lookup Names
NETLOGON rpc Transact Named Pipe
LSA Request Challenge
LSA Authenticate 2
LSA Server Password Set
LSA SAM Logon
LSA SAM Logoff
\\MAILSLOT\NET\NTLOGON
Query for PDC
SAM Logon
SRVSVC Transact Named Pipe
Net Share Enum
Net Server Get Info
Cryptographic side of NT Domain Authentication
Definitions
Protocol
Comments
SIDs and RIDs
Well-known SIDs
Well-known RIDS

Introduction

This document contains information to provide an NT workstation with login services, without the need for an NT server. It is the sgml version of http://mailhost.cb1.com/~lkcl/cifsntdomain.txt, controlled by Luke.

It should be possible to select a domain instead of a workgroup (in the NT workstation's TCP/IP settings) and after the obligatory reboot, type in a username, password, select a domain and successfully log in. I would appreciate any feedback on your experiences with this process, and any comments, corrections and additions to this document.

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, lsarpc and srvsvc 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 copy is available from:

http://ntbugtraq.rc.on.ca/SCRIPTS/WA.EXE?A2=ind9708;L=ntbugtraq;O=A;P=2935

http://mailhost.cb1.com/~lkcl/crypt.html

A c-code implementation, provided by Linus Nordberg of this protocol is available from:

https://www.samba.org/cgi-bin/mfs/01/digest/1997/97aug/0391.html

http://mailhost.cb1.com/~lkcl/crypt.txt

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. Then again, so can incorrect implementation of this protocol. See "Liability:" above.

Bear in mind that each packet over-the-wire will have its origin in an API call. Therefore, there are likely to be structures, enumerations and defines that are usefully documented elsewhere.

This document is by no means complete or authoritative. Missing sections include, but are not limited to:

  1. Mappings of RIDs to usernames (and vice-versa).

  2. What a User ID is and what a Group ID is.

  3. The exact meaning/definition of various magic constants or enumerations.

  4. The reply error code and use of that error code when a workstation becomes a member of a domain (to be described later). Failure to return this error code will make the workstation report that it is already a member of the domain.

  5. the cryptographic side of the NetrServerPasswordSet command, which would allow the workstation to change its password. This password is used to generate the long-term session key. [It is possible to reject this command, and keep the default workstation password].

Sources

cket Traces from Netmonitor (Service Pack 1 and above)
ul Ashton and Luke Leighton's other "NT Domain" doc.
FS documentation - cifs6.txt
FS documentation - cifsrap2.txt

Credits

Paul Ashton: loads of work with Net Monitor; understanding the NT authentication system; reference implementation of the NT domain support on which this document is originally based.
Duncan Stansfield: low-level analysis of MSRPC Pipes.
Linus Nordberg: producing c-code from Paul's crypto spec.
Windows Sourcer development team

Notes and Structures

Notes

  1. 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.

  2. In the UDP NTLOGON Mailslots, some "Structures", described here, appear to be 2-byte aligned with the start of the mailslot, at their start.

  3. 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.

  4. 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. If the buffer pointer is NULL, then it is suspected that the structure it refers to is NOT put into (or taken out of) the SMB data stream. This is empirically derived from, for example, the LSA SAM Logon response packet, where if the buffer pointer is NULL, the user information is not inserted into the data stream. Exactly what happens with an array of buffer pointers is not known, although an educated guess can be made.

  5. an array of structures (a container) appears to have a count and a pointer. if the count is zero, the pointer is also zero. no further data is put into or taken out of the SMB data stream. if the count is non-zero, then the pointer is also non-zero. immediately following the pointer is the count again, followed by an array of container sub-structures. the count appears a third time after the last sub-structure.

Enumerations

MSRPC Header type

command number in the msrpc packet header

MSRPC_Request:

0x00

MSRPC_Response:

0x02

MSRPC_Bind:

0x0B

MSRPC_BindAck:

0x0C

MSRPC Packet info

The meaning of these flags is undocumented

FirstFrag:

0x01

LastFrag:

0x02

NotaFrag:

0x04

RecRespond:

0x08

NoMultiplex:

0x10

NotForIdemp:

0x20

NotforBcast:

0x40

NoUuid:

0x80

Structures

VOID *

sizeof VOID* is 32 bits.

char

sizeof char is 8 bits.

UTIME

UTIME is 32 bits, indicating time in seconds since 01jan1970. documented in cifs6.txt (section 3.5 page, page 30).

NTTIME

NTTIME is 64 bits. documented in cifs6.txt (section 3.5 page, page 30).

DOM_SID (domain SID structure)

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 - Identifier Authority.

UINT16[n_subauths]

domain SID sub-authorities

Note: the domain SID is documented elsewhere.

STR (string)

STR (string) is a char[] : a null-terminated string of ascii characters.

UNIHDR (unicode string header)

UINT16

length of unicode string

UINT16

max length of unicode string

UINT32

4 - undocumented.

UNIHDR2 (unicode string header plus buffer pointer)

UNIHDR

unicode string header

VOID*

undocumented buffer pointer

UNISTR (unicode string)

UINT16[]

null-terminated string of unicode characters.

NAME (length-indicated unicode string)

UINT32

length of unicode string

UINT16[]

null-terminated string of unicode characters.

UNISTR2 (aligned unicode string)

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

OBJ_ATTR (object attributes)

UINT32

0x18 - length (in bytes) including the length field.

VOID*

0 - root directory (pointer)

VOID*

0 - object name (pointer)

UINT32

0 - attributes (undocumented)

VOID*

0 - security descriptor (pointer)

UINT32

0 - security quality of service

POL_HND (LSA policy handle)

char[20]

policy handle

DOM_SID2 (domain SID structure, SIDS stored in unicode)

UINT32

5 - SID type

UINT32

0 - undocumented

UNIHDR2

domain SID unicode string header

UNISTR

domain SID unicode string

Note: there is a conflict between the unicode string header and the unicode string itself as to which to use to indicate string length. this will need to be resolved.

Note: the SID type indicates, for example, an alias; a well-known group etc. this is documented somewhere.

DOM_RID (domain RID structure)

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)

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

CLNT_SRV (server, client names structure)

Note: logon server name starts with two '\' characters and is upper case.

VOID*

undocumented buffer pointer

UNISTR2

logon server unicode string

VOID*

undocumented buffer pointer

UNISTR2

logon client machine unicode string

CREDS (credentials + time stamp)

char[8]

credentials

UTIME

time stamp

CLNT_INFO2 (server, client structure, client credentials)

Note: whenever this structure appears in a request, you must take a copy of the client-calculated credentials received, because they will beused in subsequent credential checks. the presumed intention is to maintain an authenticated request/response trail.

CLNT_SRV

client and server names

UINT8[]

???? padding, for 4-byte alignment with SMB header.

VOID*

pointer to client credentials.

CREDS

client-calculated credentials + client time

CLNT_INFO (server, account, client structure, client credentials)

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

ID_INFO_1 (id info structure, auth level 1)

VOID*

ptr_id_info_1

UNIHDR

domain name unicode header

UINT32

param control

UINT64

logon ID

UNIHDR

user name unicode header

UNIHDR

workgroup name unicode header

char[16]

arc4 LM OWF Password

char[16]

arc4 NT OWF Password

UNISTR2

domain name unicode string

UNISTR2

user name unicode string

UNISTR2

workstation name unicode string

SAM_INFO (sam logon/logoff id info structure)

Note: presumably, the return credentials is supposedly for the server to verify that the credential chain hasn't been compromised.

CLNT_INFO2

client identification/authentication info

VOID*

pointer to return credentials.

CRED

return credentials - ignored.

UINT16

logon level

UINT16

switch value

        switch (switch_value)
        case 1:
        {
            ID_INFO_1     id_info_1;
        }

GID (group id info)

UINT32

group id

UINT32

user attributes (only used by NT 3.1 and 3.51)

DOM_REF (domain reference info)

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-1]

referenced domain unicode string headers

UNISTR

domain name unicode string

DOM_SID[num_ref_doms]

referenced domain SIDs

DOM_INFO (domain info, levels 3 and 5 are the same))

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

UNISTR2

domain name (unicode string)

DOM_SID

domain SID

USER_INFO (user logon info)

Note: it would be nice to know what the 16 byte user session key is for.

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]

user session key

UNIHDR

logon server unicode string header

UNIHDR

logon domain unicode string header

VOID*

undocumented logon domain id pointer

char[40]

40 undocumented padding bytes. future expansion?

UINT32

0 - num_other_sids?

VOID*

NULL - undocumented pointer to other domain 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

domain SID

DOM_SID[num_sids]

other domain SIDs?

SH_INFO_1_PTR (pointers to level 1 share info strings)

Note: see cifsrap2.txt section5, page 10.

0 for shi1_type indicates a Disk.
1 for shi1_type indicates a Print Queue.
2 for shi1_type indicates a Device.
3 for shi1_type indicates an IPC pipe.
0x8000 0000 (top bit set in shi1_type) indicates a hidden share.
VOID*

shi1_netname - pointer to net name

UINT32

shi1_type - type of share. 0 - undocumented.

VOID*

shi1_remark - pointer to comment.

SH_INFO_1_STR (level 1 share info strings)

UNISTR2

shi1_netname - unicode string of net name

UNISTR2

shi1_remark - unicode string of comment.

SHARE_INFO_1_CTR

share container with 0 entries:

UINT32

0 - EntriesRead

UINT32

0 - Buffer

share container with > 0 entries:

UINT32

EntriesRead

UINT32

non-zero - Buffer

UINT32

EntriesRead

SH_INFO_1_PTR[EntriesRead]

share entry pointers

SH_INFO_1_STR[EntriesRead]

share entry strings

UINT8[]

padding to get unicode string 4-byte aligned with start of the SMB header.

UINT32

EntriesRead

UINT32

0 - padding

SERVER_INFO_101

Note: see cifs6.txt section 6.4 - the fields described therein will be of assistance here. for example, the type listed below is the same as fServerType, which is described in 6.4.1.

SV_TYPE_WORKSTATION

0x00000001 All workstations

SV_TYPE_SERVER

0x00000002 All servers

SV_TYPE_SQLSERVER

0x00000004 Any server running with SQL server

SV_TYPE_DOMAIN_CTRL

0x00000008 Primary domain controller

SV_TYPE_DOMAIN_BAKCTRL

0x00000010 Backup domain controller

SV_TYPE_TIME_SOURCE

0x00000020 Server running the timesource service

SV_TYPE_AFP

0x00000040 Apple File Protocol servers

SV_TYPE_NOVELL

0x00000080 Novell servers

SV_TYPE_DOMAIN_MEMBER

0x00000100 Domain Member

SV_TYPE_PRINTQ_SERVER

0x00000200 Server sharing print queue

SV_TYPE_DIALIN_SERVER

0x00000400 Server running dialin service.

SV_TYPE_XENIX_SERVER

0x00000800 Xenix server

SV_TYPE_NT

0x00001000 NT server

SV_TYPE_WFW

0x00002000 Server running Windows for

SV_TYPE_SERVER_NT

0x00008000 Windows NT non DC server

SV_TYPE_POTENTIAL_BROWSER

0x00010000 Server that can run the browser service

SV_TYPE_BACKUP_BROWSER

0x00020000 Backup browser server

SV_TYPE_MASTER_BROWSER

0x00040000 Master browser server

SV_TYPE_DOMAIN_MASTER

0x00080000 Domain Master Browser server

SV_TYPE_LOCAL_LIST_ONLY

0x40000000 Enumerate only entries marked "local"

SV_TYPE_DOMAIN_ENUM

0x80000000 Enumerate Domains. The pszServer and pszDomain parameters must be NULL.

UINT32

500 - platform_id

VOID*

pointer to name

UINT32

5 - major version

UINT32

4 - minor version

UINT32

type (SV_TYPE_... bit field)

VOID*

pointer to comment

UNISTR2

sv101_name - unicode string of server name

UNISTR2

sv_101_comment - unicode string of server comment.

UINT8[]

padding to get unicode string 4-byte aligned with start of the SMB header.

MSRPC over Transact Named Pipe

For details on the SMB Transact Named Pipe, see cifs6.txt

MSRPC Pipes

The MSRPC is conducted over an SMB Transact Pipe with a name of \PIPE\. You must first obtain a 16 bit file handle, by sending a SMBopenX with the pipe name \PIPE\srvsvc for example. You can then perform an SMB Trans, and must carry out an SMBclose on the file handle once you are finished.

Trans Requests must be sent with two setup UINT16s, no UINT16 params (none known about), and UINT8 data parameters sufficient to contain the MSRPC header, and MSRPC data. The first UINT16 setup parameter must be either 0x0026 to indicate an RPC, or 0x0001 to indicate Set Named Pipe Handle state. The second UINT16 parameter must be the file handle for the pipe, obtained above.

The Data section for an API Command of 0x0026 (RPC pipe) in the Trans Request is the RPC Header, followed by the RPC Data. The Data section for an API Command of 0x0001 (Set Named Pipe Handle state) is two bytes. The only value seen for these two bytes is 0x00 0x43.

MSRPC Responses are sent as response data inside standard SMB Trans responses, with the MSRPC Header, MSRPC Data and MSRPC tail.

It is suspected that the Trans Requests will need to be at least 2-byte aligned (probably 4-byte). This is standard practice for SMBs. It is also independent of the observed 4-byte alignments with the start of the MSRPC header, including the 4-byte alignment between the MSRPC header and the MSRPC data.

First, an SMBtconX connection is made to the IPC$ share. The connection must be made using encrypted passwords, not clear-text. Then, an SMBopenX is made on the pipe. Then, a Set Named Pipe Handle State must be sent, after which the pipe is ready to accept API commands. Lastly, and SMBclose is sent.

To be resolved:

lkcl/01nov97 there appear to be two additional bytes after the null-terminated \PIPE\ name for the RPC pipe. Values seen so far are listed below:

        initial SMBopenX request:         RPC API command 0x26 params:
        "\\PIPE\\lsarpc"                  0x65 0x63; 0x72 0x70; 0x44 0x65;
        "\\PIPE\\srvsvc"                  0x73 0x76; 0x4E 0x00; 0x5C 0x43;

Header

[section to be rewritten, following receipt of work by Duncan Stansfield]

Interesting note: if you set packed data representation to 0x0100 0000 then all 4-byte and 2-byte word ordering is turned around!

The start of each of the NTLSA and NETLOGON named pipes begins with:

offset: 00
Variable type: UINT8
Variable data: 5 - RPC major version
offset: 01
Variable type: UINT8
Variable data: 0 - RPC minor version
offset: 02
Variable type: UINT8
Variable data: 2 - RPC response packet
offset: 03
Variable type: UINT8
Variable data: 3 - (FirstFrag bit-wise or with LastFrag)
offset: 04
Variable type: UINT32
Variable data: 0x1000 0000 - packed data representation
offset: 08
Variable type: UINT16
Variable data: fragment length - data size (bytes) inc header and tail.
offset: 0A
Variable type: UINT16
Variable data: 0 - authentication length
offset: 0C
Variable type: UINT32
Variable data: call identifier. matches 12th UINT32 of incoming RPC data.
offset: 10
Variable type: UINT32
Variable data: allocation hint - data size (bytes) minus header and tail.
offset: 14
Variable type: UINT16
Variable data: 0 - presentation context identifier
offset: 16
Variable type: UINT8
Variable data: 0 - cancel count
offset: 17
Variable type: UINT8
Variable data: in replies: 0 - reserved; in requests: opnum - see #defines.
offset: 18
Variable type: ......
Variable data: start of data (goes on for allocation_hint bytes)

RPC_Packet for request, response, bind and bind acknowledgement

UINT8 versionmaj

reply same as request (0x05)

UINT8 versionmin

reply same as request (0x00)

UINT8 type

one of the MSRPC_Type enums

UINT8 flags

reply same as request (0x00 for Bind, 0x03 for Request)

UINT32 representation

reply same as request (0x00000010)

UINT16 fraglength

the length of the data section of the SMB trans packet

UINT16 authlength

UINT32 callid

call identifier. (e.g. 0x00149594)

* stub USE TvPacket

the remainder of the packet depending on the "type"

Interface identification

the interfaces are numbered. as yet I haven't seen more than one interface used on the same pipe name srvsvc

abstract (0x4B324FC8, 0x01D31670, 0x475A7812, 0x88E16EBF, 0x00000003)
transfer (0x8A885D04, 0x11C91CEB, 0x0008E89F, 0x6048102B, 0x00000002)

RPC_Iface RW

UINT8 byte[16]

16 bytes of number

UINT32 version

the interface number

RPC_ReqBind RW

the remainder of the packet after the header if "type" was Bind in the response header, "type" should be BindAck

UINT16 maxtsize

maximum transmission fragment size (0x1630)

UINT16 maxrsize

max receive fragment size (0x1630)

UINT32 assocgid

associated group id (0x0)

UINT32 numelements

the number of elements (0x1)

UINT16 contextid

presentation context identifier (0x0)

UINT8 numsyntaxes

the number of syntaxes (has always been 1?)(0x1)

UINT8[]

4-byte alignment padding, against SMB header

* abstractint USE RPC_Iface

num and vers. of interface client is using

* transferint USE RPC_Iface

num and vers. of interface to use for replies

RPC_Address RW

UINT16 length

length of the string including null terminator

* port USE string

the string above in single byte, null terminated form

RPC_ResBind RW

the response to place after the header in the reply packet

UINT16 maxtsize

same as request

UINT16 maxrsize

same as request

UINT32 assocgid

zero

* secondaddr USE RPC_Address

the address string, as described earlier

UINT8[]

4-byte alignment padding, against SMB header

UINT8 numresults

the number of results (0x01)

UINT8[]

4-byte alignment padding, against SMB header

UINT16 result

result (0x00 = accept)

UINT16 reason

reason (0x00 = no reason specified)

* transfersyntax USE RPC_Iface

the transfer syntax from the request

RPC_ReqNorm RW

the remainder of the packet after the header for every other other request

UINT32 allochint

the size of the stub data in bytes

UINT16 prescontext

presentation context identifier (0x0)

UINT16 opnum

operation number (0x15)

* stub USE TvPacket

a packet dependent on the pipe name (probably the interface) and the op number)

RPC_ResNorm RW

UINT32 allochint

# size of the stub data in bytes

UINT16 prescontext

# presentation context identifier (same as request)

UINT8 cancelcount

# cancel count? (0x0)

UINT8 reserved

# 0 - one byte padding

* stub USE TvPacket

# the remainder of the reply

Tail

The end of each of the NTLSA and NETLOGON named pipes ends with:

......

end of data

UINT32

return code

RPC Bind / Bind Ack

RPC Binds are the process of associating an RPC pipe (e.g \PIPE\lsarpc) with a "transfer syntax" (see RPC_Iface structure). The purpose for doing this is unknown.

Note: The RPC_ResBind SMB Transact request is sent with two uint16 setup parameters. The first is 0x0026; the second is the file handle returned by the SMBopenX Transact response.

Note: The RPC_ResBind members maxtsize, maxrsize and assocgid are the same in the response as the same members in the RPC_ReqBind. The RPC_ResBind member transfersyntax is the same in the response as the

Note: The RPC_ResBind response member secondaddr contains the name of what is presumed to be the service behind the RPC pipe. The mapping identified so far is:

initial SMBopenX request:

RPC_ResBind response:

"\\PIPE\\srvsvc"

"\\PIPE\\ntsvcs"

"\\PIPE\\samr"

"\\PIPE\\lsass"

"\\PIPE\\lsarpc"

"\\PIPE\\lsass"

"\\PIPE\\wkssvc"

"\\PIPE\\wksvcs"

"\\PIPE\\NETLOGON"

"\\PIPE\\NETLOGON"

Note: The RPC_Packet fraglength member in both the Bind Request and Bind Acknowledgment must contain the length of the entire RPC data, including the RPC_Packet header.

Request:

RPC_Packet
RPC_ReqBind

Response:

RPC_Packet
RPC_ResBind

NTLSA Transact Named Pipe

The sequence of actions taken on this pipe are:

Establish a connection to the IPC$ share (SMBtconX). use encrypted passwords.
Open an RPC Pipe with the name "\\PIPE\\lsarpc". Store the file handle.
Using the file handle, send a Set Named Pipe Handle state to 0x4300.
Send an LSA Open Policy request. Store the Policy Handle.
Using the Policy Handle, send LSA Query Info Policy requests, etc.
Using the Policy Handle, send an LSA Close.
Close the IPC$ share.

Defines for this pipe, identifying the query are:

LSA Open Policy:

0x2c

LSA Query Info Policy:

0x07

LSA Enumerate Trusted Domains:

0x0d

LSA Open Secret:

0xff

LSA Lookup SIDs:

0xfe

LSA Lookup Names:

0xfd

LSA Close:

0x00

LSA Open Policy

Note: The policy handle can be anything you like.

Request

VOID*

buffer pointer

UNISTR2

server name - unicode string starting with two '\'s

OBJ_ATTR

object attributes

UINT32

1 - desired access

Response

POL_HND

LSA policy handle

return

0 - indicates success

LSA Query Info Policy

Note: The info class in response must be the same as that in the request.

Request

POL_HND

LSA policy handle

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:
{
DOM_INFO domain info, levels 3 and 5 (are the same).
}

return    0 - indicates success

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

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

LSA Close

Request

POL_HND

policy handle to be closed

Response

POL_HND

0s - closed policy handle (all zeros)

return 0 - indicates success

LSA Lookup SIDS

Note: num_entries in response must be same as num_entries in request.

Request

POL_HND

LSA 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

DOM_REF

domain reference response

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

LSA Lookup Names

Note: num_entries in response must be same as num_entries in request.

Request

POL_HND

LSA 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

DOM_REF

domain reference response

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

NETLOGON rpc Transact Named Pipe

The sequence of actions taken on this pipe are:

tablish a connection to the IPC$ share (SMBtconX). use encrypted passwords.
en an RPC Pipe with the name "\\PIPE\\NETLOGON". Store the file handle.
ing the file handle, send a Set Named Pipe Handle state to 0x4300.
eate Client Challenge. Send LSA Request Challenge. Store Server Challenge.
lculate Session Key. Send an LSA Auth 2 Challenge. Store Auth2 Challenge.
lc/Verify Client Creds. Send LSA Srv PW Set. Calc/Verify Server Creds.
lc/Verify Client Creds. Send LSA SAM Logon . Calc/Verify Server Creds.
lc/Verify Client Creds. Send LSA SAM Logoff. Calc/Verify Server Creds.
ose the IPC$ share.

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 Auth 2:

0x0f

LSA Logon Control:

0x0e

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 becalls 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

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.

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

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)
{
	UINT16      3 - switch value indicating USER_INFO structure.
    VOID*     non-zero - pointer to USER_INFO structure
    USER_INFO user logon information

    UINT32    1 - Authoritative response; 0 - Non-Auth?

    return    0 - indicates success
}
else
{
	UINT16    0 - switch value.  value to indicate no user presumed.
    VOID*     0x0000 0000 - indicates no USER_INFO structure.

    UINT32    1 - Authoritative response; 0 - Non-Auth?

    return    0xC000 0064 - NT_STATUS_NO_SUCH_USER.
}

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.

return 0 - indicates success. undocumented failure indication.

\\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.

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)

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

SRVSVC Transact Named Pipe

Defines for this pipe, identifying the query are:

Net Share Enum

0x0f

Net Server Get Info

0x15

Net Share Enum

Note: share level and switch value in the response are presumably the same as those in the request.

Note: cifsrap2.txt (section 5) may be of limited assistance here.

Request

VOID*

pointer (to server name?)

UNISTR2

server name

UINT8[]

padding to get unicode string 4-byte aligned with the start of the SMB header.

UINT32

share level

UINT32

switch value

VOID*

pointer to SHARE_INFO_1_CTR

SHARE_INFO_1_CTR

share info with 0 entries

UINT32

preferred maximum length (0xffff ffff)

Response

UINT32

share level

UINT32

switch value

VOID*

pointer to SHARE_INFO_1_CTR

SHARE_INFO_1_CTR

share info (only added if share info ptr is non-zero)

return 0 - indicates success

Net Server Get Info

Note: level is the same value as in the request.

Request

UNISTR2

server name

UINT32

switch level

Response

UINT32

switch level

VOID*

pointer to SERVER_INFO_101

SERVER_INFO_101

server info (only added if server info ptr is non-zero)

return 0 - indicates success

Cryptographic side of NT Domain Authentication

Definitions

Add(A1,A2)

Intel byte ordered addition of corresponding 4 byte words in arrays A1 and A2

E(K,D)

DES ECB encryption of 8 byte data D using 7 byte key K

lmowf()

Lan man hash

ntowf()

NT hash

PW

md4(machine_password) == md4(lsadump $machine.acc) == pwdump(machine$) (initially) == md4(lmowf(unicode(machine)))

ARC4(K,Lk,D,Ld)

ARC4 encryption of data D of length Ld with key K of length Lk

v[m..n(,l)]

subset of v from bytes m to n, optionally padded with zeroes to length l

Cred(K,D)

E(K[7..7,7],E(K[0..6],D)) computes a credential

Time()

4 byte current time

Cc,Cs

8 byte client and server challenges Rc,Rs: 8 byte client and server credentials

Protocol

C->S ReqChal,Cc
S->C Cs
C & S compute session key Ks = E(PW[9..15],E(PW[0..6],Add(Cc,Cs)))
C: Rc = Cred(Ks,Cc)
C->S Authenticate,Rc
S: Rs = Cred(Ks,Cs), assert(Rc == Cred(Ks,Cc))
S->C Rs
C: assert(Rs == Cred(Ks,Cs))

On joining the domain the client will optionally attempt to change its password and the domain controller may refuse to update it depending on registry settings. This will also occur weekly afterwards.

C: Tc = Time(), Rc' = Cred(Ks,Rc+Tc)
C->S ServerPasswordSet,Rc',Tc,arc4(Ks[0..7,16],lmowf(randompassword())
C: Rc = Cred(Ks,Rc+Tc+1)
S: assert(Rc' == Cred(Ks,Rc+Tc)), Ts = Time()
S: Rs' = Cred(Ks,Rs+Tc+1)
S->C Rs',Ts
C: assert(Rs' == Cred(Ks,Rs+Tc+1))
S: Rs = Rs'

User: U with password P wishes to login to the domain (incidental data such as workstation and domain omitted)

C: Tc = Time(), Rc' = Cred(Ks,Rc+Tc)
C->S NetLogonSamLogon,Rc',Tc,U,arc4(Ks[0..7,16],16,ntowf(P),16), arc4(Ks[0..7,16],16,lmowf(P),16)
S: assert(Rc' == Cred(Ks,Rc+Tc)) assert(passwords match those in SAM)
S: Ts = Time()
S->C Cred(Ks,Cred(Ks,Rc+Tc+1)),userinfo(logon script,UID,SIDs,etc)
C: assert(Rs == Cred(Ks,Cred(Rc+Tc+1))
C: Rc = Cred(Ks,Rc+Tc+1)

Comments

On first joining the domain the session key could be computed by anyone listening in on the network as the machine password has a well known value. Until the machine is rebooted it will use this session key to encrypt NT and LM one way functions of passwords which are password equivalents. Any user who logs in before the machine has been rebooted a second time will have their password equivalent exposed. Of course the new machine password is exposed at this time anyway.

None of the returned user info such as logon script, profile path and SIDs *appear* to be protected by anything other than the TCP checksum.

The server time stamps appear to be ignored.

The client sends a ReturnAuthenticator in the SamLogon request which I can't find a use for. However its time is used as the timestamp returned by the server.

The password OWFs should NOT be sent over the network reversibly encrypted. They should be sent using ARC4(Ks,md4(owf)) with the server computing the same function using the owf values in the SAM.

SIDs and RIDs

SIDs and RIDs are well documented elsewhere.

A SID is an NT Security ID (see DOM_SID structure). They are of the form:

revision-NN-SubAuth1-SubAuth2-SubAuth3...
revision-0xNNNNNNNNNNNN-SubAuth1-SubAuth2-SubAuth3...

currently, the SID revision is 1. The Sub-Authorities are known as Relative IDs (RIDs).

Well-known SIDs

Universal well-known SIDs

Null SID

S-1-0-0

World

S-1-1-0

Local

S-1-2-0

Creator Owner ID

S-1-3-0

Creator Group ID

S-1-3-1

Creator Owner Server ID

S-1-3-2

Creator Group Server ID

S-1-3-3

(Non-unique IDs)

S-1-4

NT well-known SIDs

NT Authority

S-1-5

Dialup

S-1-5-1

Network

S-1-5-2

Batch

S-1-5-3

Interactive

S-1-5-4

Service

S-1-5-6

AnonymousLogon(aka null logon session)

S-1-5-7

Proxy

S-1-5-8

ServerLogon(aka domain controller account)

S-1-5-8

(Logon IDs)

S-1-5-5-X-Y

(NT non-unique IDs)

S-1-5-0x15-...

(Built-in domain)

s-1-5-0x20

Well-known RIDS

A RID is a sub-authority value, as part of either a SID, or in the case of Group RIDs, part of the DOM_GID structure, in the USER_INFO_1 structure, in the LSA SAM Logon response.

Well-known RID users

Groupname: DOMAIN_USER_RID_ADMIN
????: 0x0000
RID: 01F4
Groupname: DOMAIN_USER_RID_GUEST
????: 0x0000
RID: 01F5

Well-known RID groups

Groupname: DOMAIN_GROUP_RID_ADMINS
????: 0x0000
RID: 0200
Groupname: DOMAIN_GROUP_RID_USERS
????: 0x0000
RID: 0201
Groupname: DOMAIN_GROUP_RID_GUESTS
????: 0x0000
RID: 0202

Well-known RID aliases

Groupname: DOMAIN_ALIAS_RID_ADMINS
????: 0x0000
RID: 0220
Groupname: DOMAIN_ALIAS_RID_USERS
????: 0x0000
RID: 0221
Groupname: DOMAIN_ALIAS_RID_GUESTS
????: 0x0000
RID: 0222
Groupname: DOMAIN_ALIAS_RID_POWER_USERS
????: 0x0000
RID: 0223
Groupname: DOMAIN_ALIAS_RID_ACCOUNT_OPS
????: 0x0000
RID: 0224
Groupname: DOMAIN_ALIAS_RID_SYSTEM_OPS
????: 0x0000
RID: 0225
Groupname: DOMAIN_ALIAS_RID_PRINT_OPS
????: 0x0000
RID: 0226
Groupname: DOMAIN_ALIAS_RID_BACKUP_OPS
????: 0x0000
RID: 0227
Groupname: DOMAIN_ALIAS_RID_REPLICATOR
????: 0x0000
RID: 0228