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o [NSE] Added a new library for LDAP and two new scripts:
- ldap-brute uses the unpwdb library to guess credentials for LDAP - ldap-rootdse retrieves the LDAP root DSA-specific Entry (DSE)
This commit is contained in:
patrik
475
nselib/ldap.lua
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475
nselib/ldap.lua
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@@ -0,0 +1,475 @@
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--- Library methods for handling LDAP.
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--
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-- @author Patrik Karlsson
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-- @copyright Same as Nmap--See http://nmap.org/book/man-legal.html
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--
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-- Credit goes out to Martin Swende who provided me with the initial code that got me started writing this.
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--
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-- Version 0.3
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-- Created 01/12/2010 - v0.1 - Created by Patrik Karlsson <patrik@cqure.net>
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-- Revised 01/28/2010 - v0.2 - Revised to fit better fit ASN.1 library
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-- Revised 02/02/2010 - v0.3 - Revised to fit OO ASN.1 Library
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module("ldap", package.seeall)
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require("asn1")
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local ldapMessageId = 1
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ERROR_MSG = {}
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ERROR_MSG[1] = "Intialization of LDAP library failed."
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ERROR_MSG[4] = "Size limit exceeded."
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ERROR_MSG[32] = "No such object"
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ERROR_MSG[49] = "The supplied credential is invalid."
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ERRORS = {
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LDAP_SUCCESS = 0,
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LDAP_SIZELIMIT_EXCEEDED = 4
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}
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-- Application constants
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APPNO = {
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BindRequest = 0,
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BindResponse = 1,
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UnbindRequest = 2,
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SearchRequest = 3,
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SearchResponse = 4,
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SearchResDone = 5
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}
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-- Filter operation constants
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FILTER = {
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_and = 0,
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_or = 1,
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_not = 2,
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equalityMatch = 3,
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substrings = 4,
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greaterOrEqual = 5,
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lessOrEqual = 6,
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present = 7,
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approxMatch = 8,
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extensibleMatch = 9
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}
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-- Scope constants
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SCOPE = {
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base=0,
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one=1,
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sub= 2,
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children=3,
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default = 0
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}
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-- Deref policy constants
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DEREFPOLICY = {
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never=0,
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searching=1,
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finding = 2,
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always=3,
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default = 0
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}
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-- LDAP specific tag encoders
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local tagEncoder = {}
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tagEncoder['table'] = function(self, val)
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if (val._ldap == '0A') then
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local ival = self.encodeInt(val[1])
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local len = self.encodeLength(string.len(ival))
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return bin.pack('HAA', '0A', len, ival)
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end
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if (val._ldaptype) then
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local len
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if val[1] == nil or string.len(val[1]) == 0 then
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return bin.pack('HC', val._ldaptype, 0)
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else
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len = self.encodeLength(string.len(val[1]))
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return bin.pack('HAA', val._ldaptype, len, val[1])
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end
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end
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local encVal = ""
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for _, v in ipairs(val) do
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encVal = encVal .. encode(v) -- todo: buffer?
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end
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local tableType = bin.pack("H", "30")
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if (val["_snmp"]) then
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tableType = bin.pack("H", val["_snmp"])
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end
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return bin.pack('AAA', tableType, self.encodeLength(string.len(encVal)), encVal)
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end
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---
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-- Encodes a given value according to ASN.1 basic encoding rules for SNMP
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-- packet creation.
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-- @param val Value to be encoded.
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-- @return Encoded value.
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function encode(val)
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local encoder = asn1.ASN1Encoder:new()
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local encValue
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encoder:registerTagEncoders(tagEncoder)
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encValue = encoder:encode(val)
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if encValue then
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return encValue
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end
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return ''
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end
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-- LDAP specific tag decoders
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local tagDecoder = {}
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tagDecoder["0A"] = function( self, encStr, elen, pos )
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return self.decodeInt(encStr, elen, pos)
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end
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-- null decoder
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tagDecoder["31"] = function( self, encStr, elen, pos )
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return pos, nil
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end
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---
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-- Decodes an LDAP packet or a part of it according to ASN.1 basic encoding
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-- rules.
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-- @param encStr Encoded string.
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-- @param pos Current position in the string.
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-- @return The position after decoding
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-- @return The decoded value(s).
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function decode(encStr, pos)
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-- register the LDAP specific tag decoders
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local decoder = asn1.ASN1Decoder:new()
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decoder:registerTagDecoders( tagDecoder )
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return decoder:decode( encStr, pos )
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end
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---
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-- Decodes a sequence according to ASN.1 basic encoding rules.
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-- @param encStr Encoded string.
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-- @param len Length of sequence in bytes.
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-- @param pos Current position in the string.
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-- @return The position after decoding.
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-- @return The decoded sequence as a table.
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local function decodeSeq(encStr, len, pos)
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local seq = {}
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local sPos = 1
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local sStr
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pos, sStr = bin.unpack("A" .. len, encStr, pos)
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if(sStr==nil) then
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return pos,seq
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end
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while (sPos < len) do
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local newSeq
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sPos, newSeq = decode(sStr, sPos)
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table.insert(seq, newSeq)
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end
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return pos, seq
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end
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-- Encodes an LDAP Application operation and its data as a sequence
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--
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-- @param appno LDAP application number @see <code>APPNO</code>
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-- @param isConstructed boolean true if constructed, false if primitive
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-- @param data string containing the LDAP operation content
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-- @return string containing the encoded LDAP operation
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function encodeLDAPOp( appno, isConstructed, data )
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local encoded_str = ""
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local asn1_type = asn1.BERtoInt( asn1.BERCLASS.Application, isConstructed, appno )
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encoded_str = encode( { _ldaptype = bin.pack("A", string.format("%X", asn1_type)), data } )
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return encoded_str
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end
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--- Performs an LDAP Search request
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--
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-- This function has a concept of softerrors which populates the return tables error information
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-- while returning a true status. The reason for this is that LDAP may return a number of records
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-- and then finnish of with an error like SIZE LIMIT EXCEEDED. We still want to return the records
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-- that were received prior to the error. In order to achieve this and not terminating the script
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-- by returning a false status a true status is returned together with a table containing all searchentries.
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-- This table has the <code>errorMessage</code> and <code>resultCode</code> entries set with the error information.
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-- As a <code>try</code> won't catch this error it's up to the script to do so. @see ldap-search.nse for an example.
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--
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-- @param socket socket already connected to the ldap server
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-- @param params table containing at least <code>scope</code>, <code>derefPolicy</code>, <code>baseObject</code>
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-- the field <code>maxObjects</code> may also be included to restrict the amount of records returned
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-- @return success true or false.
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-- @return err string containing error message
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function searchRequest( socket, params )
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local searchResEntries = { errorMessage="", resultCode = 0}
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local catch = function() socket:close() stdnse.print_debug(string.format("SearchRequest failed")) end
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local try = nmap.new_try(catch)
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local attributes = params.attributes
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local request = encode(params.baseObject)
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local attrSeq = ''
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local requestData, messageSeq, data
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local maxObjects = params.maxObjects or -1
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local encoder = asn1.ASN1Encoder:new()
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local decoder = asn1.ASN1Decoder:new()
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encoder:registerTagEncoders(tagEncoder)
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decoder:registerTagDecoders(tagDecoder)
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request = request .. encode( { _ldap='0A', params.scope } )--scope
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request = request .. encode( { _ldap='0A', params.derefPolicy } )--derefpolicy
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request = request .. encode( params.sizeLimit or 0)--sizelimit
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request = request .. encode( params.timeLimit or 0)--timelimit
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request = request .. encode( params.typesOnly or false)--TypesOnly
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if params.filter then
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request = request .. createFilter( params.filter )
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else
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request = request .. encode( { _ldaptype='87', "objectclass" } )-- filter : string, presence
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end
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if attributes~= nil then
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for _,attr in ipairs(attributes) do
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attrSeq = attrSeq .. encode(attr)
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end
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end
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request = request .. encoder:encodeSeq(attrSeq)
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requestData = encodeLDAPOp(APPNO.SearchRequest, true, request)
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messageSeq = encode(ldapMessageId)
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ldapMessageId = ldapMessageId +1
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messageSeq = messageSeq .. requestData
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data = encoder:encodeSeq(messageSeq)
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try( socket:send( data ) )
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data = ""
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while true do
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local len, pos, messageId = 0, 2, -1
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local tmp = ""
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local _, objectName, attributes, ldapOp
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local attributes
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local searchResEntry = {}
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if ( maxObjects == 0 ) then
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break
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elseif ( maxObjects > 0 ) then
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maxObjects = maxObjects - 1
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end
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if data:len() > 6 then
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pos, len = decoder.decodeLength( data, pos )
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else
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data = data .. try( socket:receive() )
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pos, len = decoder.decodeLength( data, pos )
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end
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-- pos should be at the right position regardless if length is specified in 1 or 2 bytes
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while ( len + pos - 1 > data:len() ) do
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data = data .. try( socket:receive() )
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end
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pos, messageId = decode( data, pos )
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pos, tmp = bin.unpack("C", data, pos)
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pos, len = decoder.decodeLength( data, pos )
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ldapOp = asn1.intToBER( tmp )
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searchResEntry = {}
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if ldapOp.number == APPNO.SearchResDone then
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pos, searchResEntry.resultCode = decode( data, pos )
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-- errors may occur after a large amount of data has been received (eg. size limit exceeded)
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-- we want to be able to return the data received prior to this error to the user
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-- however, we also need to alert the user of the error. This is achieved through "softerrors"
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-- softerrors populate the error fields of the table while returning a true status
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-- this allows for the caller to output data while still being able to catch the error
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if ( searchResEntry.resultCode ~= 0 ) then
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local error_msg
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pos, searchResEntry.matchedDN = decode( data, pos )
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pos, searchResEntry.errorMessage = decode( data, pos )
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error_msg = ERROR_MSG[searchResEntry.resultCode]
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-- if the table is empty return a hard error
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if #searchResEntries == 0 then
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return false, string.format("Code: %d|Error: %s|Details: %s", searchResEntry.resultCode, error_msg or "", searchResEntry.errorMessage or "" )
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else
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searchResEntries.errorMessage = string.format("Code: %d|Error: %s|Details: %s", searchResEntry.resultCode, error_msg or "", searchResEntry.errorMessage or "" )
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searchResEntries.resultCode = searchResEntry.resultCode
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return true, searchResEntries
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end
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end
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break
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end
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pos, searchResEntry.objectName = decode( data, pos )
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if ldapOp.number == APPNO.SearchResponse then
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pos, searchResEntry.attributes = decode( data, pos )
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table.insert( searchResEntries, searchResEntry )
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end
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if data:len() > pos then
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data = data:sub(pos)
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else
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data = ""
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end
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end
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return true, searchResEntries
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end
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--- Attempts to bind to the server using the credentials given
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--
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-- @param socket socket already connected to the ldap server
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-- @param params table containing <code>version</code>, <code>username</code> and <code>password</code>
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-- @return success true or false
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-- @return err string containing error message
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function bindRequest( socket, params )
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local catch = function() socket:close() stdnse.print_debug(string.format("bindRequest failed")) end
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local try = nmap.new_try(catch)
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local ldapAuth = encode( { _ldaptype = 80, params.password } )
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local bindReq = encode( params.version ) .. encode( params.username ) .. ldapAuth
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local ldapMsg = encode(ldapMessageId) .. encodeLDAPOp( APPNO.BindRequest, true, bindReq )
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local packet
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local pos, packet_len, resultCode, tmp, len, _
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local response = {}
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local encoder = asn1.ASN1Encoder:new()
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local decoder = asn1.ASN1Decoder:new()
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encoder:registerTagEncoders(tagEncoder)
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decoder:registerTagDecoders(tagDecoder)
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packet = encoder:encodeSeq( ldapMsg )
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ldapMessageId = ldapMessageId +1
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try( socket:send( packet ) )
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packet = try( socket:receive() )
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pos, packet_len = decoder.decodeLength( packet, 2 )
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pos, response.messageID = decode( packet, pos )
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pos, tmp = bin.unpack("C", packet, pos)
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pos, len = decoder.decodeLength( packet, pos )
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response.protocolOp = asn1.intToBER( tmp )
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if response.protocolOp.number ~= APPNO.BindResponse then
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return false, string.format("Recieved incorrect Op in packet: %d, expected %d", response.protocolOp.number, APPNO.BindResponse)
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end
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pos, response.resultCode = decode( packet, pos )
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if ( response.resultCode ~= 0 ) then
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local error_msg
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pos, response.matchedDN = decode( packet, pos )
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pos, response.errorMessage = decode( packet, pos )
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error_msg = ERROR_MSG[response.resultCode]
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return false, string.format("Error: %s\nDetails: %s", error_msg or "", response.errorMessage or "" )
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else
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return true, "Success"
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end
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end
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--- Performs an LDAP Unbind
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--
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-- @param socket socket already connected to the ldap server
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-- @return success true or false
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-- @return err string containing error message
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function unbindRequest( socket )
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local ldapMsg, packet
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local catch = function() socket:close() stdnse.print_debug(string.format("bindRequest failed")) end
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local try = nmap.new_try(catch)
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local encoder = asn1.ASN1Encoder:new()
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encoder:registerTagEncoders(tagEncoder)
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ldapMessageId = ldapMessageId +1
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ldapMsg = encode( ldapMessageId )
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ldapMsg = ldapMsg .. encodeLDAPOp( APPNO.UnbindRequest, false, nil)
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packet = encoder:encodeSeq( ldapMsg )
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try( socket:send( packet ) )
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return true, ""
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end
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--- Creates an ASN1 structure from a filter table
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--
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-- @param filter table containing the filter to be created
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-- @return string containing the ASN1 byte sequence
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function createFilter( filter )
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local asn1_type = asn1.BERtoInt( asn1.BERCLASS.ContextSpecific, true, filter.op )
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local filter_str = ""
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if type(filter.val) == 'table' then
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for _, v in ipairs( filter.val ) do
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filter_str = filter_str .. createFilter( v )
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end
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else
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local obj = encode( filter.obj )
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local val = encode( filter.val )
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filter_str = filter_str .. obj .. val
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end
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return encode( { _ldaptype=bin.pack("A", string.format("%X", asn1_type)), filter_str } )
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end
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--- Converts a search result as received from searchRequest to a "result" table
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--
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-- Does some limited decoding of LDAP attributes
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--
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-- TODO: Add decoding of missing attributes
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-- TODO: Add decoding of userParameters
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-- TODO: Add decoding of loginHours
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--
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-- @param searchEntries table as returned from searchRequest
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-- @return table suitable for <code>stdnse.format_output</code>
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function searchResultToTable( searchEntries )
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local result = {}
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for _, v in ipairs( searchEntries ) do
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local result_part = {}
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if v.objectName and v.objectName:len() > 0 then
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result_part.name = string.format("dn: %s", v.objectName)
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else
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result_part.name = "<ROOT>"
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end
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local attribs = {}
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if ( v.attributes ~= nil ) then
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for _, attrib in ipairs( v.attributes ) do
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for i=2, #attrib do
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-- do some additional Windows decoding
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if ( attrib[1] == "objectSid" ) then
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table.insert( attribs, string.format( "%s: %d", attrib[1], decode( attrib[i] ) ) )
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elseif ( attrib[1] == "objectGUID") then
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local _, o1, o2, o3, o4, o5, o6, o7, o8, o9, oa, ob, oc, od, oe, of = bin.unpack("C16", attrib[i] )
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table.insert( attribs, string.format( "%s: %x%x%x%x-%x%x-%x%x-%x%x-%x%x%x%x%x", attrib[1], o4, o3, o2, o1, o5, o6, o7, o8, o9, oa, ob, oc, od, oe, of ) )
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else
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table.insert( attribs, string.format( "%s: %s", attrib[1], attrib[i] ) )
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end
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||||
end
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end
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table.insert( result_part, attribs )
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end
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table.insert( result, result_part )
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end
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return result
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||||
end
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||||
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||||
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||||
--- Extract naming context from a search response
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||||
--
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||||
-- @param searchEntries table containing searchEntries from a searchResponse
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||||
-- @param attributeName string containing the attribute to extract
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||||
-- @return table containing the attribute values
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||||
function extractAttribute( searchEntries, attributeName )
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||||
local attributeTbl = {}
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for _, v in ipairs( searchEntries ) do
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||||
if ( v.attributes ~= nil ) then
|
||||
for _, attrib in ipairs( v.attributes ) do
|
||||
local attribType = attrib[1]
|
||||
for i=2, #attrib do
|
||||
if attribType == attributeName then
|
||||
table.insert( attributeTbl, attrib[i])
|
||||
end
|
||||
end
|
||||
end
|
||||
end
|
||||
end
|
||||
return ( #attributeTbl > 0 and attributeTbl or nil )
|
||||
end
|
||||
Reference in New Issue
Block a user