sqlmap/lib/controller/checks.py

#!/usr/bin/env python

"""
$Id$

Copyright (c) 2006-2010 sqlmap developers (http://sqlmap.sourceforge.net/)
See the file 'doc/COPYING' for copying permission
"""

import re
import socket
import time

from difflib import SequenceMatcher

from lib.core.agent import agent
from lib.core.common import beep
from lib.core.common import calculateDeltaSeconds
from lib.core.common import getUnicode
from lib.core.common import randomInt
from lib.core.common import randomStr
from lib.core.common import readInput
from lib.core.common import showStaticWords
from lib.core.common import trimAlphaNum
from lib.core.common import wasLastRequestDBMSError
from lib.core.common import DynamicContentItem
from lib.core.data import conf
from lib.core.data import kb
from lib.core.data import logger
from lib.core.data import paths
from lib.core.datatype import advancedDict
from lib.core.datatype import injectionDict
from lib.core.enums import HTTPMETHOD
from lib.core.enums import NULLCONNECTION
from lib.core.enums import PAYLOAD
from lib.core.exception import sqlmapConnectionException
from lib.core.exception import sqlmapGenericException
from lib.core.exception import sqlmapNoneDataException
from lib.core.exception import sqlmapSiteTooDynamic
from lib.core.exception import sqlmapUserQuitException
from lib.core.session import setString
from lib.core.session import setRegexp
from lib.core.settings import ERROR_SPACE
from lib.core.settings import ERROR_EMPTY_CHAR
from lib.request.connect import Connect as Request
from plugins.dbms.firebird.syntax import Syntax as Firebird
from plugins.dbms.postgresql.syntax import Syntax as PostgreSQL
from plugins.dbms.mssqlserver.syntax import Syntax as MSSQLServer
from plugins.dbms.oracle.syntax import Syntax as Oracle
from plugins.dbms.mysql.syntax import Syntax as MySQL
from plugins.dbms.access.syntax import Syntax as Access
from plugins.dbms.sybase.syntax import Syntax as Sybase
from plugins.dbms.sqlite.syntax import Syntax as SQLite
from plugins.dbms.maxdb.syntax import Syntax as MaxDB


def unescape(string, dbms):
    unescaper = {
                  "Access": Access.unescape,
                  "Firebird": Firebird.unescape,
                  "MaxDB": MaxDB.unescape,
                  "Microsoft SQL Server": MSSQLServer.unescape,
                  "MySQL": MySQL.unescape,
                  "Oracle": Oracle.unescape,
                  "PostgreSQL": PostgreSQL.unescape,
                  "SQLite": SQLite.unescape,
                  "Sybase": Sybase.unescape
                }

    if dbms in unescaper:
        return unescaper[dbms](string)
    else:
        return string

def unescapeDbms(payload, injection, dbms):
    # If this is a DBMS-specific test (dbms), sqlmap identified the
    # DBMS during previous a test (injection.dbms) or the user
    # provided a DBMS (conf.dbms), unescape the strings between single
    # quotes in the payload
    if injection.dbms is not None:
        payload = unescape(payload, injection.dbms)
    elif dbms is not None:
        payload = unescape(payload, dbms)
    elif conf.dbms is not None:
        payload = unescape(payload, conf.dbms)

    return payload

def checkSqlInjection(place, parameter, value):
    # Store here the details about boundaries and payload used to
    # successfully inject
    injection = injectionDict()

    for test in conf.tests:
        title = test.title
        stype = test.stype

        # Skip test if the risk is higher than the provided (or default)
        # value
        # Parse test's <risk>
        if test.risk > conf.risk:
            debugMsg = "skipping test '%s' because the risk " % title
            debugMsg += "is higher than the provided"
            logger.debug(debugMsg)
            continue

        # Skip test if the level is higher than the provided (or default)
        # value
        # Parse test's <level>
        if test.level > conf.level:
            debugMsg = "skipping test '%s' because the level " % title
            debugMsg += "is higher than the provided"
            logger.debug(debugMsg)
            continue

        # Skip DBMS-specific test if it does not match either the
        # previously identified or the user's provided DBMS
        if "details" in test and "dbms" in test.details:
            dbms = test.details.dbms
        else:
            dbms = None

        if dbms is not None:
            if injection.dbms is not None and injection.dbms != dbms:
                debugMsg = "skipping test '%s' because " % title
                debugMsg += "the back-end DBMS identified is "
                debugMsg += "%s" % injection.dbms
                logger.debug(debugMsg)

                continue

            if conf.dbms is not None and conf.dbms.lower() != dbms.lower():
                debugMsg = "skipping test '%s' because " % title
                debugMsg += "the provided DBMS is %s" % conf.dbms
                logger.debug(debugMsg)

                continue

        # Skip test if it is the same SQL injection type already
        # identified by another test
        if injection.data and stype in injection.data:
            debugMsg = "skipping test '%s' because " % title
            debugMsg += "the payload for %s has " % PAYLOAD.SQLINJECTION[stype]
            debugMsg += "already been identified"
            logger.debug(debugMsg)
            continue

        infoMsg = "testing '%s'" % title
        logger.info(infoMsg)

        # Parse test's <request>
        comment = agent.getComment(test.request)
        fstPayload = agent.cleanupPayload(test.request.payload)
        fstPayload = unescapeDbms(fstPayload, injection, dbms)
        fstPayload = "%s%s" % (fstPayload, comment)

        if conf.prefix is not None and conf.suffix is not None:
            # Create a custom boundary object for user's supplied prefix
            # and suffix
            boundary = advancedDict()

            boundary.level = 1
            boundary.clause = [ 0 ]
            boundary.where = [ 1, 2, 3 ]
            boundary.prefix = conf.prefix
            boundary.suffix = conf.suffix

            if " like" in boundary.suffix.lower():
                if "'" in boundary.suffix.lower():
                    boundary.ptype = 3
                elif '"' in boundary.suffix.lower():
                    boundary.ptype = 5
            elif "'" in boundary.suffix.lower():
                boundary.ptype = 2
            elif '"' in boundary.suffix.lower():
                boundary.ptype = 4
            else:
                boundary.ptype = 1

            # Prepend user's provided boundaries to all others boundaries
            conf.boundaries.insert(0, boundary)

        for boundary in conf.boundaries:
            injectable = False

            # Skip boundary if the level is higher than the provided (or
            # default) value
            # Parse boundary's <level>
            if boundary.level > conf.level:
                # NOTE: shall we report every single skipped boundary too?
                continue

            # Skip boundary if it does not match against test's <clause>
            # Parse test's <clause> and boundary's <clause>
            clauseMatch = False

            for clauseTest in test.clause:
                if clauseTest in boundary.clause:
                    clauseMatch = True
                    break

            if test.clause != [ 0 ] and boundary.clause != [ 0 ] and not clauseMatch:
                continue

            # Skip boundary if it does not match against test's <where>
            # Parse test's <where> and boundary's <where>
            whereMatch = False

            for where in test.where:
                if where in boundary.where:
                    whereMatch = True
                    break

            if not whereMatch:
                continue

            # Parse boundary's <prefix>, <suffix> and <ptype>
            prefix = boundary.prefix if boundary.prefix else ""
            suffix = boundary.suffix if boundary.suffix else ""
            ptype = boundary.ptype

            # If the previous injections succeeded, we know which prefix,
            # suffix and parameter type to use for further tests, no
            # need to cycle through the boundaries for the following tests
            condBound = (injection.prefix is not None and injection.suffix is not None)
            condBound &= (injection.prefix != prefix or injection.suffix != suffix)
            condType = injection.ptype is not None and injection.ptype != ptype

            if condBound or condType:
                continue

            # For each test's <where>
            for where in test.where:
                # Threat the parameter original value according to the
                # test's <where> tag
                if where == 1:
                    origValue = value
                elif where == 2:
                    origValue = "-%s" % value
                elif where == 3:
                    origValue = ""

                # Forge request payload by prepending with boundary's
                # prefix and appending the boundary's suffix to the
                # test's ' <payload><comment> ' string
                boundPayload = "%s%s %s %s" % (origValue, prefix, fstPayload, suffix)
                boundPayload = boundPayload.strip()
                boundPayload = agent.cleanupPayload(boundPayload)
                reqPayload = agent.payload(place, parameter, value, boundPayload)

                # Perform the test's request and check whether or not the
                # payload was successful
                # Parse test's <response>
                for method, check in test.response.items():
                    check = agent.cleanupPayload(check)

                    # In case of boolean-based blind SQL injection
                    if method == "comparison":
                        sndPayload = agent.cleanupPayload(test.response.comparison)
                        sndPayload = unescapeDbms(sndPayload, injection, dbms)
                        sndPayload = "%s%s" % (sndPayload, comment)

                        # Forge response payload by prepending with
                        # boundary's prefix and appending the boundary's
                        # suffix to the test's ' <payload><comment> '
                        # string
                        boundPayload = "%s%s %s %s" % (origValue, prefix, sndPayload, suffix)
                        boundPayload = boundPayload.strip()
                        boundPayload = agent.cleanupPayload(boundPayload)
                        cmpPayload = agent.payload(place, parameter, value, boundPayload)

                        # Useful to set conf.matchRatio at first based on
                        # the False response content
                        conf.matchRatio = None
                        _ = Request.queryPage(cmpPayload, place)

                        # Compare True and False response contents
                        trueResult = Request.queryPage(reqPayload, place)

                        if trueResult:
                            falseResult = Request.queryPage(cmpPayload, place)

                            if not falseResult:
                                infoMsg = "%s parameter '%s' is '%s' injectable " % (place, parameter, title)
                                logger.info(infoMsg)

                                kb.paramMatchRatio[(place, parameter)] = conf.matchRatio
                                injectable = True

                        kb.paramMatchRatio[(place, parameter)] = conf.matchRatio

                    # In case of error-based or UNION query SQL injections
                    elif method == "grep":
                        # Perform the test's request and grep the response
                        # body for the test's <grep> regular expression
                        reqBody, _ = Request.queryPage(reqPayload, place, content=True)
                        match = re.search(check, reqBody, re.DOTALL | re.IGNORECASE)

                        if not match:
                            continue

                        output = match.group('result')

                        if output:
                            output = output.replace(ERROR_SPACE, " ").replace(ERROR_EMPTY_CHAR, "")

                        if output == "1":
                            infoMsg = "%s parameter '%s' is '%s' injectable " % (place, parameter, title)
                            logger.info(infoMsg)

                            injectable = True

                    # In case of time-based blind or stacked queries
                    # SQL injections
                    elif method == "time":
                        # Perform the test's request and check how long
                        # it takes to get the response back
                        start = time.time()
                        _ = Request.queryPage(reqPayload, place)
                        duration = calculateDeltaSeconds(start)

                        if duration >= conf.timeSec:
                            infoMsg = "%s parameter '%s' is '%s' injectable " % (place, parameter, title)
                            logger.info(infoMsg)

                            injectable = True

                # If the injection test was successful feed the injection
                # object with the test's details
                if injectable is True:
                    # Feed with the boundaries details only the first time a
                    # test has been successful
                    if injection.place is None or injection.parameter is None:
                        injection.place = place
                        injection.parameter = parameter
                        injection.ptype = ptype
                        injection.prefix = prefix
                        injection.suffix = suffix

                    # Feed with test details every time a test is successful
                    injection.data[stype] = (title, reqPayload, where, comment)

                    if "details" in test:
                        for detailKey, detailValue in test.details.items():
                            if detailKey == "dbms" and injection.dbms is None:
                                injection.dbms = detailValue
                                kb.dbms = detailValue
                            elif detailKey == "dbms_version" and injection.dbms_version is None:
                                injection.dbms_version = detailValue
                                kb.dbmsVersion = [ detailValue ]
                            elif detailKey == "os" and injection.os is None:
                                injection.os = detailValue

                    beep()

                    # There is no need to perform this test for other
                    # <where> tags
                    break

            if injectable is True:
                # There is no need to perform this test with others
                # boundaries
                break

    # Return the injection object
    if injection.place is not None and injection.parameter is not None:
        return injection
    else:
        return None

def heuristicCheckSqlInjection(place, parameter, value):
    if kb.nullConnection:
        debugMsg  = "heuristic checking skipped "
        debugMsg += "because NULL connection used"
        logger.debug(debugMsg)
        return

    prefix = ""
    suffix = ""

    if conf.prefix or conf.suffix:
        if conf.prefix:
            prefix = conf.prefix

        if conf.suffix:
            suffix = conf.suffix

    payload = "%s%s%s%s" % (value, prefix, randomStr(length=10, alphabet=['"', '\'', ')', '(']), suffix)
    payload = agent.payload(place, parameter, value, payload)
    Request.queryPage(payload, place, raise404=False)
    result = wasLastRequestDBMSError()

    infoMsg  = "heuristics shows that %s " % place
    infoMsg += "parameter '%s' might " % parameter

    if result:
        infoMsg += "be injectable (possible DBMS: %s)" % (kb.htmlFp[-1] if kb.htmlFp else 'Unknown')
        logger.info(infoMsg)
    else:
        infoMsg += "not be injectable"
        logger.warning(infoMsg)

def checkDynParam(place, parameter, value):
    """
    This function checks if the url parameter is dynamic. If it is
    dynamic, the content of the page differs, otherwise the
    dynamicity might depend on another parameter.
    """

    conf.matchRatio = None

    infoMsg = "testing if %s parameter '%s' is dynamic" % (place, parameter)
    logger.info(infoMsg)

    randInt = randomInt()
    payload = agent.payload(place, parameter, value, getUnicode(randInt))
    dynResult = Request.queryPage(payload, place)

    if True == dynResult:
        return False

    infoMsg = "confirming that %s parameter '%s' is dynamic" % (place, parameter)
    logger.info(infoMsg)

    randInt = randomInt()
    payload = agent.payload(place, parameter, value, getUnicode(randInt))
    dynResult = Request.queryPage(payload, place)

    return not dynResult

def checkDynamicContent(firstPage, secondPage):
    """
    This function checks if the provided pages have dynamic content. If they
    are dynamic, proper markings will be made.
    """

    if kb.nullConnection:
        debugMsg  = "dynamic content checking skipped "
        debugMsg += "because NULL connection used"
        logger.debug(debugMsg)
        return

    if conf.longestCommon:
        debugMsg  = "dynamic content checking skipped "
        debugMsg += "because longest common comparison used"
        logger.debug(debugMsg)
        return

    infoMsg = "searching for dynamic content"
    logger.info(infoMsg)

    blocks = SequenceMatcher(None, firstPage, secondPage).get_matching_blocks()
    kb.dynamicMarkings = []

    i = 0
    while i < len(blocks):
        block = blocks[i]
        (_, _, length) = block

        if length <= conf.minMatchBlock:
            blocks.remove(block)

        else:
            i += 1

    if len(blocks) > 0:
        blocks.insert(0, None)
        blocks.append(None)

        for i in xrange(len(blocks) - 1):
            prefix = firstPage[blocks[i][0]:blocks[i][0] + blocks[i][2]] if blocks[i] else None
            suffix = firstPage[blocks[i + 1][0]:blocks[i + 1][0] + blocks[i + 1][2]] if blocks[i + 1] else None

            if prefix is None and blocks[i + 1][0] == 0:
                continue

            if suffix is None and (blocks[i][0] + blocks[i][2] >= len(firstPage)):
                continue

            prefix = trimAlphaNum(prefix)
            suffix = trimAlphaNum(suffix)

            kb.dynamicMarkings.append((re.escape(prefix[-conf.dynMarkLength:]) if prefix else None, re.escape(suffix[:conf.dynMarkLength]) if suffix else None))

    if len(kb.dynamicMarkings) > 0:
        infoMsg = "dynamic content marked for removal (%d region%s)" % (len(kb.dynamicMarkings), 's' if len(kb.dynamicMarkings) > 1 else '')
        logger.info(infoMsg)

        if conf.seqMatcher.a:
            for item in kb.dynamicMarkings:
                prefix, suffix = item

                if prefix is None:
                    conf.seqMatcher.a = re.sub('(?s)^.+%s' % suffix, suffix, conf.seqMatcher.a)
                elif suffix is None:
                    conf.seqMatcher.a = re.sub('(?s)%s.+$' % prefix, prefix, conf.seqMatcher.a)
                else:
                    conf.seqMatcher.a = re.sub('(?s)%s.+%s' % (prefix, suffix), '%s%s' % (prefix, suffix), conf.seqMatcher.a)

def checkStability():
    """
    This function checks if the URL content is stable requesting the
    same page two times with a small delay within each request to
    assume that it is stable.

    In case the content of the page differs when requesting
    the same page, the dynamicity might depend on other parameters,
    like for instance string matching (--string).
    """

    infoMsg = "testing if the url is stable, wait a few seconds"
    logger.info(infoMsg)

    firstPage = conf.seqMatcher.a # set inside checkConnection()
    time.sleep(1)
    secondPage, _ = Request.queryPage(content=True)

    kb.pageStable = (firstPage == secondPage)

    if kb.pageStable:
        if firstPage:
            logMsg  = "url is stable"
            logger.info(logMsg)
        else:
            errMsg  = "there was an error checking the stability of page "
            errMsg += "because of lack of content. please check the "
            errMsg += "page request results (and probable errors) by "
            errMsg += "using higher verbosity levels"
            raise sqlmapNoneDataException, errMsg

    else:
        warnMsg  = "url is not stable, sqlmap will base the page "
        warnMsg += "comparison on a sequence matcher. If no dynamic nor "
        warnMsg += "injectable parameters are detected, or in case of "
        warnMsg += "junk results, refer to user's manual paragraph "
        warnMsg += "'Page comparison' and provide a string or regular "
        warnMsg += "expression to match on"
        logger.warn(warnMsg)

        message = "how do you want to proceed? [C(ontinue)/s(tring)/r(egex)/q(uit)] "
        test = readInput(message, default="C")

        if test and test[0] in ("q", "Q"):
            raise sqlmapUserQuitException

        elif test and test[0] in ("s", "S"):
            showStaticWords(firstPage, secondPage)

            message = "please enter value for parameter 'string': "
            test = readInput(message)

            if test:
                conf.string = test

                if kb.nullConnection:
                    debugMsg  = "turning off NULL connection "
                    debugMsg += "support because of string checking"
                    logger.debug(debugMsg)

                    kb.nullConnection = None
            else:
                errMsg = "Empty value supplied"
                raise sqlmapNoneDataException, errMsg

        elif test and test[0] in ("r", "R"):
            message = "please enter value for parameter 'regex': "
            test = readInput(message)

            if test:
                conf.regex = test

                if kb.nullConnection:
                    debugMsg  = "turning off NULL connection "
                    debugMsg += "support because of regex checking"
                    logger.debug(debugMsg)

                    kb.nullConnection = None
            else:
                errMsg = "Empty value supplied"
                raise sqlmapNoneDataException, errMsg
        else:
            checkDynamicContent(firstPage, secondPage)

            count = 0
            while not Request.queryPage():
                count += 1

                if count > conf.retries:
                    errMsg = "target url is too dynamic. unable to continue. "
                    errMsg += "consider using other switches (e.g. "
                    errMsg += "--longest-common, --string, --text-only, etc.)"
                    raise sqlmapSiteTooDynamic, errMsg

                warnMsg = "target url is heavily dynamic"
                warnMsg += ", sqlmap is going to retry the request"
                logger.critical(warnMsg)

                secondPage, _ = Request.queryPage(content=True)
                checkDynamicContent(firstPage, secondPage)

    return kb.pageStable

def checkString():
    if not conf.string:
        return True

    condition = (
                  kb.resumedQueries.has_key(conf.url) and
                  kb.resumedQueries[conf.url].has_key("String") and
                  kb.resumedQueries[conf.url]["String"][:-1] == conf.string
                )

    if condition:
        return True

    infoMsg  = "testing if the provided string is within the "
    infoMsg += "target URL page content"
    logger.info(infoMsg)

    page, _ = Request.queryPage(content=True)

    if conf.string in page:
        setString()
    else:
        warnMsg  = "you provided '%s' as the string to " % conf.string
        warnMsg += "match, but such a string is not within the target "
        warnMsg += "URL page content original request, sqlmap will "
        warnMsg += "keep going anyway"
        logger.warn(warnMsg)

    return True

def checkRegexp():
    if not conf.regexp:
        return True

    condition = (
                  kb.resumedQueries.has_key(conf.url) and
                  kb.resumedQueries[conf.url].has_key("Regular expression") and
                  kb.resumedQueries[conf.url]["Regular expression"][:-1] == conf.regexp
                )

    if condition:
        return True

    infoMsg  = "testing if the provided regular expression matches within "
    infoMsg += "the target URL page content"
    logger.info(infoMsg)

    page, _ = Request.queryPage(content=True)

    if re.search(conf.regexp, page, re.I | re.M):
        setRegexp()
    else:
        warnMsg  = "you provided '%s' as the regular expression to " % conf.regexp
        warnMsg += "match, but such a regular expression does not have any "
        warnMsg += "match within the target URL page content, sqlmap "
        warnMsg += "will keep going anyway"
        logger.warn(warnMsg)

    return True

def checkNullConnection():
    """
    Reference: http://www.wisec.it/sectou.php?id=472f952d79293
    """

    infoMsg = "testing NULL connection to the target url"
    logger.info(infoMsg)

    try:
        page, headers = Request.getPage(method=HTTPMETHOD.HEAD)
        if not page and 'Content-Length' in headers:
            kb.nullConnection = NULLCONNECTION.HEAD

            infoMsg = "NULL connection is supported with HEAD header"
            logger.info(infoMsg)
        else:
            page, headers = Request.getPage(auxHeaders={"Range": "bytes=-1"})
            if page and len(page) == 1 and 'Content-Range' in headers:
                kb.nullConnection = NULLCONNECTION.RANGE

                infoMsg = "NULL connection is supported with GET header "
                infoMsg += "'%s'" % kb.nullConnection
                logger.info(infoMsg)
    except sqlmapConnectionException, errMsg:
        errMsg = getUnicode(errMsg)
        raise sqlmapConnectionException, errMsg

    return kb.nullConnection is not None

def checkConnection(suppressOutput=False):
    try:
        socket.gethostbyname(conf.hostname)
    except socket.gaierror:
        errMsg = "host '%s' does not exist" % conf.hostname
        raise sqlmapConnectionException, errMsg

    if not suppressOutput:
        infoMsg = "testing connection to the target url"
        logger.info(infoMsg)

    try:
        page, _ = Request.queryPage(content=True)
        conf.seqMatcher.set_seq1(page)

    except sqlmapConnectionException, errMsg:
        errMsg = getUnicode(errMsg)
        raise sqlmapConnectionException, errMsg

    return True