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110 lines
4.1 KiB
Python
110 lines
4.1 KiB
Python
# Output backends for sigmac
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# Copyright 2018 SOC Prime
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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# You should have received a copy of the GNU Lesser General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import sigma
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from .base import SingleTextQueryBackend
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from .exceptions import PartialMatchError, FullMatchError
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class QualysBackend(SingleTextQueryBackend):
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"""Converts Sigma rule into Qualys saved search. Contributed by SOC Prime. https://socprime.com"""
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identifier = "qualys"
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active = True
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config_required = False
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default_config = ["sysmon", "qualys"]
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andToken = " and "
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orToken = " or "
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notToken = "not "
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subExpression = "(%s)"
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listExpression = "%s"
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listSeparator = " "
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valueExpression = "%s"
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nullExpression = "%s is null"
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notNullExpression = "not (%s is null)"
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mapExpression = "%s:`%s`"
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mapListsSpecialHandling = True
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PartialMatchFlag = False
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def __init__(self, *args, **kwargs):
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super().__init__(*args, **kwargs)
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fl = []
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for item in self.sigmaconfig.fieldmappings.values():
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if item.target_type == list:
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fl.extend(item.target)
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else:
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fl.append(item.target)
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self.allowedFieldsList = list(set(fl))
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def generateORNode(self, node):
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new_list = []
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for val in node:
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if type(val) == tuple and not(val[0] in self.allowedFieldsList):
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pass
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# self.PartialMatchFlag = True
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else:
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new_list.append(val)
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generated = [self.generateNode(val) for val in new_list]
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filtered = [g for g in generated if g is not None]
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return self.orToken.join(filtered)
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def generateANDNode(self, node):
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new_list = []
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for val in node:
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if type(val) == tuple and not(val[0] in self.allowedFieldsList):
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self.PartialMatchFlag = True
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else:
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new_list.append(val)
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generated = [self.generateNode(val) for val in new_list]
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filtered = [g for g in generated if g is not None]
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return self.andToken.join(filtered)
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def generateMapItemNode(self, node):
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key, value = node
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if self.mapListsSpecialHandling == False and type(value) in (str, int, list) or self.mapListsSpecialHandling == True and type(value) in (str, int):
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if key in self.allowedFieldsList:
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return self.mapExpression % (key, self.generateNode(value))
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else:
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return self.generateNode(value)
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elif type(value) == list:
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return self.generateMapItemListNode(key, value)
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else:
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raise TypeError("Backend does not support map values of type " + str(type(value)))
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def generateMapItemListNode(self, key, value):
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itemslist = []
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for item in value:
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if key in self.allowedFieldsList:
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itemslist.append('%s:`%s`' % (key, self.generateValueNode(item)))
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else:
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itemslist.append('%s' % (self.generateValueNode(item)))
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return "(" + (" or ".join(itemslist)) + ")"
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def generate(self, sigmaparser):
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"""Method is called for each sigma rule and receives the parsed rule (SigmaParser)"""
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all_keys = set()
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for parsed in sigmaparser.condparsed:
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query = self.generateQuery(parsed)
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if query == "()":
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self.PartialMatchFlag = None
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if self.PartialMatchFlag == True:
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raise PartialMatchError(query)
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elif self.PartialMatchFlag == None:
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raise FullMatchError(query)
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else:
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return query
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