Add in Dosfuscation Signature

modules/signatures/windows/commandline_anomaly.py

@@ -0,0 +1,112 @@
+# Copyright (C) 2018 Kevin Ross
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from lib.cuckoo.common.abstracts import Signature
+
+class CmdlineCompsecEvasion(Signature):
+    name = "cmdline_comspec_evasion"
+    description = "Uses the %COMSPEC% environment variable to access the command line interpreter to evade detection"
+    severity = 3
+    categories = ["commands"]
+    authors = ["Kevin Ross"]
+    minimum = "2.0"
+    references = ["www.fireeye.com/content/dam/fireeye-www/blog/pdfs/dosfuscation-report.pdf"]
+
+    def on_complete(self):
+        for cmdline in self.get_command_lines():
+            if "%comspec" in cmdline.lower():
+                self.mark_ioc("cmdline", cmdline)
+
+        return self.has_marks()
+
+class CmdlineChracterObfsucation(Signature):
+    name = "cmdline_chracter_obfuscation"
+    description = "Appears to use character obfuscation in a command line"
+    severity = 3
+    categories = ["commands"]
+    authors = ["Kevin Ross"]
+    minimum = "2.0"
+    references = ["www.fireeye.com/content/dam/fireeye-www/blog/pdfs/dosfuscation-report.pdf"]
+
+    def on_complete(self):
+        for cmdline in self.get_command_lines():
+            if "cmd" in cmdline.lower() and (cmdline.count("^") > 3 or cmdline.count("&") > 6 or cmdline.count("+") > 4 or cmdline.count("\"") > 8 or cmdline.count(";") > 6):
+                self.mark_ioc("cmdline", cmdline)
+
+        return self.has_marks()
+
+class CmdlineConcatenationObfsucation(Signature):
+    name = "cmdline_concatenation_obfuscation"
+    description = "Appears to use adjacent environment variables for concatenation reassembly obfuscation in a command line"
+    severity = 3
+    categories = ["commands"]
+    authors = ["Kevin Ross"]
+    minimum = "2.0"
+    references = ["www.fireeye.com/content/dam/fireeye-www/blog/pdfs/dosfuscation-report.pdf"]
+
+    def on_complete(self):
+        for cmdline in self.get_command_lines():
+            if "cmd" in cmdline.lower() and re.search('(%[^%]+%){4}', cmdline):
+                self.mark_ioc("cmdline", cmdline)
+
+        return self.has_marks()
+
+class CmdlineSetObfsucation(Signature):
+    name = "cmdline_set_obfuscation"
+    description = "Appears to use set to define variables in a command line likely for obfuscation"
+    severity = 3
+    categories = ["commands"]
+    authors = ["Kevin Ross"]
+    minimum = "2.0"
+    references = ["www.fireeye.com/content/dam/fireeye-www/blog/pdfs/dosfuscation-report.pdf"]
+
+    def on_complete(self):
+        for cmdline in self.get_command_lines():
+            if "cmd" in cmdline.lower() and cmdline.lower().count("set ") > 2:
+                self.mark_ioc("cmdline", cmdline)
+
+        return self.has_marks()
+
+class CmdlineSetCallObfsucation(Signature):
+    name = "cmdline_setcall_obfuscation"
+    description = "Appears to use set and call to define a variable in a command line likely for obfuscation"
+    severity = 3
+    categories = ["commands"]
+    authors = ["Kevin Ross"]
+    minimum = "2.0"
+    references = ["www.fireeye.com/content/dam/fireeye-www/blog/pdfs/dosfuscation-report.pdf"]
+
+    def on_complete(self):
+        for cmdline in self.get_command_lines():
+            if "cmd" in cmdline.lower() and "set " in cmdline.lower() and "call " in cmdline.lower():
+                self.mark_ioc("cmdline", cmdline)
+
+        return self.has_marks()
+
+class CmdlineSetForLoopObfsucation(Signature):
+    name = "cmdline_set_forloop_obfuscation"
+    description = "Appears to use a for loop in a command line likely for obfuscation"
+    severity = 3
+    categories = ["commands"]
+    authors = ["Kevin Ross"]
+    minimum = "2.0"
+    references = ["www.fireeye.com/content/dam/fireeye-www/blog/pdfs/dosfuscation-report.pdf"]
+
+    def on_complete(self):
+        for cmdline in self.get_command_lines():
+            if "cmd" in cmdline.lower() and "set " in cmdline.lower() and "for " in cmdline.lower():
+                self.mark_ioc("cmdline", cmdline)
+
+        return self.has_marks()