Merge pull request #1620 from volatilityfoundation/issue_1474_orphan_…

…threads

Enforce kernel boundaries correctly. Fix bugs. Closes #1474

volatility3/framework/plugins/windows/modules.py

@@ -4,7 +4,7 @@
 import logging
 from typing import Generator, Iterable, List, Optional
 
-from volatility3.framework import constants, exceptions, interfaces, renderers
+from volatility3.framework import symbols, constants, exceptions, interfaces, renderers
 from volatility3.framework.configuration import requirements
 from volatility3.framework.renderers import format_hints
 from volatility3.framework.symbols import intermed
@@ -18,7 +18,7 @@ class Modules(interfaces.plugins.PluginInterface):
     """Lists the loaded kernel modules."""
 
     _required_framework_version = (2, 0, 0)
-    _version = (2, 0, 1)
+    _version = (2, 1, 0)
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
@@ -127,6 +127,32 @@ def _generator(self):
                 file_output,
             )
 
+    @classmethod
+    def get_kernel_space_start(cls, context, module_name: str) -> int:
+        """
+        Returns the starting address of the kernel address space
+
+        This method allows plugins that analyze kernel data structures to quickly detect
+        smeared or otherwise invalid data as many pointers must point into the kernel or
+        access during runtime would crash the system
+        """
+        module = context.modules[module_name]
+
+        if symbols.symbol_table_is_64bit(context, module.symbol_table_name):
+            object_type = "unsigned long long"
+        else:
+            object_type = "unsigned long"
+
+        range_start_offset = module.get_symbol("MmSystemRangeStart").address
+
+        kernel_space_start = module.object(
+            object_type=object_type, offset=range_start_offset
+        )
+
+        layer = context.layers[module.layer_name]
+
+        return kernel_space_start & layer.address_mask
+
     @classmethod
     def get_session_layers(
         cls,

volatility3/framework/plugins/windows/orphan_kernel_threads.py

@@ -5,9 +5,9 @@
 import logging
 from typing import List, Generator
 
-from volatility3.framework import interfaces, symbols
+from volatility3.framework import interfaces, exceptions
 from volatility3.framework.configuration import requirements
-from volatility3.plugins.windows import thrdscan, ssdt
+from volatility3.plugins.windows import thrdscan, ssdt, modules
 
 vollog = logging.getLogger(__name__)
 
@@ -37,6 +37,9 @@ def get_requirements(cls) -> List[interfaces.configuration.RequirementInterface]
             requirements.PluginRequirement(
                 name="ssdt", plugin=ssdt.SSDT, version=(1, 0, 0)
             ),
+            requirements.PluginRequirement(
+                name="modules", plugin=modules.Modules, version=(2, 1, 0)
+            ),
         ]
 
     @classmethod
@@ -56,39 +59,47 @@ def list_orphan_kernel_threads(
         """
         module = context.modules[module_name]
         layer_name = module.layer_name
-        symbol_table = module.symbol_table_name
+        symbol_table_name = module.symbol_table_name
 
         collection = ssdt.SSDT.build_module_collection(
-            context, layer_name, symbol_table
+            context, layer_name, symbol_table_name
         )
 
-        # FIXME - use a proper constant once established
-        # used to filter out smeared pointers
-        if symbols.symbol_table_is_64bit(context, symbol_table):
-            kernel_start = 0xFFFFF80000000000
-        else:
-            kernel_start = 0x80000000
+        kernel_space_start = modules.Modules.get_kernel_space_start(
+            context, module_name
+        )
 
         for thread in thrdscan.ThrdScan.scan_threads(context, module_name):
-            # we don't want smeared or terminated threads
+            # We don't want smeared or terminated threads
+            # So we access the owning process (which could also be terminated or smeared)
+            # Plus check the start address holding page
             try:
                 proc = thread.owning_process()
-            except AttributeError:
+                pid = proc.UniqueProcessId
+                ppid = proc.InheritedFromUniqueProcessId
+
+                thread_start = thread.StartAddress
+            except (AttributeError, exceptions.InvalidAddressException):
                 continue
 
             # we only care about kernel threads, 4 = System
             # previous methods for determining if a thread was a kernel thread
             # such as bit fields and flags are not stable in Win10+
             # so we check if the thread is from the kernel itself or one its child
             # kernel processes (MemCompression, Regsitry, ...)
-            if proc.UniqueProcessId != 4 and proc.InheritedFromUniqueProcessId != 4:
+            if pid != 4 and ppid != 4:
+                continue
+
+            # if the thread has an exit time or terminated (4) state, then skip it
+            if thread.ExitTime.QuadPart > 0 or thread.Tcb.State == 4:
                 continue
 
-            if thread.StartAddress < kernel_start:
+            # threads pointing into userland, which is from smeared or terminated threads
+            if thread_start < kernel_space_start:
                 continue
 
             module_symbols = list(
-                collection.get_module_symbols_by_absolute_location(thread.StartAddress)
+                collection.get_module_symbols_by_absolute_location(thread_start)
             )
 
             # alert on threads that do not map to a module