Added dns tampering, tamper tests

4 years ago · 37929a8e27
parent 7495b334bb
commit 37929a8e27
2 changed files with 410 additions and 9 deletions
--- a/actions/tamper.py
+++ b/actions/tamper.py
@ -2,17 +2,25 @@
 TamperAction

 One of the four packet-level primitives supported by Geneva. Responsible for any packet-level
-modifications (particularly header modifications). It supports replace and corrupt mode -
-in replace mode, it changes a packet field to a fixed value; in corrupt mode, it changes a packet
-field to a randomly generated value each time it is run.
+modifications (particularly header modifications). It supports the following primitives:
+ - no operation: it returns the packet given
+ - replace: it changes a packet field to a fixed value
+ - corrupt: it changes a packet field to a randomly generated value each time it is run
+ - add: adds a given value to the value in a field
+ - compress: performs DNS decompression on the packet (if applicable)
 """

 from actions.action import Action
 import actions.utils
+from actions.layer import DNSLayer

 import random


+# All supported tamper primitives
+SUPPORTED_PRIMITIVES = ["corrupt", "replace", "add", "compress"]
+
+
 class TamperAction(Action):
    """
    Defines the TamperAction for Geneva.
@ -23,10 +31,7 @@ class TamperAction(Action):
        self.tamper_value = tamper_value
        self.tamper_proto = actions.utils.string_to_protocol(tamper_proto)
        self.tamper_proto_str = tamper_proto
-
        self.tamper_type = tamper_type
-        if not self.tamper_type:
-            self.tamper_type = random.choice(["corrupt", "replace"])

    def tamper(self, packet, logger):
        """
@ -41,8 +46,19 @@ class TamperAction(Action):

        new_value = self.tamper_value
        # If corrupting the packet field, generate a value for it
-        if self.tamper_type == "corrupt":
-            new_value = packet.gen(self.tamper_proto_str, self.field)
+        try:
+            if self.tamper_type == "corrupt":
+                new_value = packet.gen(self.tamper_proto_str, self.field)
+            elif self.tamper_type == "add":
+                new_value = int(self.tamper_value) + int(old_value)
+            elif self.tamper_type == "compress":
+                return packet.dns_decompress(logger)
+        except NotImplementedError:
+            # If a primitive does not support the type of packet given
+            return packet
+        except Exception:
+            # If an unexpected error has occurred
+            return packet

        logger.debug("  - Tampering %s field `%s` (%s) by %s (to %s)" %
                     (self.tamper_proto_str, self.field, str(old_value), self.tamper_type, str(new_value)))
@ -67,8 +83,10 @@ class TamperAction(Action):
        s = Action.__str__(self)
        if self.tamper_type == "corrupt":
            s += "{%s:%s:%s}" % (self.tamper_proto_str, self.field, self.tamper_type)
-        elif self.tamper_type in ["replace"]:
+        elif self.tamper_type in ["replace", "add"]:
            s += "{%s:%s:%s:%s}" % (self.tamper_proto_str, self.field, self.tamper_type, self.tamper_value)
+        elif self.tamper_type == "compress":
+            s += "{%s:%s:compress}" % ("DNS", "qd", )

        return s

--- a/tests/test_tamper.py
+++ b/tests/test_tamper.py
@ -0,0 +1,383 @@
+import copy
+import logging
+import sys
+import pytest
+import random
+# Include the root of the project
+sys.path.append("..")
+
+import actions.strategy
+import actions.packet
+import actions.utils
+import actions.tamper
+import actions.layer
+
+from scapy.all import IP, TCP, UDP, DNS, DNSQR, sr1
+
+
+logger = logging.getLogger("test")
+
+
+def test_tamper():
+    """
+    Tests tampering with replace
+    """
+    packet = actions.packet.Packet(IP(src="127.0.0.1", dst="127.0.0.1")/TCP(sport=2222, dport=3333, seq=100, ack=100, flags="S"))
+    original = copy.deepcopy(packet)
+    tamper = actions.tamper.TamperAction(None, field="flags", tamper_type="replace", tamper_value="R")
+    lpacket, rpacket = tamper.run(packet, logger)
+    assert not rpacket, "Tamper must not return right child"
+    assert lpacket, "Tamper must give a left child"
+    assert id(lpacket) == id(packet), "Tamper must edit in place"
+
+    # Confirm tamper replaced the field it was supposed to
+    assert packet[TCP].flags == "R", "Tamper did not replace flags."
+    new_value = packet[TCP].flags
+
+    # Must run this check repeatedly - if a scapy fuzz-ed value is not properly
+    # ._fix()-ed, it will return different values each time it's requested
+    for _ in range(0, 5):
+        assert packet[TCP].flags == new_value, "Replaced value is not stable"
+
+    # Confirm tamper didn't corrupt anything else in the TCP header
+    assert confirm_unchanged(packet, original, TCP, ["flags"])
+
+    # Confirm tamper didn't corrupt anything in the IP header
+    assert confirm_unchanged(packet, original, IP, [])
+
+
+def test_tamper_ip():
+    """
+    Tests tampering with IP
+    """
+    packet = actions.packet.Packet(IP(src='127.0.0.1', dst='127.0.0.1')/TCP(sport=2222, dport=3333, seq=100, ack=100, flags="S"))
+    original = copy.deepcopy(packet)
+    tamper = actions.tamper.TamperAction(None, field="src", tamper_type="replace", tamper_value="192.168.1.1", tamper_proto="IP")
+    lpacket, rpacket = tamper.run(packet, logger)
+    assert not rpacket, "Tamper must not return right child"
+    assert lpacket, "Tamper must give a left child"
+    assert id(lpacket) == id(packet), "Tamper must edit in place"
+
+    # Confirm tamper replaced the field it was supposed to
+    assert packet[IP].src == "192.168.1.1", "Tamper did not replace flags."
+
+    # Confirm tamper didn't corrupt anything in the TCP header
+    assert confirm_unchanged(packet, original, TCP, [])
+
+    # Confirm tamper didn't corrupt anything else in the IP header
+    assert confirm_unchanged(packet, original, IP, ["src"])
+
+
+def test_tamper_udp():
+    """
+    Tests tampering with UDP
+    """
+    packet = actions.packet.Packet(IP(src='127.0.0.1', dst='127.0.0.1')/UDP(sport=2222, dport=53))
+    original = copy.deepcopy(packet)
+    tamper = actions.tamper.TamperAction(None, field="chksum", tamper_type="replace", tamper_value=4444, tamper_proto="UDP")
+    lpacket, rpacket = tamper.run(packet, logger)
+    assert not rpacket, "Tamper must not return right child"
+    assert lpacket, "Tamper must give a left child"
+    assert id(lpacket) == id(packet), "Tamper must edit in place"
+
+    # Confirm tamper replaced the field it was supposed to
+    assert packet[UDP].chksum == 4444, "Tamper did not replace flags."
+
+    # Confirm tamper didn't corrupt anything in the TCP header
+    assert confirm_unchanged(packet, original, UDP, ["chksum"])
+
+    # Confirm tamper didn't corrupt anything else in the IP header
+    assert confirm_unchanged(packet, original, IP, [])
+
+
+def test_tamper_ip_ident():
+    """
+    Tests tampering with IP and that the checksum is correctly changed
+    """
+
+    packet = actions.packet.Packet(IP(src='127.0.0.1', dst='127.0.0.1')/TCP(sport=2222, dport=3333, seq=100, ack=100, flags="S"))
+    original = copy.deepcopy(packet)
+    tamper = actions.tamper.TamperAction(None, field='id', tamper_type='replace', tamper_value=3333, tamper_proto="IP")
+    lpacket, rpacket = tamper.run(packet, logger)
+    assert not rpacket, "Tamper must not return right child"
+    assert lpacket, "Tamper must give a left child"
+    assert id(lpacket) == id(packet), "Tamper must edit in place"
+
+    # Confirm tamper replaced the field it was supposed to
+    assert packet[IP].id == 3333, "Tamper did not replace flags."
+
+    # Confirm tamper didn't corrupt anything in the TCP header
+    assert confirm_unchanged(packet, original, TCP, [])
+
+    # Confirm tamper didn't corrupt anything else in the IP header
+    assert confirm_unchanged(packet, original, IP, ["id"])
+
+
+def confirm_unchanged(packet, original, protocol, changed):
+    """
+    Checks that no other field besides the given array of changed fields
+    are different between these two packets.
+    """
+    for header in packet.layers:
+        if packet.layers[header].protocol != protocol:
+            continue
+        for field in packet.layers[header].fields:
+            # Skip checking the field we just changed
+            if field in changed or field == "load":
+                continue
+            assert packet.get(protocol.__name__, field) == original.get(protocol.__name__, field), "Tamper changed %s field %s." % (str(protocol), field)
+    return True
+
+
+def test_parse_parameters():
+    """
+    Tests that tamper properly rejects malformed tamper actions
+    """
+    with pytest.raises(Exception):
+        actions.tamper.TamperAction().parse("this:has:too:many:parameters", logger)
+    with pytest.raises(Exception):
+        actions.tamper.TamperAction().parse("not:enough", logger)
+
+
+
+def test_corrupt():
+    """
+    Tests the tamper 'corrupt' primitive.
+    """
+    tamper = actions.tamper.TamperAction(None, field="flags", tamper_type="corrupt", tamper_value="R")
+    assert tamper.field == "flags", "Tamper action changed fields."
+    assert tamper.tamper_type == "corrupt", "Tamper action changed types."
+    assert str(tamper) == "tamper{TCP:flags:corrupt}", "Tamper returned incorrect string representation: %s" % str(tamper)
+
+    packet = actions.packet.Packet(IP(src="127.0.0.1", dst="127.0.0.1")/TCP(sport=2222, dport=3333, seq=100, ack=100, flags="S"))
+    original = copy.deepcopy(packet)
+    tamper.tamper(packet, logger)
+
+    new_value = packet[TCP].flags
+
+    # Must run this check repeatedly - if a scapy fuzz-ed value is not properly
+    # ._fix()-ed, it will return different values each time it's requested
+    for _ in range(0, 5):
+        assert packet[TCP].flags == new_value, "Corrupted value is not stable"
+
+    # Confirm tamper didn't corrupt anything else in the TCP header
+    assert confirm_unchanged(packet, original, TCP, ["flags"])
+
+    # Confirm tamper didn't corrupt anything else in the IP header
+    assert confirm_unchanged(packet, original, IP, [])
+
+
+def test_add():
+    """
+    Tests the tamper 'add' primitive.
+    """
+    tamper = actions.tamper.TamperAction(None, field="seq", tamper_type="add", tamper_value=10)
+    assert tamper.field == "seq", "Tamper action changed fields."
+    assert tamper.tamper_type == "add", "Tamper action changed types."
+    assert str(tamper) == "tamper{TCP:seq:add:10}", "Tamper returned incorrect string representation: %s" % str(tamper)
+
+    packet = actions.packet.Packet(IP(src="127.0.0.1", dst="127.0.0.1")/TCP(sport=2222, dport=3333, seq=100, ack=100, flags="S"))
+    original = copy.deepcopy(packet)
+    tamper.tamper(packet, logger)
+
+    new_value = packet[TCP].seq
+    assert new_value == 110, "Tamper did not add"
+
+    # Must run this check repeatedly - if a scapy fuzz-ed value is not properly
+    # ._fix()-ed, it will return different values each time it's requested
+    for _ in range(0, 5):
+        assert packet[TCP].seq == new_value, "Corrupted value is not stable"
+
+    # Confirm tamper didn't corrupt anything else in the TCP header
+    assert confirm_unchanged(packet, original, TCP, ["seq"])
+
+    # Confirm tamper didn't corrupt anything else in the IP header
+    assert confirm_unchanged(packet, original, IP, [])
+
+
+def test_decompress():
+    """
+    Tests the tamper 'decompress' primitive.
+    """
+    tamper = actions.tamper.TamperAction(None, field="qd", tamper_type="compress", tamper_value=10, tamper_proto="DNS")
+    assert tamper.field == "qd", "Tamper action changed fields."
+    assert tamper.tamper_type == "compress", "Tamper action changed types."
+    assert str(tamper) == "tamper{DNS:qd:compress}", "Tamper returned incorrect string representation: %s" % str(tamper)
+
+    packet = actions.packet.Packet(IP(dst="8.8.8.8")/UDP(dport=53)/DNS(qd=DNSQR(qname="minghui.ca.")))
+    original = packet.copy()
+    tamper.tamper(packet, logger)
+    assert bytes(packet["DNS"]) == b'\x00\x00\x01\x00\x00\x02\x00\x00\x00\x00\x00\x00\x07minghui\xc0\x1a\x00\x01\x00\x01\x02ca\x00\x00\x01\x00\x01'
+    resp = sr1(packet.packet)
+    assert resp["DNS"]
+    assert resp["DNS"].rcode != 1
+    assert resp["DNSQR"]
+    assert resp["DNSRR"].rdata
+    assert confirm_unchanged(packet, original, IP, ["len"])
+    print(resp.summary())
+
+    packet = actions.packet.Packet(IP(dst="8.8.8.8")/UDP(dport=53)/DNS(qd=DNSQR(qname="maps.google.com")))
+    original = packet.copy()
+    tamper.tamper(packet, logger)
+    assert bytes(packet["DNS"]) == b'\x00\x00\x01\x00\x00\x02\x00\x00\x00\x00\x00\x00\x04maps\xc0\x17\x00\x01\x00\x01\x06google\x03com\x00\x00\x01\x00\x01'
+    resp = sr1(packet.packet)
+    assert resp["DNS"]
+    assert resp["DNS"].rcode != 1
+    assert resp["DNSQR"]
+    assert resp["DNSRR"].rdata
+    assert confirm_unchanged(packet, original, IP, ["len"])
+    print(resp.summary())
+
+    # Confirm this is a NOP on normal packets
+    packet = actions.packet.Packet(IP()/UDP())
+    original = packet.copy()
+    tamper.tamper(packet, logger)
+    assert packet.packet.summary() == original.packet.summary()
+
+    # Confirm tamper didn't corrupt anything else in the TCP header
+    assert confirm_unchanged(packet, original, UDP, [])
+
+    # Confirm tamper didn't corrupt anything else in the IP header
+    assert confirm_unchanged(packet, original, IP, [])
+
+
+def test_corrupt_chksum():
+    """
+    Tests the tamper 'replace' primitive.
+    """
+    tamper = actions.tamper.TamperAction(None, field="chksum", tamper_type="corrupt", tamper_value="R")
+    assert tamper.field == "chksum", "Tamper action changed checksum."
+    assert tamper.tamper_type == "corrupt", "Tamper action changed types."
+    assert str(tamper) == "tamper{TCP:chksum:corrupt}", "Tamper returned incorrect string representation: %s" % str(tamper)
+
+    packet = actions.packet.Packet(IP(src="127.0.0.1", dst="127.0.0.1")/TCP(sport=2222, dport=3333, seq=100, ack=100, flags="S"))
+    original = copy.deepcopy(packet)
+    tamper.tamper(packet, logger)
+
+    # Confirm tamper actually corrupted the checksum
+    assert packet[TCP].chksum != 0
+    new_value = packet[TCP].chksum
+
+    # Must run this check repeatedly - if a scapy fuzz-ed value is not properly
+    # ._fix()-ed, it will return different values each time it's requested
+    for _ in range(0, 5):
+        assert packet[TCP].chksum == new_value, "Corrupted value is not stable"
+
+    # Confirm tamper didn't corrupt anything else in the TCP header
+    assert confirm_unchanged(packet, original, TCP, ["chksum"])
+
+    # Confirm tamper didn't corrupt anything else in the IP header
+    assert confirm_unchanged(packet, original, IP, [])
+
+
+def test_corrupt_dataofs():
+    """
+    Tests the tamper 'replace' primitive.
+    """
+    packet = actions.packet.Packet(IP(src="127.0.0.1", dst="127.0.0.1")/TCP(sport=2222, dport=3333, seq=100, ack=100, flags="S", dataofs="6L"))
+    original = copy.deepcopy(packet)
+    tamper = actions.tamper.TamperAction(None, field="dataofs", tamper_type="corrupt")
+
+    tamper.tamper(packet, logger)
+
+    # Confirm tamper actually corrupted the checksum
+    assert packet[TCP].dataofs != "0"
+    new_value = packet[TCP].dataofs
+
+    # Must run this check repeatedly - if a scapy fuzz-ed value is not properly
+    # ._fix()-ed, it will return different values each time it's requested
+    for _ in range(0, 5):
+        assert packet[TCP].dataofs == new_value, "Corrupted value is not stable"
+
+    # Confirm tamper didn't corrupt anything else in the TCP header
+    assert confirm_unchanged(packet, original, TCP, ["dataofs"])
+
+    # Confirm tamper didn't corrupt anything in the IP header
+    assert confirm_unchanged(packet, original, IP, [])
+
+
+def test_replace():
+    """
+    Tests the tamper 'replace' primitive.
+    """
+    tamper = actions.tamper.TamperAction(None, field="flags", tamper_type="replace", tamper_value="R")
+
+    assert tamper.field == "flags", "Tamper action changed fields."
+    assert tamper.tamper_type == "replace", "Tamper action changed types."
+
+    packet = actions.packet.Packet(IP(src="127.0.0.1", dst="127.0.0.1")/TCP(sport=2222, dport=3333, seq=100, ack=100, flags="S"))
+    original = copy.deepcopy(packet)
+    tamper.tamper(packet, logger)
+
+    # Confirm tamper replaced the field it was supposed to
+    assert packet[TCP].flags == "R", "Tamper did not replace flags."
+    # Confirm tamper didn't replace anything else in the TCP header
+    assert confirm_unchanged(packet, original, TCP, ["flags"])
+
+    # Confirm tamper didn't replace anything else in the IP header
+    assert confirm_unchanged(packet, original, IP, [])
+
+    # chksums must be handled specially by tamper, so run a second check on this value
+    tamper.field = "chksum"
+    tamper.tamper_value = 0x4444
+    original = copy.deepcopy(packet)
+    tamper.tamper(packet, logger)
+    assert packet[TCP].chksum == 0x4444, "Tamper failed to change chksum."
+    # Confirm tamper didn't replace anything else in the TCP header
+    assert confirm_unchanged(packet, original, TCP, ["chksum"])
+    # Confirm tamper didn't replace anything else in the IP header
+    assert confirm_unchanged(packet, original, IP, [])
+
+
+def test_parse_flags():
+    """
+    Tests the tamper 'replace' primitive.
+    """
+    tamper = actions.tamper.TamperAction(None, field="flags", tamper_type="replace", tamper_value="FRAPUN")
+    assert tamper.field == "flags", "Tamper action changed checksum."
+    assert tamper.tamper_type == "replace", "Tamper action changed types."
+    assert str(tamper) == "tamper{TCP:flags:replace:FRAPUN}", "Tamper returned incorrect string representation: %s" % str(tamper)
+
+    packet = actions.packet.Packet(IP(src="127.0.0.1", dst="127.0.0.1")/TCP(sport=2222, dport=3333, seq=100, ack=100, flags="S"))
+    tamper.tamper(packet, logger)
+    assert packet[TCP].flags == "FRAPUN", "Tamper failed to change flags."
+
+
+@pytest.mark.parametrize("test_type", ["parsed", "direct"])
+@pytest.mark.parametrize("value", ["EOL", "NOP", "Timestamp", "MSS", "WScale", "SAckOK", "SAck", "Timestamp", "AltChkSum", "AltChkSumOpt", "UTO"])
+def test_options(value, test_type):
+    """
+    Tests tampering options
+    """
+    if test_type == "direct":
+        tamper = actions.tamper.TamperAction(None, field="options-%s" % value.lower(), tamper_type="corrupt", tamper_value=bytes([12]))
+    else:
+        tamper = actions.tamper.TamperAction(None)
+        assert tamper.parse("TCP:options-%s:corrupt" % value.lower(), logger)
+
+    packet = actions.packet.Packet(IP(src="127.0.0.1", dst="127.0.0.1")/TCP(sport=2222, dport=3333, seq=100, ack=100, flags="S"))
+    tamper.run(packet, logger)
+    opts_dict_lookup = value.lower().replace(" ", "_")
+
+    for optname, optval in packet["TCP"].options:
+        if optname == value:
+            break
+        elif optname == actions.layer.TCPLayer.options_names[opts_dict_lookup]:
+            break
+    else:
+        pytest.fail("Failed to find %s in options" % value)
+    assert len(packet["TCP"].options) == 1
+    raw_p = bytes(packet)
+    assert raw_p, "options broke scapy bytes"
+    p2 = actions.packet.Packet(IP(bytes(raw_p)))
+    assert p2.haslayer("IP")
+    assert p2.haslayer("TCP")
+    # EOLs might be added for padding, so just check >= 1
+    assert len(p2["TCP"].options) >= 1
+    for optname, optval in p2["TCP"].options:
+        if optname == value:
+            break
+        elif optname == actions.layer.TCPLayer.options_names[opts_dict_lookup]:
+            break
+    else:
+        pytest.fail("Failed to find %s in options" % value)