File size: 6,427 Bytes
8377638 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 |
# Detecting SmokeLoader for Volatility
#
# LICENSE
# Please refer to the LICENSE.txt in the https://github.com/JPCERTCC/MalConfScan/
#
# How to use:
# 1. cd "Volatility Folder"
# 2. mv smokeloaderscan.py volatility/plugins/malware
# 3. python vol.py smokeloaderconfig -f images.mem --profile=Win7SP1x64
import volatility.plugins.taskmods as taskmods
import volatility.win32.tasks as tasks
import volatility.utils as utils
import volatility.debug as debug
import volatility.plugins.malware.malfind as malfind
import re
from struct import unpack, unpack_from
from collections import OrderedDict
try:
import yara
has_yara = True
except ImportError:
has_yara = False
smokeloader_sig = {
'namespace1' : 'rule SmokeLoader { \
strings: \
$a1 = { B8 25 30 38 58 } \
$b1 = { 81 3D ?? ?? ?? ?? 25 00 41 00 } \
$c1 = { C7 ?? ?? ?? 25 73 25 73 } \
condition: $a1 and $b1 and $c1}'
}
# Config pattern
CONFIG_PATTERNS = [re.compile("\x68\x58\x02\x00\x00\xFF(.....)\x4E\x75\xF2\x8B", re.DOTALL)]
STRINGS_PATTERNS = [re.compile("\x57\xBB(....)\x8B(.)\x8B(.)", re.DOTALL)]
class smokeloaderConfig(taskmods.DllList):
"""Parse the SmokeLoader configuration"""
@staticmethod
def is_valid_profile(profile):
return (profile.metadata.get('os', 'unknown') == 'windows'), profile.metadata.get('memory_model', '32bit')
def get_vad_base(self, task, address):
for vad in task.VadRoot.traverse():
if address >= vad.Start and address < vad.End:
return vad.Start, vad.End
return None
# RC4
def rc4(self, data, key):
x = 0
box = range(256)
for i in range(256):
x = (x + box[i] + ord(key[i % len(key)])) % 256
box[i], box[x] = box[x], box[i]
x = 0
y = 0
out = []
for char in data:
x = (x + 1) % 256
y = (y + box[x]) % 256
box[x], box[y] = box[y], box[x]
out.append(chr(ord(char) ^ box[(box[x] + box[y]) % 256]))
return ''.join(out)
def decode(self, data, keydata):
url = []
key = 0xff
for i in range(0, 4):
key = key ^ (keydata >> (i * 8) & 0xff)
for y in data:
url.append(chr(ord(y) ^ key))
return "".join(url)
def calculate(self):
if not has_yara:
debug.error("Yara must be installed for this plugin")
addr_space = utils.load_as(self._config)
os, memory_model = self.is_valid_profile(addr_space.profile)
if not os:
debug.error("This command does not support the selected profile.")
rules = yara.compile(sources=smokeloader_sig)
for task in self.filter_tasks(tasks.pslist(addr_space)):
scanner = malfind.VadYaraScanner(task=task, rules=rules)
for hit, address in scanner.scan():
vad_base_addr, end = self.get_vad_base(task, address)
proc_addr_space = task.get_process_address_space()
dll_data = proc_addr_space.zread(vad_base_addr, end - vad_base_addr)
config_data = []
mz_magic = unpack_from("=2s", dll_data, 0x0)[0]
nt_magic = unpack_from("<H", dll_data, 0x3c)[0]
if mz_magic == "\x00\x00":
dll_data = "\x4d\x5a" + dll_data[2:]
dll_data = dll_data[:nt_magic] + "\x50\x45" + dll_data[nt_magic + 2:]
p_data = OrderedDict()
url_base = []
for pattern in CONFIG_PATTERNS:
mc = re.search(pattern, dll_data)
if mc:
offset = mc.end() + 1
while dll_data[offset] != "\x8B":
offset += 1
config_rva = unpack("=I", dll_data[offset + 3:offset + 7])[0] - vad_base_addr
d = 0
while dll_data[config_rva + d:config_rva + d + 4] != "\x00\x00\x00\x00":
url_base.append(unpack("=I", dll_data[config_rva + d:config_rva + d + 4])[0])
d += 4
i = 1
for base in url_base:
base -= vad_base_addr
size = ord(dll_data[base])
key = unpack("=I", dll_data[base + size + 1:base + size + 5])[0]
enc_data = dll_data[base + 1:base + size + 1]
url = self.decode(enc_data, key)
p_data["Static URL " + str(i)] = url
i += 1
for pattern in STRINGS_PATTERNS:
mc = re.search(pattern, dll_data)
if mc:
offset = mc.start() + 2
config_rva = unpack("=I", dll_data[offset:offset + 4])[0] - vad_base_addr
key = dll_data[config_rva - 4:config_rva]
enc = []
while dll_data[config_rva:config_rva + 2] != "\x00\x00":
enc.append(dll_data[config_rva])
config_rva += 1
enc_strings = "".join(enc)
x = 0
i = 1
while x < len(enc_strings):
size = ord(enc_strings[x])
strings = self.rc4(enc_strings[x + 1:x + size + 1], key)
x = x + size + 1
p_data["Encoded string " + str(i)] = strings
i += 1
config_data.append(p_data)
yield task, vad_base_addr, end, hit, memory_model, config_data
break
def render_text(self, outfd, data):
delim = '-' * 70
for task, start, end, malname, memory_model, config_data in data:
outfd.write("{0}\n".format(delim))
outfd.write("Process: {0} ({1})\n\n".format(task.ImageFileName, task.UniqueProcessId))
outfd.write("[Config Info]\n")
for p_data in config_data:
for id, param in p_data.items():
outfd.write("{0:<18}: {1}\n".format(id, param))
|