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# Detecting Bebloh(Shiotob, URLZone) 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 beblohscan.py volatility/plugins/malware
# 3. python vol.py beblohconfig -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
bebloh_sig = {
'namespace1' : 'rule Bebloh { \
strings: \
$crc32f = { b8 EE 56 0b ca } \
$dga = "qwertyuiopasdfghjklzxcvbnm123945678" \
$post1 = "&vcmd=" \
$post2 = "?tver=" \
condition: all of them}'
}
# RSA key header
RSA_HEADER = b"\x06\x02\x00\x00\x00\xa4\x00\x00\x52\x53\x41\x31\x00\x04\x00\x00"
# Config pattern
CONFIG_PATTERNS = [re.compile("\x83\x45\x08\x02\xe8(....)", re.DOTALL)]
class beblohConfig(taskmods.DllList):
"""Parse the Bebloh 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
def crc32(self, buf, value):
table = []
for i in range(256):
v = i
for j in range(8):
v = (0xEDB88320 ^ (v >> 1)) if(v & 1) == 1 else (v >> 1)
table.append(v)
for c in buf:
value = value ^ ord(c)
value = table[value & 0xFF] ^ (value >> 8)
return value
def sum_of_characters(self, domain):
return sum([ord(d) for d in domain[:-3]])
def get_next_domain(self, domain, xor):
qwerty = "qwertyuiopasdfghjklzxcvbnm123945678"
sof = self.sum_of_characters(domain) ^ xor
ascii_codes = [ord(d) for d in domain] + 100 * [0]
old_hostname_length = len(domain) - 4
for i in range(0, 66):
for j in range(0, 66):
edi = j + i
if edi < 65:
p = (old_hostname_length * ascii_codes[j])
cl = p ^ ascii_codes[edi] ^ sof
ascii_codes[edi] = cl & 0xFF
"""
calculate the new hostname length
max: 255/16 = 15
min: 10
"""
cx = ((ascii_codes[2] * old_hostname_length) ^ ascii_codes[0]) & 0xFF
hostname_length = int(cx / 16) # at most 15
if hostname_length < 10:
hostname_length = old_hostname_length
"""
generate hostname
"""
for i in range(hostname_length):
index = int(ascii_codes[i] / 8) # max 31 --> last 3 chars of qwerty unreachable
bl = ord(qwerty[index])
ascii_codes[i] = bl
hostname = ''.join([chr(a) for a in ascii_codes[:hostname_length]])
"""
append .net or .com (alternating)
"""
tld = '.com' if domain.endswith('.net') else '.net'
domain = hostname + tld
return domain
def parse_config(self, data, base, rsa_key, dga_key):
p_data = OrderedDict()
p_data["RSA key"] = rsa_key.encode("hex")
p_data["Sleep count"] = unpack_from("<I", data, base + 5)[0]
p_data["Seed URL"] = data[base + 9:base + 0x29].replace("\0", "")
p_data["Sleep time"] = unpack_from("<I", data, base + 0xf9)[0]
p_data["Botid"] = data[base + 0xfd:base + 0x10f].replace("\0", "")
p_data["Registry subkey"] = data[base + 0x136:base + 0x160].replace("\0", "")
site_check_flag = unpack_from("<I", data, base + 0xf9)[0]
if site_check_flag != 0:
site_check = "Enable"
else:
site_check = "Disable"
p_data["Network Chack"] = site_check
p_data["Botnet"] = data[base + 0x178:base + 0x188].replace("\0", "")
p_data["Registry key"] = data[base + 0x188:base + 0x194].replace("\0", "")
domain = data[base + 9:base + 0x29].split("/")[0]
for i in range(51):
p_data["DGA " + str(i)] = domain
domain = self.get_next_domain(domain, dga_key)
return p_data
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=bebloh_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()
data = proc_addr_space.zread(vad_base_addr, end - vad_base_addr)
config_data = []
rsa_key_index = data.find(RSA_HEADER)
rsa_key = data[rsa_key_index:rsa_key_index + 0x94]
dga_key = self.crc32(rsa_key, 0xCA0B56EE)
for pattern in CONFIG_PATTERNS:
offset = re.search(pattern, data).start()
while not (data[offset] == "\xBA" or data[offset] == "\xB8"):
offset += 1
(config_addr, ) = unpack("=I", data[offset + 1:offset + 5])
config_addr -= vad_base_addr
config_data.append(self.parse_config(data, config_addr, rsa_key, dga_key))
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:<16}: {1}\n".format(id, param))
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