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# Detecting Wellmess 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 wellmessscan.py volatility/plugins/malware
# 3. python vol.py wellmessconfig -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
import pefile
from struct import unpack, unpack_from
from collections import OrderedDict
try:
import yara
has_yara = True
except ImportError:
has_yara = False
wellmess_sig = {
'namespace1' : 'rule Wellmess { \
strings: \
$botlib1 = "botlib.wellMess" ascii\
$botlib2 = "botlib.Command" ascii\
$botlib3 = "botlib.Download" ascii\
$botlib4 = "botlib.AES_Encrypt" ascii\
$dotnet1 = "WellMess" ascii\
$dotnet2 = "<;head;><;title;>" ascii wide\
$dotnet3 = "<;title;><;service;>" ascii wide\
$dotnet4 = "AES_Encrypt" ascii\
condition: (uint16(0) == 0x5A4D) and (all of ($botlib*) or all of ($dotnet*))}'
}
# Config pattern
CONFIG_PATTERNS = [re.compile("\x00(.)\x00\x00\x00\x8B\x05...\x00\x85\xC0\x0F\x85..\x00\x00\x8D\x05(....)\x89\x05...\x00\xC7\x05", re.DOTALL),
re.compile("\x00(.)\x00\x00\x00\x8B\x05...\x00\x85\xC0\x0F\x85..\x00\x00\x48\x8D\x05(....)\x48\x89\x05...\x00\x48\xC7\x05", re.DOTALL)]
CONFIG_PATTERNS_DOTNET = [re.compile("\x00\x0B\x61\x00\x3A\x00\x31\x00\x5F\x00\x30\x00\x00\x0B\x61\x00\x3A\x00\x31\x00\x5F\x00\x31\x00\x00", re.DOTALL)]
class wellmessConfig(taskmods.DllList):
"""Parse the Wellmess 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 parse_config(self, config):
p_data = OrderedDict()
for i, d in enumerate(config):
p_data["conf " + str(i)] = d
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=wellmess_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)
pe = pefile.PE(data=data)
config_data = []
configs = []
for pattern in CONFIG_PATTERNS:
mc = list(re.finditer(pattern, data))
if mc:
for m in mc:
hit_adderss = m.span()
config_rva = unpack("=I", m.groups()[1])[0]
if pe.FILE_HEADER.Machine == 0x14C: # for 32bit
config_offset = config_rva - pe.NT_HEADERS.OPTIONAL_HEADER.ImageBase
#config_offset = pe.get_physical_by_rva(config_rva - pe.NT_HEADERS.OPTIONAL_HEADER.ImageBase) + 0x1000
else: # for 64bit
config_offset = config_rva + hit_adderss[0] + 26
configs.append(data[config_offset:config_offset + ord(m.groups()[0])])
for pattern in CONFIG_PATTERNS_DOTNET:
mc = re.search(pattern, data)
if mc:
offset = mc.end()
for i in range(6):
strings = []
string_len = ord(data[offset])
if ord(data[offset]) == 0x80 or ord(data[offset]) == 0x83:
string_len = ord(data[offset + 1]) + ((ord(data[offset]) - 0x80) * 256)
offset += 1
offset += 1
for i in range(string_len):
if data[offset + i] != "\x00":
strings.append(data[offset + i])
if string_len != 1:
configs.append("".join(strings))
offset = offset + string_len
config_data.append(self.parse_config(configs))
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:<25}: {1}\n".format(id, param))
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