# Detecting Ramnit 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 ramnitscan.py volatility/plugins/malware # 3. python vol.py ramnitconfig -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 socket import inet_ntoa from collections import OrderedDict try: import yara has_yara = True except ImportError: has_yara = False ramnit_sig = { 'namespace1' : 'rule Ramnit { \ strings: \ $guid = "{%08X-%04X-%04X-%04X-%08X%04X}" \ $md5_magic_1 = "15Bn99gT" \ $md5_magic_2 = "1E4hNy1O" \ $init_dga = { C7 ?? ?? ?? ?? ?? FF FF FF FF FF ?? ?? ?? ?? ?? FF ?? ?? ?? ?? ?? FF ?? ?? ?? ?? ?? E8 ?? ?? ?? ?? 0B C0 75 ?? } \ $xor_secret = { 8A ?? ?? 32 ?? 88 ?? 4? 4? E2 ?? } \ $init_function = { FF 35 [4] 68 [4] 68 [2] 00 00 68 [4] E8 [4] FF 35 [4] 68 [4] 68 [2] 00 00 68 [4] E8 [4] FF 35 [4] 68 [4] 68 [2] 00 00 68 [4] E8 [4] FF 35 [4] 68 [4] 68 [2] 00 00 68 [4] E8 } \ $dga_rand_int = { B9 1D F3 01 00 F7 F1 8B C8 B8 A7 41 00 00 } \ $cookies = "cookies4.dat" \ $s3 = "pdatesDisableNotify" \ $get_domains = { a3 [4] a1 [4] 80 3? 00 75 ?? c7 05 [4] ff ff ff ff ff 35 [4] ff 35 [4] ff 35 [4] e8 } \ $add_tld = { 55 8B EC 83 ?? ?? 57 C7 ?? ?? 00 00 00 00 B? ?? ?? ?? ?? 8B ?? ?? 3B ?? ?? 75 ?? 8B ?? } \ $get_port = { 90 68 [4] 68 [4] FF 35 [4] FF 35 [4] E8 [4] 83 } \ condition: $init_dga and $init_function and 2 of ($guid, $md5_magic_*, $cookies, $s3) and any of ( $get_port, $add_tld, $dga_rand_int, $get_domains, $xor_secret)}' } # MZ Header MZ_HEADER = b"\x4D\x5A\x90\x00" # XOR key pattern XOR_KEY_PATTERNS = [re.compile("\x68\x3C\x01\x00\x00\x68\x20", re.DOTALL)] # Flag FLAG = {0x0: "Disable", 0x1: "Enable"} class ramnitConfig(taskmods.DllList): """Parse the Ramnit 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 xor(self, encoded, xor_key): count = 0 decode = [] key_len = len(xor_key) for n in range(len(encoded)): if count == 0: count = key_len - 1 decode.append(chr(ord(encoded[n]) ^ ord(xor_key[count]))) count -= 1 return "".join(decode) def parse_config(self, pe, data, base): p_data = OrderedDict() p_data["DGA Damain No"] = unpack_from("I", data, base)[0] p_data["DGA Damain Seed"] = unpack_from(">I", data, base + 4)[0] p_data["Magick Check"] = FLAG[unpack_from("I", data, base + 8)[0]] p_data["Magick"] = unpack_from(">I", data, base + 0xc)[0] p_data["Use IP Address"] = FLAG[unpack_from("I", data, base + 0x10)[0]] p_data["IP Address"] = inet_ntoa(data[base + 0x14:base + 0x18]) p_data["Port"] = unpack_from("I", data, base + 0x18)[0] key_len = unpack_from("I", data, base + 0x1c)[0] p_data["XOR key length"] = key_len for pattern in XOR_KEY_PATTERNS: mk = re.search(pattern, data) if mk: (resource_name_rva, ) = unpack("=I", data[mk.start() - 4:mk.start()]) rn_addr = pe.get_physical_by_rva(resource_name_rva - pe.NT_HEADERS.OPTIONAL_HEADER.ImageBase) xor_key = data[rn_addr:rn_addr + key_len] else: xor_key = "" outfd.write("[!] Not found XOR key.\n") domain_encoded_data = data[base + 0x20:base + 0x15c].replace("\0","") botnet_encoded_data = data[base + 0x15c:base + 0x1ca].replace("\0","") encoded_data_1 = data[base + 0x1ca:base + 0x240].replace("\0","") encoded_data_2 = data[base + 0x240:base + 0x2b6].replace("\0","") rc4_encoded_data = data[base + 0x2b6:base + 0x2f1].replace("\0","") p_data["Hardcode Domain"] = self.xor(domain_encoded_data, xor_key) p_data["Botnet name"] = self.xor(botnet_encoded_data, xor_key) p_data["Unknown 1"] = self.xor(encoded_data_1, xor_key) p_data["Unknown 2"] = self.xor(encoded_data_2, xor_key) p_data["RC4 Key"] = self.xor(rc4_encoded_data, xor_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=ramnit_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 = [] # resource PE search dll_index = data.rfind(MZ_HEADER) dll_data = data[dll_index:] try: pe = pefile.PE(data=dll_data) except: outfd.write("[!] Can't mapped PE.\n") continue for section in pe.sections: if ".data" in section.Name: data_address = section.PointerToRawData config_data.append(self.parse_config(pe, dll_data, data_address)) 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))