# Detecting QuasarRAT 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 quasarscan.py volatility/plugins/malware # 3. python vol.py quasarconfig -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 hashlib from base64 import b64decode from collections import OrderedDict try: import yara has_yara = True except ImportError: has_yara = False try: from Crypto.Cipher import AES has_crypto = True except ImportError: has_crypto = False try: from pbkdf2 import PBKDF2 has_pbkdf2 = True except ImportError: has_pbkdf2 = False quasar_sig = { 'namespace1' : 'rule Quasar { \ strings: \ $quasarstr1 = "Client.exe" wide \ $quasarstr2 = "({0}:{1}:{2})" wide \ $sql1 = "SELECT * FROM Win32_DisplayConfiguration" wide \ $sql2 = "{0}d : {1}h : {2}m : {3}s" wide \ $sql3 = "SELECT * FROM FirewallProduct" wide \ $net1 = "echo DONT CLOSE THIS WINDOW!" wide \ $net2 = "freegeoip.net/xml/" wide \ $net3 = "http://api.ipify.org/" wide \ $resource = { 52 00 65 00 73 00 6F 00 75 00 72 00 63 00 65 00 73 00 00 17 69 00 6E 00 66 00 6F 00 72 00 6D 00 61 00 74 00 69 00 6F 00 6E 00 00 } \ condition: ((all of ($quasarstr*) or all of ($sql*)) and $resource) or all of ($net*)}' } # Config pattern CONFIG_PATTERNS = [re.compile("\x52\x00\x65\x00\x73\x00\x6F\x00\x75\x00\x72\x00\x63\x00\x65\x00\x73\x00\x00\x17\x69\x00\x6E\x00\x66\x00\x6F\x00\x72\x00\x6D\x00\x61\x00\x74\x00\x69\x00\x6F\x00\x6E\x00\x00\x80", re.DOTALL), re.compile("\x61\x00\x70\x00\x69\x00\x2E\x00\x69\x00\x70\x00\x69\x00\x66\x00\x79\x00\x2E\x00\x6F\x00\x72\x00\x67\x00\x2F\x00\x00\x03\x5C\x00\x00", re.DOTALL), re.compile("\x3C\x00\x2F\x00\x73\x00\x74\x00\x79\x00\x6C\x00\x65\x00\x3E\x00\x00\x03\x5C\x00\x00\x80", re.DOTALL)] idx_list = { 0: ["VERSION", True], 1: ["HOSTS", True], 2: ["KEY (Base64)", False], 3: ["AUTHKEY (Base64)", False], 4: ["SUBDIRECTORY", True], 5: ["INSTALLNAME",True], 6: ["MUTEX", True], 7: ["STARTUPKEY", True], 8: ["ENCRYPTIONKEY", False], 9: ["TAG", True], 10: ["LOGDIRECTORYNAME",True ], 11: ["unknown1", True], 12: ["unknown2", True] } idx_list_2 = { 0: ["VERSION", True], 1: ["HOSTS", True], 2: ["KEY (Base64)", False], 3: ["SUBDIRECTORY", True], 4: ["INSTALLNAME",True], 5: ["MUTEX", True], 6: ["STARTUPKEY", True], 7: ["ENCRYPTIONKEY", False], 8: ["TAG", True] } class quasarConfig(taskmods.DllList): """Parse the QuasarRAT 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 decrypt_string(self, key, configs, mode, idx): p_data = OrderedDict() for i, config in enumerate(configs): if idx[i][1] == True: if len(configs) < 10: config = b64decode(config) aes_iv = config[:16] cipher = AES.new(key, mode, IV=aes_iv) value = re.sub("[\x00-\x19]" ,"" , cipher.decrypt(config[16:])) else: config = b64decode(config) aes_iv = config[32:48] cipher = AES.new(key, mode, IV=aes_iv) value = re.sub("[\x00-\x19]" ,"" , cipher.decrypt(config[48:])) else: value = config p_data[idx[i][0]] = value return p_data def parse_config(self, configs): if len(configs) > 10: idx = idx_list key, salt = configs[8], 'BFEB1E56FBCD973BB219022430A57843003D5644D21E62B9D4F180E7E6C33941'.decode('hex') generator = PBKDF2(key, salt, 50000) aes_key = generator.read(16) else: idx = idx_list_2 aes_key = hashlib.md5(configs[7]).digest() if(len(configs) > 12): mode = AES.MODE_CFB else: mode = AES.MODE_CBC p_data = self.decrypt_string(aes_key, configs, mode, idx) return p_data def calculate(self): if not has_yara: debug.error("Yara must be installed for this plugin") if not has_crypto: debug.error("pycrypto must be installed for this plugin") if not has_pbkdf2: debug.error("pbkdf2 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=quasar_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 = [] offset = 0 for pattern in CONFIG_PATTERNS: mc = re.search(pattern, data) if mc: offset = mc.end() if ord(data[offset]) == 0x0: offset += 1 configs = [] if offset > 0: while 1: strings = [] string_len = ord(data[offset]) if ord(data[offset]) == 0x80 or ord(data[offset]) == 0x81: 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]) configs.append("".join(strings)) offset = offset + string_len if ord(data[offset]) < 0x20: break 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:<21}: {1}\n".format(id, param))