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import volatility.plugins.taskmods as taskmods |
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import volatility.win32.tasks as tasks |
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import volatility.utils as utils |
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import volatility.debug as debug |
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import volatility.plugins.malware.malfind as malfind |
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import re |
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import pefile |
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from struct import unpack, unpack_from, pack |
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from collections import OrderedDict |
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try: |
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import yara |
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has_yara = True |
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except ImportError: |
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has_yara = False |
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try: |
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import aplib |
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has_aplib = True |
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except ImportError: |
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has_aplib = False |
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ursnif_sig = { |
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'namespace1' : 'rule Ursnif { \ |
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strings: \ |
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$a1 = "soft=%u&version=%u&user=%08x%08x%08x%08x&server=%u&id=%u&crc=%x"\ |
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$b1 = "client.dll" fullword\ |
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$c1 = "version=%u"\ |
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$c2 = "user=%08x%08x%08x%08x"\ |
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$c3 = "server=%u"\ |
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$c4 = "id=%u"\ |
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$c5 = "crc=%u"\ |
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$c6 = "guid=%08x%08x%08x%08x"\ |
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$c7 = "name=%s"\ |
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$c8 = "soft=%u"\ |
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$d1 = "%s://%s%s"\ |
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$d2 = "PRI \x2A HTTP/2.0"\ |
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$e1 = { A1 ?? ?? ?? 00 35 E7 F7 8A 40 50 }\ |
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$e2 = { 56 56 56 6A 06 5? FF ?? ?? ?? ?? 00 }\ |
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$f1 = { 56 57 BE ?? ?? ?? ?? 8D ?? ?? A5 A5 A5 }\ |
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$f2 = { 35 8F E3 B7 3F }\ |
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$f3 = { 35 0A 60 2E 51 }\ |
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condition: $a1 or ($b1 and 3 of ($c*)) or (5 of ($c*)) or ($b1 and all of ($d*)) or all of ($e*) or all of ($f*)}' |
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} |
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magic = "J[1J]" |
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CONFIG_PATTERNS = [ |
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re.compile("\x3D\xB7\x00\x00\x00\x0F\x84(...)\x00\xA1(....)\xC7(..)(....)\xC6(..)(.)\xC7(.)(....)", re.DOTALL), |
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re.compile("\x3D\xB7\x00\x00\x00\x0F\x84(....)\x48\x8B\x05(....)\x48\x8D\x0D(....)(\x45\x8D)(..)\x48\x89(..)\x48\x8D\x0D(....)(\x33\xD2)", re.DOTALL), |
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] |
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RSA_PATTERNS = [ |
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re.compile("\x68(....)\x8D\x85(....)\x50\xE8(....)\x68(....)\x8D\x85(....)\x50\xE8(....)\x6A\x11", re.DOTALL), |
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re.compile("\x57\x48\x83\xEC\x20\x4C\x8D\x0D(....)(\x4C\x8D)(...)\x48\x8B\xF1", re.DOTALL), |
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] |
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DT_STR = 1 |
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idx_list = { |
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0x0d20203c: ["lang_id", DT_STR], |
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0x11271c7f: ["sleep_time", DT_STR], |
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0x18a632bb: ["time_value", DT_STR], |
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0x31277bd5: ["SetWaitableTimer_value(CRC_TASKTIMEOUT)", DT_STR], |
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0x4b214f54: ["tor64_dll", DT_STR], |
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0x4fa8693e: ["serpent_key", DT_STR], |
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0x510f22d2: ["c2_tor_domain", DT_STR], |
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0x556aed8f: ["server", DT_STR], |
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0x584e5925: ["SetWaitableTimer_value", DT_STR], |
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0x602c2c26: ["capture_window_title?(CRC_KEYLOGLIST)", DT_STR], |
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0x656b798a: ["botnet", DT_STR], |
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0x6de85128: ["not_use(CRC_BCTIMEOUT)", DT_STR], |
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0x73177345: ["dga_base_url", DT_STR], |
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0x746ce763: ["movie_capture", DT_STR], |
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0x75e6145c: ["c2_domain", DT_STR], |
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0x758a4250: ["check_vm", DT_STR], |
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0x955879a6: ["SetWaitableTimer_value(CRC_SENDTIMEOUT)", DT_STR], |
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0x9fd13931: ["SOCKS_backconnect_server(CRC_BCSERVER)", DT_STR], |
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0xacc79a02: ["SetWaitableTimer_value(CRC_KNOCKERTIMEOUT)", DT_STR], |
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0xb892845a: ["tor_server3", DT_STR], |
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0xc61efa7a: ["dga_tld", DT_STR], |
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0xd0665bf6: ["c2_domain", DT_STR], |
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0xd7a003c9: ["SetWaitableTimer_value(CRC_CONFIGTIMEOUT)", DT_STR], |
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0xdf351e24: ["tor32_dll", DT_STR], |
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0xefc574ae: ["dga_seed", DT_STR], |
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0xec99df2e: ["ip_check_url", DT_STR], |
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0xea9ea760: ["p2p_bootstrap", DT_STR], |
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} |
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class ursnifConfig(taskmods.DllList): |
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"""Parse the Ursnif configuration""" |
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@staticmethod |
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def is_valid_profile(profile): |
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return (profile.metadata.get('os', 'unknown') == 'windows'), profile.metadata.get('memory_model', '32bit') |
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def get_vad_base(self, task, address): |
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for vad in task.VadRoot.traverse(): |
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if address >= vad.Start and address < vad.End: |
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return vad.Start, vad.End |
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return None |
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def parse_config(self, data): |
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p_data = OrderedDict() |
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(count,) = unpack_from("<Q", data, 0x0) |
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for i in range(count): |
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(idx, flags, off, uid) = unpack_from("<LLQQ", data, 8 + i * 24) |
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field = "unknown" |
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off += 8 + i * 24 |
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if idx in idx_list: |
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field = idx_list[idx][0] |
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else: |
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field = hex(idx) |
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p_data[field] = data[off:].split("\x00")[0] |
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return p_data |
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def decode_data(self, data, pe, offset): |
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xor_data = unpack("=H", data[offset:offset + 2])[0] |
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xor_data2 = 0xCAFA |
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data_len = xor_data ^ unpack("=H", data[offset + 2:offset + 4])[0] |
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offset += 4 |
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result = "" |
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for i in range(0, data_len, 2): |
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work = xor_data ^ xor_data2 ^ unpack("=H", data[offset + i:offset + 2 + i])[0] |
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xor_data2 = (xor_data2 * (i + 2) ) & 0xffff |
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result += pack("H", (work & 0xffff)) |
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result = result[:data_len] |
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return result |
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def pe_magic_check(self, data): |
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mz_magic = unpack_from("=2s", data, 0x0)[0] |
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nt_magic = unpack_from("<H", data, 0x3c)[0] |
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if mz_magic == "\x00\x00": |
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data = "\x4d\x5a" + data[2:] |
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data = data[:nt_magic] + "\x50\x45" + data[nt_magic + 2:] |
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return data |
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def parse_joinned_data(self, data): |
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data = self.pe_magic_check(data) |
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config_data = [] |
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fnames = [] |
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for m in re.finditer(magic + "\x00.", data): |
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xor_dword = 0 |
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magic_dword = data[m.start():m.start() + 4] |
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if (magic_dword[0:1] == "J1" or magic_dword[3] == "\0"): |
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(flags, crc32_name, addr, size) = unpack_from("<LLLL", data, m.start() + 4) |
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print("[+] magic: {0} flags: 0x{1:X} crc32_name: 0x{2:X} addr: 0x{3:X} size: 0x{4:X}".format( |
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repr(magic_dword), flags, crc32_name, addr, size)) |
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elif (magic_dword[0:1] == "JJ" or (ord(magic_dword[3]) & 1) == 1): |
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(xor_dword, crc32_name, addr, size) = unpack_from("<LLLL", data, m.start() + 4) |
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print("[+] magic: {0} xor: 0x{1:X} crc32_name: 0x{2:X} addr: 0x{3:X} size: 0x{4:X}".format( |
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repr(magic_dword), xor_dword, crc32_name, addr, size)) |
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else: |
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break |
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if size > 0x80000: |
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print("[!] size is too large, skipped this entry") |
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continue |
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try: |
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offset = addr |
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except: |
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print("[!] This PE is old Ursnif (not DreamBot)") |
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(addr, size, crc32_name, flags) = unpack_from( |
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"<LLLL", data, m.start() + 4) |
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print("[+] magic: {0} addr: 0x{1:X} size: 0x{2:X} crc32_name: 0x{3:X} flags: 0x{4:X}".format( |
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repr(magic_dword), addr, size, crc32_name, flags)) |
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offset = addr |
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try: |
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joined_res = data[offset:offset + size] |
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dec_data = aplib.decompress(joined_res).do()[0] |
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except: |
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pe = pefile.PE(data=data) |
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offset = pe.get_offset_from_rva(addr) |
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joined_res = data[offset:offset + size] |
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dec_data = aplib.decompress(joined_res).do()[0] |
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if (xor_dword != 0): |
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mod_data = "" |
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for i in range(min(4, size + 1)): |
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mod_data += chr(ord(dec_data[i]) ^ ((xor_dword >> 8 * i) & 0xff)) |
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if (size >= 4): |
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mod_data += dec_data[4:] |
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dec_data = mod_data |
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if crc32_name in (0x4f75cea7, 0x9e154a0c): |
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fname = "ursnif_client32.bin" |
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open(fname, "wb").write(dec_data) |
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print("[+] dumped 32 bit client dll: {0}".format(fname)) |
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fnames.append(dec_data) |
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elif crc32_name in (0x90f8aab4, 0x41982e1f): |
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fname = "ursnif_client64.bin" |
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open(fname, "wb").write(dec_data) |
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print("[+] dumped 64 bit client dll: {0}".format(fname)) |
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elif crc32_name in (0xe1285e64,): |
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fname = "ursnif_public_key.bin" |
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open(fname, "wb").write(dec_data) |
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print("[+] dumped public key: {0}".format(fname)) |
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elif crc32_name in (0xd722afcb, 0x8365b957, 0x8fb1dde1): |
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fname = "ursnif_st_config.bin" |
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open(fname, "wb").write(dec_data) |
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print("[+] dumped static config: {0}".format(fname)) |
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config_data.append(self.parse_config(dec_data)) |
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else: |
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fname = "ursnif_" + hex(addr) + "_ap32_dec.bin" |
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open(fname, "wb").write(dec_data) |
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print("[+] dumped: {0}".format(fname)) |
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for fname in fnames: |
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config_data = self.parse_joinned_data(fname) |
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return config_data |
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def calculate(self): |
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if not has_yara: |
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debug.error("Yara must be installed for this plugin") |
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if not has_aplib: |
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debug.error("Aplib must be installed for this plugin") |
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addr_space = utils.load_as(self._config) |
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os, memory_model = self.is_valid_profile(addr_space.profile) |
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if not os: |
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debug.error("This command does not support the selected profile.") |
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rules = yara.compile(sources=ursnif_sig) |
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for task in self.filter_tasks(tasks.pslist(addr_space)): |
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scanner = malfind.VadYaraScanner(task=task, rules=rules) |
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for hit, address in scanner.scan(): |
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vad_base_addr, end = self.get_vad_base(task, address) |
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proc_addr_space = task.get_process_address_space() |
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data = proc_addr_space.zread(vad_base_addr, end - vad_base_addr) |
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config_data = [] |
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config_data = self.parse_joinned_data(data) |
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if not config_data: |
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p_data = OrderedDict() |
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data = self.pe_magic_check(data) |
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try: |
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pe = pefile.PE(data=data) |
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except: |
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continue |
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imagebase = pe.NT_HEADERS.OPTIONAL_HEADER.ImageBase |
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for pattern in CONFIG_PATTERNS: |
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m = re.search(pattern, data) |
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if m: |
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if pe.FILE_HEADER.Machine in (pefile.MACHINE_TYPE['IMAGE_FILE_MACHINE_IA64'], pefile.MACHINE_TYPE['IMAGE_FILE_MACHINE_AMD64']): |
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c2_num = unpack("b", data[m.start(7) + 19])[0] |
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else: |
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c2_num = unpack("b", data[m.start(6)])[0] |
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if c2_num >= 16: |
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c2_num = 1 |
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for i in range(c2_num): |
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if pe.FILE_HEADER.Machine in (pefile.MACHINE_TYPE['IMAGE_FILE_MACHINE_IA64'], pefile.MACHINE_TYPE['IMAGE_FILE_MACHINE_AMD64']): |
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c2_addr = m.start(4) + unpack("=I", data[m.start(3):m.start(3) + 4])[0] |
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c2_table_offset = unpack("=Q", data[c2_addr + (8 * i):c2_addr + 8 + (8 * i)])[0] - imagebase |
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else: |
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c2_addr = unpack("=I", data[m.start(4):m.start(4) + 4])[0] - imagebase |
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c2_table_offset = unpack("=I", data[c2_addr + (4 * i):c2_addr + 4 + (4 * i)])[0] - imagebase |
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try: |
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c2 = self.decode_data(data, pe, c2_table_offset) |
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except: |
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c2 = "Decode fail" |
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p_data["Server " + str(i)] = c2 |
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if pe.FILE_HEADER.Machine in (pefile.MACHINE_TYPE['IMAGE_FILE_MACHINE_IA64'], pefile.MACHINE_TYPE['IMAGE_FILE_MACHINE_AMD64']): |
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serpent_key_offset = m.start(8) + unpack("=I", data[m.start(7):m.start(7) + 4])[0] |
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else: |
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serpent_key_offset = unpack("=I", data[m.start(8):m.start(8) + 4])[0] - imagebase |
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try: |
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serpent_key = self.decode_data(data, pe, serpent_key_offset) |
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except: |
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serpent_key = "Decode fail" |
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p_data["Serpent key"] = serpent_key |
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for pattern in RSA_PATTERNS: |
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m = re.search(pattern, data) |
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if m: |
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if pe.FILE_HEADER.Machine in (pefile.MACHINE_TYPE['IMAGE_FILE_MACHINE_IA64'], pefile.MACHINE_TYPE['IMAGE_FILE_MACHINE_AMD64']): |
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rsa_key_offset = m.start(2) + unpack("=I", data[m.start(1):m.start(1) + 4])[0] |
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rsa_key = data[rsa_key_offset + 4:rsa_key_offset + 0x44] |
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rsa_mod = data[rsa_key_offset + 0x44:rsa_key_offset + 0x84] |
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else: |
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rsa_key_offset = unpack("=I", data[m.start(1):m.start(1) + 4])[0] - imagebase |
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rsa_key = data[rsa_key_offset:rsa_key_offset + 0x40] |
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mod_offset = unpack("=I", data[m.start(4):m.start(4) + 4])[0] - imagebase |
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rsa_mod = data[mod_offset:mod_offset + 0x40] |
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p_data["RSA key"] = rsa_key.encode("hex") |
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p_data["RSA modulus"] = rsa_mod.encode("hex") |
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config_data.append(p_data) |
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yield task, vad_base_addr, end, hit, memory_model, config_data |
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break |
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def render_text(self, outfd, data): |
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delim = '-' * 70 |
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for task, start, end, malname, memory_model, config_data in data: |
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outfd.write("{0}\n".format(delim)) |
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|
outfd.write("Process: {0} ({1})\n\n".format(task.ImageFileName, task.UniqueProcessId)) |
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outfd.write("[Config Info]\n") |
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|
for p_data in config_data: |
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|
for id, param in p_data.items(): |
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|
outfd.write("{0:<16}: {1}\n".format(id, param)) |
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|