lokibot样本分析

import re
import struct
import sys

import pefile
from Cryptodome.Cipher import DES3

DESCRIPTION = "LokiBot configuration parser."
AUTHOR = "honkone"


def find_iv(pe):
    iv = -1
    t = pe.get_memory_mapped_image() if isinstance(pe, pefile.PE) else pe
    temp = re.findall(rb"""\x68...\x00.{1,10}\x68...\x00\x68...\x00\x68...\x00\x03\xc1""", t)
    if temp != []:
        (addr,) = struct.unpack_from("<I", temp[0][1:])
        addr -= 0x400000
        iv = t[addr : addr + 8]
    return iv


def try_find_iv(pe):
    dlen = 8 * 4
    t = pe.get_memory_mapped_image() if isinstance(pe, pefile.PE) else pe
    off = t.find(b"\x6a\x08\x59\xbe")
    if off == -1:
        return -1
    (addr,) = struct.unpack_from("<I", t[off + 4 :])
    addr -= 0x400000

    # Go until past next blob to \x00\x00\x00\x00
    off = t[addr + dlen + 4 :].find(b"\x00\x00\x00\x00")
    off += addr + dlen + 4 + 4
    iv = t[off : off + 8]

    # This doesn't work for all samples... still interesting that the data is in close proximity sometimes
    nul, key3, nul, key2, nul, key1 = struct.unpack_from("<I8sI8sI8s", t[off + 8 :])

    # key = f"\x08\x02\x00\x00\x03\x66\x00\x00\x18\x00\x00\x00{key1}{key2}{key3}"

    return iv


def find_conf(pe):
    dlen = 8 * 4
    t = pe.get_memory_mapped_image() if isinstance(pe, pefile.PE) else pe
    off = t.find(b"\x6a\x08\x59\xbe")
    (addr,) = struct.unpack_from("<I", t[off + 4 :])
    # print(hex(addr))
    addr -= 0x400000
    ret = [t[addr : addr + dlen]]
    dlen = 10 * 4
    off = t.find(b"\x6a\x0a\x59\xbe")
    (addr,) = struct.unpack_from("<I", t[off + 4 :])
    # print(hex(addr))
    addr -= 0x400000
    ret.append(t[addr : addr + dlen])

    return ret


def find_key(pe):
    ret = None
    t = pe.get_memory_mapped_image() if isinstance(pe, pefile.PE) else pe
    temp = re.findall(rb"""\x68...\x00\x68...\x00\x68...\x00\x03\xc1""", t)
    if temp != []:
        ret = "\x08\x02\x00\x00\x03\x66\x00\x00\x18\x00\x00\x00"
        temp = temp[0][:-2].split("\x68")[::-1]
        for a in temp:
            if a != "":
                (addr,) = struct.unpack_from("<I", a)
                # print(hex(addr))
                addr -= 0x400000
                ret += t[addr : addr + 8]
    return ret


def decoder(data):
    x_sect = None

    urls = re.findall(rb"""https?:\/\/[a-zA-Z0-9\/\.:\-_]+""", data)

    pe = None
    try:
        pe = pefile.PE(sys.argv[1])

        for sect in pe.sections:
            if ".x" in sect.Name:
                x_sect = sect
        img = pe.get_memory_mapped_image()
    except Exception:
        img = data
    if x_sect is not None:
        x = img[x_sect.VirtualAddress : x_sect.VirtualAddress + x_sect.SizeOfRawData]
        x = bytearray(x)
    else:
        x = bytearray(img)

    for i in range(len(x)):
        x[i] ^= 0xFF

    temp = re.findall(rb"""https?:\/\/[a-zA-Z0-9\/\.:\-_]+""", x)
    urls += temp

    urls = [x for x in urls if x not in ("http://www.ibsensoftware.com/", "")]

    # Try to decrypt onboard config then
    if not urls:
        temp = ""
        if pe is None:
            pe = data
        key = find_key(pe)
        # iv = try_find_iv(pe)
        iv = find_iv(pe)
        confs = find_conf(pe)
        if iv not in ["", -1] and confs != []:
            for conf in confs:
                dec = DES3.new(key[12:], DES3.MODE_CBC, iv)
                temp += dec.decrypt(conf)
            temp_urls = re.findall(rb"""[a-zA-Z0-9\/\.:\-_]{6,}""", temp)
            urls += temp_urls

    return urls


def extract_config(filebuf):
    urls = decoder(filebuf)
    return {"address": [url.decode() for url in urls]}


if __name__ == "__main__":
    with open(sys.argv[1], "rb") as f:
        data = f.read()

    print(extract_config(data))