finish code decryption and reloc impl

notes2.txt

@@ -20,5 +20,5 @@ edx <- STUB_FRAME (??)
 
 val_3 -> {???}{7 bits select offset for something}{12 bits size decrypted data}
 offset_1 -> key1
-offset_2 -> {byte1:last_bit = skip_verify_offset_1}{verify_byte}{key2 as word}
+offset_2 -> {byte1:last_bit = no_derive_key_from_mac}{verify_byte}{key2 as word}
 offset_3 -> some addr?

obfu_block.py

@@ -5,21 +5,10 @@ from keystone import *
 import pefile
 import json
 import re
-import numpy as np
 
 # Set to binary name
 BIN_NAME = "sppsvc.exe"
 
-# Set to function to be analyzed
-# ANLZ_FUNC = "?VerifyPKeyByInstalledPidConfig@CSLSLicenseManager@@IBEJPAVCSLPKey@@PBGPAUtagPKEY_BASIC_INFO@@PAPAGPAUDECODED_PKEY_DATA@@@Z"
-ANLZ_FUNC = "_wmain"
-
-# These magic regexes are derived from the byte markers in notes.txt
-PUSH_REGEX = rb"(?:\x8dd\$\xfc\x89[\x04\x0c\x14\x1c,4<]\$|[PQRSUVW]){2}\x8d[x\x05\r\x15\x1d-5=].{4}"
-STUB_RET4_REGEX = rb"\x8b[DLT\\lt\|]\$\x04\xc2\x04\x00"
-STUB_RET0_REGEX = rb"\x87[\x04\x0c\x14\x1c,4<]\$\xc3"
-STUB_MAX_SIZE = 0x40 # Maximum size of jump stub
-
 REG_NAMES = {
     19: "EAX",
     20: "EBP",
@@ -42,13 +31,30 @@ ks = Ks(KS_ARCH_X86, KS_MODE_32)
 md = Cs(CS_ARCH_X86, CS_MODE_32)
 md.detail = True
 md.skipdata = True
-ql = Qiling(["./rootfs/sppsvc.exe"], "./rootfs")
+ql = Qiling(["./rootfs/sppsvc.exe"], "./rootfs", verbose=QL_VERBOSE.OFF)
 image_start = ql.loader.images[0].base
 image_end = ql.loader.images[0].end
 image_size = image_end - image_start
 pe = pefile.PE(data=ql.mem.read(image_start, image_size))
 
-num_obd = ql.unpack(ql.mem.read(sym_data_inv["?g_nNumObfuscatedBlockData@WARBIRD@@3KA"], 4))
+def mem_read_int(addr):
+    return ql.unpack(ql.mem.read(addr, 4))
+
+def array_read_int(array, offset):
+    return int.from_bytes(array[offset:offset+4], "little")
+
+def array_write_int(array, offset, val):
+    arr_copy = list(array)
+    val_bytes = val.to_bytes(4, "little")
+    
+    for i in range(4):
+        arr_copy[offset + i] = val_bytes[i]
+    
+    return arr_copy
+
+stub_frame = 0x010BE265
+
+num_obd = mem_read_int(sym_data_inv["?g_nNumObfuscatedBlockData@WARBIRD@@3KA"])
 obd_addr = sym_data_inv["?g_ObfuscatedBlockData@WARBIRD@@3PAU_OBFUSCATED_BLOCK_DATA@1@A"]
 obd = []
 
@@ -56,11 +62,17 @@ for i in range(num_obd):
     obf_block = []
     
     for j in range(5):
-        obf_block.append(ql.unpack(ql.mem.read(obd_addr + 4*(5*i + j), 4)))
+        obf_block.append(mem_read_int(obd_addr + 4*(5*i + j)))
     
     obd.append(obf_block)
 
-stub_frame = 0x120f989
+num_relocs = mem_read_int(sym_data_inv["?g_PrivateRelocationsTable@WARBIRD@@3VCPrivateRelocationsTable@1@B"])
+reloc_addr = sym_data_inv["?g_PrivateRelocationsTable@WARBIRD@@3VCPrivateRelocationsTable@1@B"] + 4
+private_relocs = []
+
+for i in range(num_relocs):
+    private_relocs.append(mem_read_int(reloc_addr + 4*i))
+
 stub_frame_offset = stub_frame - image_start
 
 first = 0
@@ -87,6 +99,9 @@ while True:
         last_prev = last
         sum_diff = (obd[index][0] + obd[index][3]) % (1 << 32)
     
+    if first > last:
+        raise Exception("Offset not found in block table!")
+    
     print(f"XOR {hex(xor_value)} SUMDIFF {hex(sum_diff)} INDEX {hex(index)}")
 
 val1 = (obd[index][1] + obd[index][0]) % (1 << 32)
@@ -101,9 +116,16 @@ enc_bytes = ql.mem.read(xor_plus_binstart, data_size + 1)
 dec_bytes = [0] * data_size
 chksum = 0xa5
 
-for i in range(data_size - 1, 0, -1):
+if val2 & 0x1000000 == 0:
+    raise Exception("USES MAC-DERIVED KEY")
+
+for i in range(data_size - 1, -1, -1):
     enc_byte = enc_bytes[i]
-    b = enc_bytes[i - 1]
+    
+    if i > 0:
+        b = enc_bytes[i - 1]
+    else:
+        b = 0
     
     if i % 2 == 1:
         if (enc_byte ^ val1_bytes[3]) % 2 == 1:
@@ -127,5 +149,57 @@ for i in range(data_size - 1, 0, -1):
             dec_byte = (a ^ b) >> 1
     
     chksum ^= dec_byte
-    print(hex(dec_byte))
     dec_bytes[i] = dec_byte
+
+if chksum != val2_bytes[2]:
+    raise Exception("CHECKSUM FAILED!")
+
+print(dec_bytes)
+
+first = 0
+last = num_relocs - 1
+
+while last >= first:
+    index = (first + last) // 2
+    addr = private_relocs[index] & 0xFFFFFFF
+    
+    if xor_value >= addr:
+        if xor_value == addr:
+            first = (first + last) // 2
+            break
+        
+        first = index + 1
+    else:
+        last = index - 1
+
+index = first
+
+while index < num_relocs:
+    addr = private_relocs[index] & 0xFFFFFFF
+    
+    if addr >= (xor_value + data_size):
+        break
+    
+    offset = 0
+    ofmode = (private_relocs[index] >> 28) & 3
+    
+    if ofmode == 1:
+        offset = -xor_plus_binstart % (1 << 32)
+    elif ofmode == 2:
+        offset = xor_plus_binstart
+    elif ofmode == 3:
+        offset = 0
+    
+    if ((private_relocs[index] >> 30) & 3) == 2:
+        print(hex(addr - xor_value), hex(offset))
+        val = array_read_int(dec_bytes, addr - xor_value)
+        val = (val + offset) % (1 << 32)
+        dec_bytes = array_write_int(dec_bytes, addr - xor_value, val)
+        print(dec_bytes)
+    
+    index += 1
+
+dec_bytes = bytes(dec_bytes)
+
+for instr in md.disasm(dec_bytes, 0):
+    print(instr)

peacestone.py

@@ -92,7 +92,7 @@ if __name__ == "__main__":
         ret = 0
         
         for i, instr in enumerate(instrs):
-            print(instr)
+            # print(instr)
             
             if instr.mnemonic == "ret" and instr.op_str == "4":
                 ret = i
@@ -138,7 +138,7 @@ if __name__ == "__main__":
         jmp_insert_addr = 0
         
         for inst in instrs[max(0,stub_start_index-4):stub_start_index][::-1]:
-            print(inst)
+            # print(inst)
             if inst.bytes in push_instrs:
                 # ql.mem.write(inst.address, NOP * len(inst.bytes))
                 jmp_insert_addr = inst.address
@@ -165,7 +165,12 @@ if __name__ == "__main__":
         print("JUMP TARGET @ " + hex(next_addr))
         print(ql.arch.regs.esp)
         
-        f.write(f"J R4 S {hex(jmp_insert_addr)} H {hex(handler_addr)} N {hex(next_addr)}\n")
+        if handler_addr in sym_data:
+            handler_name = sym_data[handler_addr]
+        else:
+            handler_name = hex(handler_addr)
+        
+        f.write(f"J R4 S {hex(jmp_insert_addr)} H {handler_name} N {hex(next_addr)}\n")
         
         # input()
         print()