ByteAPK

Flutter rust bridge
ByteCTF{}，总长度45
flag被通过ffi传到rust，然后utf8转成c string,去掉了ByteCTF{和后面的},传到一个函数里面check

unsigned char arr1[] =
{
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
  0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 
  0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 
  0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 
  0x02, 0x02, 0x02, 0x02, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 
  0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 
  0x04, 0x04, 0x04, 0x04, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
unsigned int enc[32] = {
    0x0001EE59, 0x0000022A, 0x00001415, 0x00040714, 0x000013E0, 0x000008B8, 0xFFFDCEA0, 0x0000313B, 
    0x0003D798, 0xFFFFFE6B, 0x00000C4E, 0x00023884, 0x0000008D, 0x00001DB4, 0xFFFC1328, 0x00001EAC, 
    0x00043C64, 0x0000142B, 0xFFFFF622, 0x00023941, 0xFFFFEF6D, 0x0000120C, 0xFFFBD30F, 0x00001EBE, 
    0x00045158, 0xFFFFEF66, 0x00001D3F, 0x0004C46B, 0xFFFFF97A, 0x00001BFD, 0xFFFBA235, 0x00001ED2
};

__int64 __fastcall final_enc(unsigned __int8 *flag_intern, __int64 a2)
{
  __int64 v2; // x9
  __int64 v3; // x9
  __int64 v4; // x9
  __int64 v5; // x9
  __int64 v6; // x9
  __int64 v7; // x9
  __int64 v8; // x9
  __int64 v9; // x9
  unsigned int v10; // w11
  int v11; // w13
  __int64 v12; // x9
  __int64 v13; // x9
  __int64 v14; // x9
  __int64 v15; // x9
  __int64 v16; // x9
  unsigned int v18; // w10
  int v19; // w13
  __int64 v20; // x9
  __int64 v21; // x9
  __int64 v22; // x9
  __int64 v23; // x9
  __int64 v24; // x9
  unsigned int v25; // w10
  int v26; // w13
  __int64 v27; // x9
  __int64 v28; // x9
  __int64 v29; // x9
  __int64 v30; // x9
  __int64 v31; // x9
  unsigned int v32; // w8
  int v33; // w11
  unsigned __int64 v34; // x20
  __int64 v35; // x21
  unsigned int v36; // w22
  int v37; // w8
  __int64 v38; // x10
  int v39; // w9
  unsigned __int64 v40; // x8
  __int64 v41; // x9
  unsigned __int64 v42; // x10
  unsigned __int64 v43; // x8
  int v44; // w12
  int v45; // w14
  int v46; // w3
  int v47; // w13
  int v48; // w2
  int v49; // w16
  int v50; // w15
  int v51; // w17
  int v52; // w6
  int v53; // w4
  int v54; // w12
  int *v55; // x13
  __int64 v57; // [xsp+8h] [xbp-48h] BYREF
  __int64 v58; // [xsp+10h] [xbp-40h]
  unsigned __int64 v59; // [xsp+18h] [xbp-38h]

  v57 = 0LL;
  v58 = 4LL;
  if ( a2 != 36 )
    return 0LL;
  v2 = arr1[*flag_intern];
  if ( (_DWORD)v2 == 36 )
    return 0LL;
  v3 = arr1[flag_intern[v2]] + v2;
  if ( v3 == 36 )
    return 0LL;
  v4 = v3 + arr1[flag_intern[v3]];
  if ( v4 == 36 )
    return 0LL;
  v5 = v4 + arr1[flag_intern[v4]];
  if ( v5 == 36 )
    return 0LL;
  v6 = v5 + arr1[flag_intern[v5]];
  if ( v6 == 36 )
    return 0LL;
  v7 = v6 + arr1[flag_intern[v6]];
  if ( v7 == 36 )
    return 0LL;
  v8 = v7 + arr1[flag_intern[v7]];
  if ( v8 == 36 )
    return 0LL;
  v9 = v8 + arr1[flag_intern[v8]];
  if ( v9 == 36 )
    return 0LL;
  v10 = flag_intern[v9];
  if ( (char)flag_intern[v9] < 0 )
  {
    if ( v10 < 0xE0 )
    {
      v10 = flag_intern[v9 + 1] & 0x3F | ((v10 & 0x1F) << 6);
    }
    else
    {
      v11 = flag_intern[v9 + 2] & 0x3F | ((flag_intern[v9 + 1] & 0x3F) << 6);
      if ( v10 < 0xF0 )
        v10 = v11 | ((v10 & 0x1F) << 12);
      else
        v10 = flag_intern[v9 + 3] & 0x3F | (v11 << 6) & 0xFFE3FFFF | ((v10 & 7) << 18);
    }
  }
  if ( v10 != 45 )
    return 0LL;
  v12 = v9 + arr1[flag_intern[v9]];
  if ( v12 == 36 )
    return 0LL;
  v13 = v12 + arr1[flag_intern[v12]];
  if ( v13 == 36 )
    return 0LL;
  v14 = v13 + arr1[flag_intern[v13]];
  if ( v14 == 36 )
    return 0LL;
  v15 = v14 + arr1[flag_intern[v14]];
  if ( v15 == 36 )
    return 0LL;
  v16 = v15 + arr1[flag_intern[v15]];
  if ( v16 == 36 )
    return 0LL;
  v18 = flag_intern[v16];
  if ( (char)flag_intern[v16] < 0 )
  {
    if ( v18 < 0xE0 )
    {
      v18 = flag_intern[v16 + 1] & 0x3F | ((v18 & 0x1F) << 6);
    }
    else
    {
      v19 = flag_intern[v16 + 2] & 0x3F | ((flag_intern[v16 + 1] & 0x3F) << 6);
      if ( v18 < 0xF0 )
        v18 = v19 | ((v18 & 0x1F) << 12);
      else
        v18 = flag_intern[v16 + 3] & 0x3F | (v19 << 6) & 0xFFE3FFFF | ((v18 & 7) << 18);
    }
  }
  if ( v18 != 45 )
    return 0LL;
  v20 = v16 + arr1[flag_intern[v16]];
  if ( v20 == 36 )
    return 0LL;
  v21 = v20 + arr1[flag_intern[v20]];
  if ( v21 == 36 )
    return 0LL;
  v22 = v21 + arr1[flag_intern[v21]];
  if ( v22 == 36 )
    return 0LL;
  v23 = v22 + arr1[flag_intern[v22]];
  if ( v23 == 36 )
    return 0LL;
  v24 = v23 + arr1[flag_intern[v23]];
  if ( v24 == 36 )
    return 0LL;
  v25 = flag_intern[v24];
  if ( (char)flag_intern[v24] < 0 )
  {
    if ( v25 < 0xE0 )
    {
      v25 = flag_intern[v24 + 1] & 0x3F | ((v25 & 0x1F) << 6);
    }
    else
    {
      v26 = flag_intern[v24 + 2] & 0x3F | ((flag_intern[v24 + 1] & 0x3F) << 6);
      if ( v25 < 0xF0 )
        v25 = v26 | ((v25 & 0x1F) << 12);
      else
        v25 = flag_intern[v24 + 3] & 0x3F | (v26 << 6) & 0xFFE3FFFF | ((v25 & 7) << 18);
    }
  }
  if ( v25 != 45 )
    return 0LL;
  v27 = v24 + arr1[flag_intern[v24]];
  if ( v27 == 36 )
    return 0LL;
  v28 = v27 + arr1[flag_intern[v27]];
  if ( v28 == 36 )
    return 0LL;
  v29 = v28 + arr1[flag_intern[v28]];
  if ( v29 == 36 )
    return 0LL;
  v30 = v29 + arr1[flag_intern[v29]];
  if ( v30 == 36 )
    return 0LL;
  v31 = v30 + arr1[flag_intern[v30]];
  if ( v31 == 36 )
    return 0LL;
  v32 = flag_intern[v31];
  if ( (char)flag_intern[v31] < 0 )
  {
    if ( v32 < 0xE0 )
    {
      v32 = flag_intern[v31 + 1] & 0x3F | ((v32 & 0x1F) << 6);
    }
    else
    {
      v33 = flag_intern[v31 + 2] & 0x3F | ((flag_intern[v31 + 1] & 0x3F) << 6);
      if ( v32 < 0xF0 )
        v32 = v33 | ((v32 & 0x1F) << 12);
      else
        v32 = flag_intern[v31 + 3] & 0x3F | (v33 << 6) & 0xFFE3FFFF | ((v32 & 7) << 18);
    }
  }
  if ( v32 != 45 )
    return 0LL;
  v34 = 0LL;
  v35 = 0LL;
  while ( 1 )
  {
    v36 = flag_intern[v35];
    if ( (char)flag_intern[v35] < 0 )
    {
      v37 = flag_intern[v35 + 1] & 0x3F;
      if ( v36 < 0xE0 )
      {
        v35 += 2LL;
        v36 = v37 & 0xFFFFF83F | ((v36 & 0x1F) << 6);
      }
      else
      {
        v38 = v35 + 3;
        v39 = flag_intern[v35 + 2] & 0x3F | (v37 << 6);
        if ( v36 < 0xF0 )
        {
          v36 = v39 | ((v36 & 0x1F) << 12);
          v35 += 3LL;
        }
        else
        {
          v35 += 4LL;
          v36 = flag_intern[v38] & 0x3F | (v39 << 6) & 0xFFE3FFFF | ((v36 & 7) << 18);
        }
      }
    }
    else
    {
      ++v35;
    }
    if ( v36 != 45 )
      break;
LABEL_55:
    if ( v35 == 36 )
      goto LABEL_67;
  }
  if ( v36 != 0x110000 )
  {
    if ( v34 == v57 )
      sub_3B688(&v57, a2);
    *(_DWORD *)(v58 + 4 * v34++) = v36;
    v59 = v34;
    goto LABEL_55;
  }
LABEL_67:
  v40 = v34 >> 3;
  v41 = 0LL;
  if ( (v34 & 7) != 0 )
    ++v40;
  v42 = v40 + 1;
  v43 = 8LL;
  while ( --v42 )
  {
    if ( v43 > v34 )
      goto LABEL_88;
    if ( v43 - 8 >= 0x19 )
    {
      v43 = 40LL;
      v34 = 32LL;
LABEL_88:
      panic(v43, v34, (__int64)&off_801E0);
    }
    v45 = *(_DWORD *)(v58 + v41 * 4 + 8);
    v44 = *(_DWORD *)(v58 + v41 * 4 + 12);
    v46 = *(_DWORD *)(v58 + v41 * 4);
    v47 = *(_DWORD *)(v58 + v41 * 4 + 4);
    v48 = *(_DWORD *)(v58 + v41 * 4 + 16);
    v49 = *(_DWORD *)(v58 + v41 * 4 + 20);
    v50 = *(_DWORD *)(v58 + v41 * 4 + 24);
    v51 = *(_DWORD *)(v58 + v41 * 4 + 28);
    if ( v51 + v47 * v44 * v49 - (v46 + v50 + v45 * v48) == enc[v41] )
    {
      v52 = v46 * v49;
      if ( v44 - v48 - v46 * v49 + v51 * v47 + v45 + v50 == enc[v41 + 1]
        && v52 - (v48 + v51 * v47) + v45 + v50 * v44 == enc[v41 + 2] )
      {
        v53 = v48 * v46;
        if ( v47 + v48 * v46 - (v51 + v45) + v50 * v49 * v44 == enc[v41 + 3]
          && v49 * v44 + v47 + v45 * v48 - (v50 + v51 * v46) == enc[v41 + 4]
          && v52 + v47 * v44 + v45 - (v50 + v48 * v51) == enc[v41 + 5]
          && v51 - v47 + v45 * v49 + v50 - v53 * v44 == enc[v41 + 6] )
        {
          v43 += 8LL;
          v54 = v44 - v51 - (v47 + v49);
          v55 = &enc[v41];
          v41 += 8LL;
          if ( v54 + v53 + v50 * v45 == v55[7] )
            continue;
        }
      }
    }
    if ( v57 )
      c_free(v58, 4 * v57, 4LL);
    return 0LL;
  }
  if ( v57 )
    c_free(v58, 4 * v57, 4LL);
  return 1LL;
}

通过观察，注意到前面的一堆是在检验是否是UUID，后面则是一个标准的z3题目。
exp

from regadgets import *
from z3 import *

enc = [
    0x0001EE59, 0x0000022A, 0x00001415, 0x00040714, 0x000013E0, 0x000008B8, 0xFFFDCEA0, 0x0000313B, 
    0x0003D798, 0xFFFFFE6B, 0x00000C4E, 0x00023884, 0x0000008D, 0x00001DB4, 0xFFFC1328, 0x00001EAC, 
    0x00043C64, 0x0000142B, 0xFFFFF622, 0x00023941, 0xFFFFEF6D, 0x0000120C, 0xFFFBD30F, 0x00001EBE, 
    0x00045158, 0xFFFFEF66, 0x00001D3F, 0x0004C46B, 0xFFFFF97A, 0x00001BFD, 0xFFFBA235, 0x00001ED2
]

for j in range(4):
    x = [BitVec(f"x{i+1}", 32) for i in range(8)]
    x1, x2, x3, x4, x5, x6, x7, x8 = tuple(i for i in x)
    s = Solver()
    for i in x:
        s.add(i > 0x20, i < 0x80)
    s.add(x8 + x2 * x4 * x6 - (x1 + x7 + x3 * x5) == enc[0+j*8])
    v52 = x1 * x6
    s.add(x4 - x5 - x1 * x6 + x8 * x2 + x3 + x7 == enc[1+j*8])
    s.add(v52 - (x5 + x8 * x2) + x3 + x7 * x4 == enc[2+j*8])
    v53 = x5 * x1
    s.add(x2 + x5 * x1 - (x8 + x3) + x7 * x6 * x4 == enc[3+j*8])
    s.add(x6 * x4 + x2 + x3 * x5 - (x7 + x8 * x1) == enc[4+j*8])
    s.add(v52 + x2 * x4 + x3 - (x7 + x5 * x8) == enc[5+j*8])
    s.add(x8 - x2 + x3 * x6 + x7 - v53 * x4 == enc[6+j*8])
    v54 = x4 - x8 - (x2 + x6)
    s.add(v54 + v53 + x7 * x3 == enc[7+j*8])
    
    if s.check() == sat:
        m = s.model()
        for i in x:
            l = m[i].as_long()
            print(l2b(l).decode(),end='')
            # 32e750c8fb214562af22973fb5176b9c
            # ByteCTF{32e750c8-fb21-4562-af22-973fb5176b9c}

x64_extension

AES-256 密钥扩增魔改

from regadgets import *
k = bytes([0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f])
iv = bytes([0xff, 0xfe, 0xfd, 0xfc, 0xfb, 0xfa, 0xf9, 0xf8, 0xf7, 0xf6, 0xf5, 0xf4, 0xf3, 0xf2, 0xf1, 0xf0])
a = AES(k)
data = open('flag.txt.enc', 'rb').read()
print(a.decrypt_cbc(data, iv))
# b"Hey Sekai CTF Player, I hope you are fine and are enjoying the CTF. Keep going, here is your reward! The flag is SEKAI{Pl34Se_It'5_jUs7_@_wAaaarmUp}\n"

SEKAI{Pl34Se_It'5_jUs7_@_wAaaarmUp}

picStore(re)

https://impartial-poinsettia-a05.notion.site/Lua-953ca64d37c9478b82d394ea2f2a0ca1#ce05742c1bd04285ba87bf4d398a861c

dump 后 用 https://luadec.metaworm.site/在线反编译

-- filename: 
-- version: lua53
-- line: [0, 0] id: 0
menu = function()
  -- line: [2, 12] id: 1
  print("-------------------Pictrue Store System-------------------")
  print("1. upload")
  print("2. download")
  print("3. delete")
  print("4. list")
  print("5. check")
  print("6. exit")
  io.write("choice>> ")
end
upload_impl = function()
  -- line: [14, 21] id: 2
  local r0_2 = a_f3_9a7nhRC()
  if r0_2 ~= nil then
    io.write("img data: ")
    a_1sV7zC5yL_(r0_2)
  end
end
download_impl = function()
  -- line: [23, 31] id: 3
  io.write("link: ")
  local r0_3 = io.read("*number")
  if a_IjKn_GF3FE(r0_3) == 1 then
    io.write("img data: ")
    a_TUBSK2FAhN(r0_3)
  end
end
delete_impl = function()
  -- line: [33, 41] id: 4
  io.write("link: ")
  if a_8jzNK8OZ4i(io.read("*number")) == 0 then
    print("error")
  end
end
list_impl = function()
  -- line: [43, 57] id: 5
  print("-------------------img list-------------------")
  local r0_5 = 0
  local r1_5 = 1
  while r0_5 < 30 do
    if a_IjKn_GF3FE(r0_5) == 1 then
      r1_5 = r1_5 + 1
      print(string.format("%d. pic_%04d. link: http://%d\n", r1_5, r0_5, r0_5))
    end
    r0_5 = r0_5 + 1
  end
end
check_impl = function()
  -- line: [59, 84] id: 6
  local r0_6 = 0
  local r1_6 = 0
  local r2_6 = ""
  local r3_6 = false
  while r0_6 < 30 do
    local r4_6 = a_IjKn_GF3FE(r0_6)
    if r0_6 % 2 == 0 and r4_6 == 1 then
      r1_6 = r1_6 + 1
      local r5_6 = a_Cc_ClWQsa5(r0_6)
      if #r5_6 ~= 2 then
        r3_6 = true
      end
      r2_6 = r2_6 .. r5_6
    end
    r0_6 = r0_6 + 1
  end
  if r1_6 == 15 and #r2_6 == 30 and r3_6 == false and check_func(r2_6) == true then
    print("now, you know the flag~")
    print(r2_6)
  else
    print("you fail!")
  end
end
main_logic = function()
  -- line: [86, 108] id: 7
  while true do
    menu()
    local r0_7 = io.read("*l")
    if r0_7 == "1" then
      upload_impl()
    elseif r0_7 == "2" then
      download_impl()
    elseif r0_7 == "3" then
      delete_impl()
    elseif r0_7 == "4" then
      list_impl()
    elseif r0_7 == "5" then
      check_impl()
    elseif r0_7 == "6" then
      print("bye~")
      break
    else
      print("bad choice")
    end
  end
end
value_list = function(r0_8)
  -- line: [111, 118] id: 8
  local r1_8 = {}
  for r5_8 = 1, string.len(r0_8), 1 do
    r1_8[#r1_8 + 1] = string.byte(r0_8, r5_8)
  end
  return r1_8
end
tobinary = function(r0_9)
  -- line: [122, 135] id: 9
  local r1_9 = r0_9
  local r2_9 = ""
  repeat
    if r1_9 % 2 == 1 then
      local r3_9 = r2_9
      r2_9 = r3_9 .. "1"
    else
      local r3_9 = r2_9
      r2_9 = r3_9 .. "0"
    end
    local r3_9 = math.modf(r1_9 / 2)
    r1_9 = r3_9
  until r1_9 == 0
  return string.reverse(r2_9)
end
xor = function(r0_10, r1_10)
  -- line: [137, 170] id: 10
  local r2_10 = tobinary(r0_10)
  local r3_10 = tobinary(r1_10)
  local r4_10 = string.len(r2_10)
  local r5_10 = string.len(r3_10)
  local r6_10 = 0
  local r7_10 = 0
  local r8_10 = ""
  if r5_10 < r4_10 then
    for r12_10 = 1, math.floor(r4_10 - r5_10), 1 do
      r3_10 = "0" .. r3_10
    end
    r6_10 = r4_10
  elseif r4_10 < r5_10 then
    for r12_10 = 1, math.floor(r5_10 - r4_10), 1 do
      r2_10 = "0" .. r2_10
    end
    r6_10 = r5_10
  end
  for r12_10 = 1, r6_10, 1 do
    if string.sub(r2_10, r12_10, r12_10) == string.sub(r3_10, r12_10, r12_10) then
      r8_10 = r8_10 .. "0"
    else
      r8_10 = r8_10 .. "1"
    end
  end
  return tonumber(r8_10, 2)
end
check_func = function(r0_11)
  -- line: [172, 195] id: 11
  local input = value_list(r0_11)
  local r2_11 = {}
  local ans = {
    105,
    244,
    63,
    10,
    24,
    169,
    248,
    107,
    129,
    138,
    25,
    182,
    96,
    176,
    14,
    89,
    56,
    229,
    206,
    19,
    23,
    21,
    22,
    198,
    179,
    167,
    152,
    66,
    28,
    201,
    213,
    80,
    162,
    151,
    102,
    36,
    91,
    37,
    50,
    17,
    170,
    41,
    3,
    84,
    85,
    226,
    131,
    38,
    71,
    32,
    18,
    142,
    70,
    39,
    112,
    220,
    16,
    219,
    159,
    222,
    11,
    119,
    99,
    203,
    47,
    148,
    185,
    55,
    93,
    48,
    153,
    113,
    1,
    237,
    35,
    75,
    67,
    155,
    161,
    74,
    108,
    76,
    181,
    233,
    186,
    44,
    125,
    232,
    88,
    8,
    95,
    163,
    200,
    249,
    120,
    243,
    174,
    212,
    252,
    234,
    58,
    101,
    228,
    86,
    109,
    144,
    104,
    121,
    117,
    87,
    15,
    132,
    12,
    20,
    165,
    115,
    136,
    135,
    118,
    69,
    68,
    2,
    82,
    123,
    250,
    251,
    53,
    255,
    51,
    221,
    211,
    195,
    145,
    140,
    254,
    0,
    116,
    43,
    29,
    217,
    197,
    183,
    168,
    188,
    34,
    218,
    146,
    147,
    98,
    149,
    246,
    180,
    103,
    33,
    40,
    207,
    208,
    192,
    143,
    26,
    154,
    225,
    100,
    141,
    175,
    124,
    230,
    62,
    177,
    205,
    110,
    202,
    253,
    173,
    46,
    52,
    114,
    164,
    166,
    137,
    158,
    122,
    13,
    83,
    178,
    133,
    189,
    187,
    7,
    184,
    77,
    245,
    216,
    190,
    194,
    72,
    157,
    172,
    171,
    199,
    160,
    45,
    49,
    27,
    204,
    81,
    6,
    92,
    59,
    209,
    239,
    130,
    97,
    61,
    214,
    215,
    73,
    90,
    126,
    42,
    30,
    240,
    79,
    224,
    78,
    223,
    111,
    60,
    4,
    5,
    196,
    231,
    106,
    64,
    139,
    235,
    150,
    227,
    238,
    191,
    127,
    31,
    156,
    54,
    241,
    242,
    134,
    247,
    128,
    65,
    94,
    57,
    210,
    236,
    9,
    193
  }
  for i = 1, #input, 1 do
    input[i] = xor(input[i], i - 1)
    input[i] = xor(input[i], 255)
    input[i] = input[i] & 255
    r2_11[#r2_11 + 1] = ans[input[i] + 1]
  end
  local r4_11 = a_AHy3JniQH4(r2_11) == 1
end
main = function()
  -- line: [198, 201] id: 12
  a_bfBfrMZriK()
  main_logic()
end
main()

注意到是调用了check_23，并且这之前还有个简单加密

from z3 import Int, Solver
l = 30
a1 = [Int(f"x{i}") for i in range(l)]
s = Solver()
v1=a1[0]
v2=a1[1]
v3=a1[2]
v4=a1[3]
v5=a1[4]
v6=a1[5]
v7=a1[6]
v8=a1[7]
v10=a1[8]
v24=a1[9]
v25=a1[10]
v26=a1[11]
v27=a1[12]
v28=a1[13]
v29=a1[14]
v30=a1[15]
v31=a1[16]
v32=a1[17]
v33=a1[18]
v34=a1[19]
v35=a1[20]
v36=a1[21]
v37=a1[22]
v38=a1[23]
v39=a1[24]
v40=a1[25]
v20=a1[26]
v41=a1[27]
v22=a1[28]
s.add(255036*v7+-90989*v3+-201344*v4+122006*v5+-140538*v6+109859*v2-109457*v1-9396023 == 0)
s.add(277432*v6+110191*v3+-186022*v4+175123*v2-75564*v5-252340*v1-12226612 == 0)
s.add(127326*v4+260948*v2+-102835*v1+225038*v5-129683*v3-45564209 == 0)
s.add(-170345*v2+217412*v3-26668*v1+38500*v4-27440782 == 0)
s.add(25295*v2+69369*v3+191287*v1-24434293 == 0)
s.add(72265*v1-2384745 == 0)
s.add(264694*v1-190137*v2+19025100 == 0)
s.add(101752*v24+67154*v8+-20311*v1+-30496*v6+-263329*v7+-99420*v10+255348*v3+169511*v4-121471*v2+231370*v5-33888892 == 0)
s.add(17253*v8+-134891*v7+144501*v4+220594*v2+263746*v3+122495*v6+74297*v10+205480*v1-32973*v5-115484799 == 0)
s.add(251337*v3+-198187*v6+-217900*v2+-62192*v8+-138306*v7+-165151*v4-118227*v1-22431*v5+72699617 == 0)
s.add(243012*v27+-233931*v4+66595*v7+-273948*v5+-266708*v24+75344*v8-108115*v3-17090*v25+240281*v10+202327*v1-253495*v2+233118*v26+154680*v6+25687761 == 0)
s.add(41011*v8+-198187*v1+-117171*v7+-178912*v3+9797*v24+118730*v10-193364*v5-36072*v6+10586*v25-110560*v4+173438*v2-176575*v26+54358815 == 0)
s.add(-250878*v24+108430*v1+-136296*v5+11092*v8+154243*v7+-136624*v3+179711*v4+-128439*v6+22681*v25-42472*v10-80061*v2+34267161 == 0)
s.add(65716*v30+-18037*v26+-42923*v7+-33361*v4+161566*v6+194069*v25+-154262*v2+173240*v3-31821*v27-80881*v5+217299*v8-28162*v10+192716*v1+165565*v24+106863*v29-127658*v28-75839517 == 0)
s.add(-236487*v24+-45384*v1+46984*v26+148196*v7+15692*v8+-193664*v6+6957*v10+103351*v29-217098*v28+78149*v4-237596*v5-236117*v3-142713*v25+24413*v27+232544*v2+78860648 == 0)
s.add(-69129*v10+-161882*v3+-39324*v26+106850*v1+136394*v5+129891*v2+15216*v27+213245*v24-73770*v28+24056*v25-123372*v8-38733*v7-199547*v4-10681*v6+57424065 == 0)
s.add(-268870*v30+103546*v24+-124986*v27+42015*v7+80222*v2+-77247*v10+-8838*v25+-273842*v4+-240751*v28-187146*v26-150301*v6-167844*v3+92327*v8+270212*v5-87705*v33-216624*v1+35317*v31+231278*v32-213030*v29+114317949 == 0)
s.add(-207225*v1+-202035*v3+81860*v27+-114137*v5+265497*v30+-216722*v8+276415*v28+-201420*v10-266588*v32+174412*v6+249222*v24-191870*v4+100486*v2+37951*v25+67406*v26+55224*v31+101345*v7-76961*v29+33370551 == 0)
s.add(175180*v29+25590*v4+-35354*v30+-173039*v31+145220*v25+6521*v7+99204*v24+72076*v27+207349*v2+123988*v5-64247*v8+169099*v6-54799*v3+53935*v1-223317*v26+215925*v10-119961*v28-83559622 == 0)
s.add(43170*v3+-145060*v2+199653*v6+14728*v30+139827*v24+59597*v29+2862*v10+-171413*v31+-15355*v25-71692*v7-16706*v26+264615*v1-149167*v33+75391*v27-2927*v4-187387*v5-190782*v8-150865*v28+44238*v32-276353*v34+82818982 == 0)
s.add(-3256*v27+-232013*v25+-261919*v29+-151844*v26+11405*v4+159913*v32+209002*v7+91932*v34+270180*v10+-195866*v3-135274*v33-261245*v1+24783*v35+262729*v8-81293*v24-156714*v2-93376*v28-163223*v31-144746*v5+167939*v6-120753*v30-13188886 == 0)
s.add(-240655*v35+103437*v30+236610*v27+100948*v8+82212*v6+-60676*v5+-71032*v3+259181*v7+100184*v10+7797*v29+143350*v24+76697*v2-172373*v25-110023*v37-13673*v4+129100*v31+86759*v1-101103*v33-142195*v36+28466*v32-27211*v26-269662*v34+9103*v28-96428951 == 0)
s.add(-92750*v28+-151740*v27+15816*v35+186592*v24+-156340*v29+-193697*v2+-108622*v8+-163956*v5+78044*v4+-280132*v36-73939*v33-216186*v3+168898*v30+81148*v34-200942*v32+1920*v1+131017*v26-229175*v10-247717*v31+232852*v25+25882*v7+144500*v6+175681562 == 0)
s.add(234452*v34+-23111*v29+-40957*v2+-147076*v8+16151*v32+-250947*v35+-111913*v30+-233475*v24+-2485*v28+207006*v26+71474*v3+78521*v1-37235*v36+203147*v5+159297*v7-227257*v38+141894*v25-238939*v10-207324*v37-168960*v33+212325*v6+152097*v31-94775*v27+197514*v4+62343322 == 0)
s.add(-142909*v34+-111865*v31+258666*v36+-66780*v2+-13109*v35+-72310*v25+-278193*v26+-219709*v24+40855*v8+-270578*v38+96496*v5+-4530*v1+63129*v28-4681*v7-272799*v30-225257*v10+128712*v37-201687*v39+273784*v3+141128*v29+93283*v32+128210*v33+47550*v6-84027*v4+52764*v40-140487*v27+105279220 == 0)
s.add(216020*v38+-248561*v29+-86516*v33+237852*v26+-132193*v31+-101471*v3+87552*v25+-122710*v8+234681*v5+-24880*v7+-245370*v1+-17836*v36-225714*v34-256029*v4+171199*v35+266838*v10-32125*v24-43141*v32-87051*v30-68893*v39-242483*v28-12823*v2-159262*v27+123816*v37-180694*v6+152819799 == 0)
s.add(-116890*v3+67983*v27+-131934*v4+256114*v40+128119*v24+48593*v33+-41706*v2+-217503*v26+49328*v6+223466*v7+-31184*v5+-208422*v36+261920*v1+83055*v20+115813*v37+174499*v29-188513*v35+18957*v25+15794*v10-2906*v28-25315*v8+232180*v32-102442*v39-116930*v34-192552*v38-179822*v31+265749*v30-54143007 == 0)
s.add(-215996*v4+-100890*v40+-177349*v7+-159264*v6+-227328*v27+-91901*v24+-28939*v10+206392*v41+6473*v25+-22051*v20+-112044*v34+-119414*v30+-225267*v35+223380*v3+275172*v5+95718*v39-115127*v29+85928*v26+169057*v38-204729*v1+178788*v36-85503*v31-121684*v2-18727*v32+109947*v33-138204*v8-245035*v28+134266*v37+110228962 == 0)
s.add(-165644*v32+4586*v39+138195*v25+155259*v35+-185091*v3+-63869*v31+-23462*v30+150939*v41+-217079*v8+-122286*v6+5460*v38+-235719*v7+270987*v26+157806*v34+262004*v29-2963*v28-159217*v10+266021*v33-190702*v24-38473*v20+122617*v2+202211*v36-143491*v27-251332*v4+196932*v5-155172*v22+209759*v40-146511*v1+62542*v37+185928391 == 0)
s.add(57177*v24+242367*v39+226332*v31+15582*v26+159461*v34+-260455*v22+-179161*v37+-251786*v32+-66932*v41+134581*v1+-65235*v29+-110258*v28+188353*v38+-108556*v6+178750*v40+-20482*v25+127145*v8+-203851*v5+-263419*v10+245204*v33+-62740*v20+103075*v2-229292*v36+142850*v30-1027*v27+264120*v3+264348*v4-41667*v35+130195*v7+127279*a1[29]-51967523 == 0)


print(s.check())
m = s.model()

result = []
for i in a1:
    result.append(m[i].as_long())
print(result)

ans = [105,244,63,10,24,169,248,107,129,138,25,182,96,176,14,89,56,229,206,19,23,21,22,198,179,167,152,66,28,201,213,80,162,151,102,36,91,37,50,17,170,41,3,84,85,226,131,38,71,32,18,142,70,39,112,220,16,219,159,222,11,119,99,203,47,148,185,55,93,48,153,113,1,237,35,75,67,155,161,74,108,76,181,233,186,44,125,232,88,8,95,163,200,249,120,243,174,212,252,234,58,101,228,86,109,144,104,121,117,87,15,132,12,20,165,115,136,135,118,69,68,2,82,123,250,251,53,255,51,221,211,195,145,140,254,0,116,43,29,217,197,183,168,188,34,218,146,147,98,149,246,180,103,33,40,207,208,192,143,26,154,225,100,141,175,124,230,62,177,205,110,202,253,173,46,52,114,164,166,137,158,122,13,83,178,133,189,187,7,184,77,245,216,190,194,72,157,172,171,199,160,45,49,27,204,81,6,92,59,209,239,130,97,61,214,215,73,90,126,42,30,240,79,224,78,223,111,60,4,5,196,231,106,64,139,235,150,227,238,191,127,31,156,54,241,242,134,247,128,65,94,57,210,236,9,193]

for i in range(l):
    t = ans.index(result[i])
    print(chr(t ^ 0xff ^ i), end='')
# flag{U_90t_th3_p1c5t0re_fl49!}

主要是要注意下不能用BitVec，可能是因为有负数的运算吧。

RTTT

发现一个异或，出来结果是 Welc0me to RCTF 2O22
然后硬件断点一路跟下去，发现生成RC4的S盒。
然后拿到KeyStream（我的keystream是加密了'f'的结果）
然后对着结果硬件断点，发现一个strcmp。
不过我发现解出来后顺序不对，应该是有个树的遍历（看着比较像）
于是我弄了一个唯一确定的字符序列，用来获取SBox。

keystream = bytes.fromhex("""
11 93 47 0F 85 91 E1 FE  0C 8E 4D F8 6F 8A 87 CC
A4 7C 70 1B 09 96 30 26  5D 30 39 5E 43 BD 0F 81
09 74 B0 F4 4E 0B 90 63  48 11
""")
ans = bytes.fromhex("""
34 C2 65 2D DA C6 B1 AD  47 BA 06 A9 3B C1 CC D7
F1 29 24 39 2A C0 15 02  7E 10 66 7B 5E EA 5E D0
59 46 E1 D6 6E 5E B2 46  6B 31""")

k = [ans[i] ^ keystream[i] ^ ord('f') for i in range(len(keystream))]
t = "".join(map(chr, k))
print(k)
# generate SBOx
a = "yJzLkHwDxaCAtnsPipmIBfhljdGbeOqKNcEMugvFor"
b = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOP"
sbox = [a.index(b[i]) for i in range(len(a))]
for i in range(len(t)):
    print(t[sbox[i]], end='') # RCTF{03C3E9B2-E37F-2FD6-CD7E-57C91D77DD61}

CheckYourKey

RegisterNatives -> True Function -> AES -> B58Encode(table1) -> B64Encode(table2) -> Strcmp

web_run

JEB 反编译，找到main函数

SEED = (202211110054 - 1) & 0xffffffff
def _f7():
    global SEED
    v0 = SEED * 6364136223846793005 + 1
    SEED = v0
    return (v0 >> 33) % 16


def _f8(par):
    if par >= 0 and par <= 9:
        return 48 + par
    val = par - 10 
    if val == 0:
        return 97
    elif val == 1:
        return 98
    elif val == 2:
        return 99
    elif val == 3:
        return 100
    elif val == 4:
        return 101
    elif val == 5:
        return 102
    return 48


def generate(s):
    for i in range(len(s)):
        if not (s[i] != 52 and s[i] != 45):
            continue
        if s[i] == 120:
            v2 = _f8(_f7())
            s[i] = v2
        else:
            v2 = _f8((_f7() & 3) | 0x8)
            s[i] = v2 
    return bytes(s)


A = generate(list(b'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'))
print(f"RCTF{{{A.decode()}}}")
# RCTF{40959ea7-26e0-4c9d-8f4a-62faf14ff392}