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services/phew/Dockerfile

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+FROM python:3.12-slim
+
+ARG PASSWORD=root
+ENV DEBIAN_FRONTEND=noninteractive
+ENV HOME=/home/ctf
+WORKDIR /home/ctf/chall
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    openssh-server \
+    build-essential \
+    libffi-dev \
+    libssl-dev \
+    python3-dev \
+    bash \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN useradd -m -d /home/ctf -s /bin/bash ctf && \
+    echo "ctf:${PASSWORD}" | chpasswd
+
+RUN mkdir -p /var/run/sshd
+
+COPY requirements.txt /tmp/requirements.txt
+RUN pip install --no-cache-dir -r /tmp/requirements.txt
+
+COPY ./src /home/ctf/chall/src
+COPY ./start.sh /start.sh
+RUN chmod +x /start.sh /home/ctf/chall/src/run.sh
+
+RUN chown -R root:root /home/ctf/chall && chmod -R 555 /home/ctf/chall
+
+EXPOSE 8000 22
+CMD ["/start.sh"]

services/phew/chall.py

@@ -0,0 +1,126 @@
+#!/usr/bin/env python3
+
+import os, sys, json, random, hashlib, hmac
+from Crypto.Cipher import AES
+from Crypto.Util.Padding import pad
+with open("/flag.txt", "rb") as f:
+    flag = f.read()
+
+menu = (
+    "1) encrypt\n"
+    "2) profit\n"
+    "3) nyerah\n"
+    ">> "
+)
+
+
+k = 1024  
+n = 169
+
+rng = random.SystemRandom()
+
+def rand(k_bits: int) -> int:
+    return rng.randrange(1, 1 << k_bits)
+
+def gen(n: int, k_bits: int):
+    a = [rand(k_bits) for _ in range(n)]
+    return a
+
+def b2b(b: bytes) -> list[int]:
+    out = []
+    for byte in b:
+        for i in range(8):
+            out.append((byte >> i) & 1)
+    return out
+
+def pack(bits) -> bytes:
+    out = bytearray()
+    for i in range(0, len(bits), 8):
+        chunk = bits[i:i+8]
+        val = 0
+        for j, bit in enumerate(chunk):
+            val |= (bit & 1) << j
+        out.append(val)
+    return bytes(out)
+
+def gen_key(x_bits: list[int], saltx: bytes, salty: bytes, length: int = 16) -> bytes:
+    material = pack(x_bits)
+    prk = hashlib.pbkdf2_hmac("sha256", material, saltx, 131072, dklen=32)
+    return hmac.new(prk, b"afk-players-wanted-now" + salty + b"\x01", hashlib.sha256).digest()[:length]
+
+def enc(k: bytes, data: bytes):
+    iv = os.urandom(16)
+    ct = AES.new(k, AES.MODE_CBC, iv).encrypt(pad(data, 16))
+    return iv, ct
+
+def add(a, x_bits) -> int:
+    return sum(ai for ai, xi in zip(a, x_bits) if xi)
+
+def main():
+    a = gen(n, k)
+    x_bits = b2b(flag)
+    if len(x_bits) < n:
+        x_bits += [rng.randrange(0, 2) for _ in range(n - len(x_bits))]
+    else:
+        x_bits = x_bits[:n]
+
+    s = add(a, x_bits)
+
+    saltx = os.urandom(16)
+    salty = os.urandom(16)
+    key = gen_key(x_bits, saltx, salty)
+
+    iv, ct = enc(key, flag)
+
+    header = {
+        "n": n,
+        "k_bits": k,
+    }
+    print(json.dumps(header, separators=(",", ":")), flush=True)
+
+    while True:
+        try:
+            print(menu, end="", flush=True)
+            line = sys.stdin.readline()
+            if not line:
+                break
+            try:
+                choice = int(line.strip())
+            except ValueError:
+                print("sheesh")
+                continue
+
+            if choice == 1:
+                print("data: ", end="", flush=True)
+                dline = sys.stdin.readline()
+                if not dline:
+                    break
+                try:
+                    data = bytes.fromhex(dline.strip())
+                except Exception:
+                    print("hmmm")
+                    continue
+                iv, ct = enc(key, data)
+                print(iv.hex())
+                print(ct.hex())
+
+            elif choice == 2:
+                print(json.dumps({"a": a}, separators=(",", ":")))
+                print(str(s))
+                print(saltx.hex())
+                print(salty.hex())
+                print(iv.hex())
+                print(ct.hex())
+
+            elif choice == 3:
+                print("bubay")
+                return
+
+            else:
+                print("tidak ada yang mustahil, hehehe")
+
+        except Exception:
+            print("zzz")
+
+if __name__ == "__main__":
+    main()

services/phew/dist/chall.py

@@ -0,0 +1,126 @@
+#!/usr/bin/env python3
+
+import os, sys, json, random, hashlib, hmac
+from Crypto.Cipher import AES
+from Crypto.Util.Padding import pad
+with open("/flag.txt", "rb") as f:
+    flag = f.read()
+
+menu = (
+    "1) encrypt\n"
+    "2) profit\n"
+    "3) nyerah\n"
+    ">> "
+)
+
+
+k = 1024  
+n = 169
+
+rng = random.SystemRandom()
+
+def rand(k_bits: int) -> int:
+    return rng.randrange(1, 1 << k_bits)
+
+def gen(n: int, k_bits: int):
+    a = [rand(k_bits) for _ in range(n)]
+    return a
+
+def b2b(b: bytes) -> list[int]:
+    out = []
+    for byte in b:
+        for i in range(8):
+            out.append((byte >> i) & 1)
+    return out
+
+def pack(bits) -> bytes:
+    out = bytearray()
+    for i in range(0, len(bits), 8):
+        chunk = bits[i:i+8]
+        val = 0
+        for j, bit in enumerate(chunk):
+            val |= (bit & 1) << j
+        out.append(val)
+    return bytes(out)
+
+def gen_key(x_bits: list[int], saltx: bytes, salty: bytes, length: int = 16) -> bytes:
+    material = pack(x_bits)
+    prk = hashlib.pbkdf2_hmac("sha256", material, saltx, 131072, dklen=32)
+    return hmac.new(prk, b"afk-players-wanted-now" + salty + b"\x01", hashlib.sha256).digest()[:length]
+
+def enc(k: bytes, data: bytes):
+    iv = os.urandom(16)
+    ct = AES.new(k, AES.MODE_CBC, iv).encrypt(pad(data, 16))
+    return iv, ct
+
+def add(a, x_bits) -> int:
+    return sum(ai for ai, xi in zip(a, x_bits) if xi)
+
+def main():
+    a = gen(n, k)
+    x_bits = b2b(flag)
+    if len(x_bits) < n:
+        x_bits += [rng.randrange(0, 2) for _ in range(n - len(x_bits))]
+    else:
+        x_bits = x_bits[:n]
+
+    s = add(a, x_bits)
+
+    saltx = os.urandom(16)
+    salty = os.urandom(16)
+    key = gen_key(x_bits, saltx, salty)
+
+    iv, ct = enc(key, flag)
+
+    header = {
+        "n": n,
+        "k_bits": k,
+    }
+    print(json.dumps(header, separators=(",", ":")), flush=True)
+
+    while True:
+        try:
+            print(menu, end="", flush=True)
+            line = sys.stdin.readline()
+            if not line:
+                break
+            try:
+                choice = int(line.strip())
+            except ValueError:
+                print("sheesh")
+                continue
+
+            if choice == 1:
+                print("data: ", end="", flush=True)
+                dline = sys.stdin.readline()
+                if not dline:
+                    break
+                try:
+                    data = bytes.fromhex(dline.strip())
+                except Exception:
+                    print("hmmm")
+                    continue
+                iv, ct = enc(key, data)
+                print(iv.hex())
+                print(ct.hex())
+
+            elif choice == 2:
+                print(json.dumps({"a": a}, separators=(",", ":")))
+                print(str(s))
+                print(saltx.hex())
+                print(salty.hex())
+                print(iv.hex())
+                print(ct.hex())
+
+            elif choice == 3:
+                print("bubay")
+                return
+
+            else:
+                print("tidak ada yang mustahil, hehehe")
+
+        except Exception:
+            print("zzz")
+
+if __name__ == "__main__":
+    main()

services/phew/docker-compose.yml

@@ -0,0 +1,16 @@
+version: "3.8"
+
+services:
+  phew:
+    container_name: phew_container
+    hostname: phew
+    restart: always
+    build:
+      context: .
+      args:
+        - PASSWORD=root
+    ports:
+      - "13000:8000"
+      - "13022:22"
+    environment:
+      - FLAG=GEMASTIK{local_flag}

services/phew/requirements.txt

@@ -0,0 +1 @@
+pycryptodome

services/phew/run.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+exec socat tcp-l:8000,reuseaddr,fork exec:"python3 ./chall.py"

services/phew/start.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+set -e
+
+ssh-keygen -A
+
+# Configure SSH
+grep -q "^PermitRootLogin" /etc/ssh/sshd_config && \
+  sed -i "s/^PermitRootLogin.*/PermitRootLogin no/" /etc/ssh/sshd_config || \
+  echo "PermitRootLogin no" >> /etc/ssh/sshd_config
+
+grep -q "^PasswordAuthentication" /etc/ssh/sshd_config && \
+  sed -i "s/^PasswordAuthentication.*/PasswordAuthentication yes/" /etc/ssh/sshd_config || \
+  echo "PasswordAuthentication yes" >> /etc/ssh/sshd_config
+
+echo "AllowUsers ctf" >> /etc/ssh/sshd_config
+
+/usr/sbin/sshd
+
+if [ -n "$FLAG" ]; then
+    echo "$FLAG" > /flag.txt
+    chmod 644 /flag.txt
+    chown root:root /flag.txt
+fi
+
+exec su -c "cd /home/ctf/chall/src && ./run.sh" -s /bin/bash ctf

services/sheesh/Dockerfile

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+FROM python:3.12-slim
+
+ARG PASSWORD=root
+ENV DEBIAN_FRONTEND=noninteractive
+ENV HOME=/home/ctf
+WORKDIR /home/ctf/chall
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    openssh-server \
+    build-essential \
+    libffi-dev \
+    libssl-dev \
+    python3-dev \
+    bash \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN useradd -m -d /home/ctf -s /bin/bash ctf && \
+    echo "ctf:${PASSWORD}" | chpasswd
+
+RUN mkdir -p /var/run/sshd
+
+COPY requirements.txt /tmp/requirements.txt
+RUN pip install --no-cache-dir -r /tmp/requirements.txt
+
+COPY ./src /home/ctf/chall/src
+COPY ./start.sh /start.sh
+RUN chmod +x /start.sh /home/ctf/chall/src/run.sh
+
+RUN chown -R root:root /home/ctf/chall && chmod -R 555 /home/ctf/chall
+
+EXPOSE 8000 22
+CMD ["/start.sh"]

services/sheesh/chall.py

@@ -0,0 +1,116 @@
+#!/usr/bin/env python3
+
+import os, sys, json, random, hashlib, hmac
+from Crypto.Cipher import AES
+from Crypto.Util.Padding import pad
+with open("/flag.txt", "rb") as f:
+    flag = f.read()
+    
+B = 16
+opts = (
+    "1) encrypt\n"
+    "2) profit\n"
+    "3) nyerah\n"
+    ">> "
+)
+
+def exp(prk: bytes, info: bytes, L: int) -> bytes:
+    return hmac.new(prk, info + b"\x01", hashlib.sha256).digest()[:L]
+
+def enc(k: bytes, data: bytes):
+    iv = os.urandom(B)
+    ct = AES.new(k, AES.MODE_CBC, iv).encrypt(pad(data, B))
+    return iv, ct
+
+def inp_hex(prompt: str) -> bytes:
+    print(prompt, end="", flush=True)
+    s = sys.stdin.readline()
+    if not s:
+        raise EOFError
+    return bytes.fromhex(s.strip())
+
+def rand(rng, d, lo, hi):
+    while True:
+        v = [rng.randint(lo, hi) for _ in range(d)]
+        if any(v):
+            return v
+
+def syst(rng):
+    d = rng.choice([2, 3])
+    m = rng.randint(5, 8)
+    x = rand(rng, d, -3, 3)
+    rows = []
+    for _ in range(m):
+        base = rand(rng, d, -3, 3)
+        r = rng.randint(1, 7)
+        scaled = [r * a for a in base]
+        e = rng.randint(0, 1)
+        bi = sum(ai * xi for ai, xi in zip(scaled, x)) + e
+        rows.append((scaled, bi))
+    rng.shuffle(rows)
+    A = [row for (row, _) in rows]
+    B = [b for (_, b) in rows]
+    pub = {"dim": d, "A": A, "b": B}
+    return pub, tuple(x)
+
+def bundle():
+    rng = random.Random(os.urandom(16))
+    systems = []
+    hidden = []
+    for _ in range(4):
+        pub, x = syst(rng)
+        systems.append(pub)
+        hidden.append(x)
+    return {"systems": systems}, tuple(hidden)
+
+def get_key(saltx: bytes, salty: bytes, b):
+    parts = []
+    for x in b:
+        parts.append(",".join(str(t) for t in x))
+    material = "|".join(parts).encode()
+    prk = hashlib.pbkdf2_hmac("sha256", material, saltx, 131072, dklen=32)
+    return exp(prk, b"g3m4zzzt1q" + salty, 16)
+
+def main():
+    a, b = bundle()
+    print(json.dumps(a, separators=(",", ":")), flush=True)
+    saltx = os.urandom(16)
+    salty   = os.urandom(16)
+    key = get_key(saltx, salty, b)
+    iv, ct = enc(key, flag)
+    while True:
+        try:
+            print(opts, end="", flush=True)
+            line = sys.stdin.readline()
+            if not line:
+                break
+            try:
+                choice = int(line.strip())
+            except ValueError:
+                print("sheesh")
+                continue
+
+            if choice == 1:
+                data = inp_hex("data: ")
+                iv, ct = enc(key, data)
+                print(iv.hex())
+                print(ct.hex())
+
+            elif choice == 2:
+                print(iv.hex())
+                print(ct.hex())
+                print(saltx.hex())
+                print(salty.hex())
+
+            elif choice == 3:
+                print("bubay")
+                return
+
+            else:
+                print("when you feel like quitting, remember why you started :v (yapping)")
+
+        except Exception:
+            print("zzz")
+
+if __name__ == "__main__":
+    main()

services/sheesh/dist/chall.py

@@ -0,0 +1,116 @@
+#!/usr/bin/env python3
+
+import os, sys, json, random, hashlib, hmac
+from Crypto.Cipher import AES
+from Crypto.Util.Padding import pad
+with open("/flag.txt", "rb") as f:
+    flag = f.read()
+    
+B = 16
+opts = (
+    "1) encrypt\n"
+    "2) profit\n"
+    "3) nyerah\n"
+    ">> "
+)
+
+def exp(prk: bytes, info: bytes, L: int) -> bytes:
+    return hmac.new(prk, info + b"\x01", hashlib.sha256).digest()[:L]
+
+def enc(k: bytes, data: bytes):
+    iv = os.urandom(B)
+    ct = AES.new(k, AES.MODE_CBC, iv).encrypt(pad(data, B))
+    return iv, ct
+
+def inp_hex(prompt: str) -> bytes:
+    print(prompt, end="", flush=True)
+    s = sys.stdin.readline()
+    if not s:
+        raise EOFError
+    return bytes.fromhex(s.strip())
+
+def rand(rng, d, lo, hi):
+    while True:
+        v = [rng.randint(lo, hi) for _ in range(d)]
+        if any(v):
+            return v
+
+def syst(rng):
+    d = rng.choice([2, 3])
+    m = rng.randint(5, 8)
+    x = rand(rng, d, -3, 3)
+    rows = []
+    for _ in range(m):
+        base = rand(rng, d, -3, 3)
+        r = rng.randint(1, 7)
+        scaled = [r * a for a in base]
+        e = rng.randint(0, 1)
+        bi = sum(ai * xi for ai, xi in zip(scaled, x)) + e
+        rows.append((scaled, bi))
+    rng.shuffle(rows)
+    A = [row for (row, _) in rows]
+    B = [b for (_, b) in rows]
+    pub = {"dim": d, "A": A, "b": B}
+    return pub, tuple(x)
+
+def bundle():
+    rng = random.Random(os.urandom(16))
+    systems = []
+    hidden = []
+    for _ in range(4):
+        pub, x = syst(rng)
+        systems.append(pub)
+        hidden.append(x)
+    return {"systems": systems}, tuple(hidden)
+
+def get_key(saltx: bytes, salty: bytes, b):
+    parts = []
+    for x in b:
+        parts.append(",".join(str(t) for t in x))
+    material = "|".join(parts).encode()
+    prk = hashlib.pbkdf2_hmac("sha256", material, saltx, 131072, dklen=32)
+    return exp(prk, b"g3m4zzzt1q" + salty, 16)
+
+def main():
+    a, b = bundle()
+    print(json.dumps(a, separators=(",", ":")), flush=True)
+    saltx = os.urandom(16)
+    salty   = os.urandom(16)
+    key = get_key(saltx, salty, b)
+    iv, ct = enc(key, flag)
+    while True:
+        try:
+            print(opts, end="", flush=True)
+            line = sys.stdin.readline()
+            if not line:
+                break
+            try:
+                choice = int(line.strip())
+            except ValueError:
+                print("sheesh")
+                continue
+
+            if choice == 1:
+                data = inp_hex("data: ")
+                iv, ct = enc(key, data)
+                print(iv.hex())
+                print(ct.hex())
+
+            elif choice == 2:
+                print(iv.hex())
+                print(ct.hex())
+                print(saltx.hex())
+                print(salty.hex())
+
+            elif choice == 3:
+                print("bubay")
+                return
+
+            else:
+                print("when you feel like quitting, remember why you started :v (yapping)")
+
+        except Exception:
+            print("zzz")
+
+if __name__ == "__main__":
+    main()

services/sheesh/docker-compose.yml

@@ -0,0 +1,16 @@
+version: "3.8"
+
+services:
+  sheesh:
+    container_name: sheesh_container
+    hostname: sheesh
+    restart: always
+    build:
+      context: .
+      args:
+          - PASSWORD=root
+    ports:
+      - "12000:8000"
+      - "12022:22"
+    environment:
+      - FLAG=GEMASTIK{local_flag}

services/sheesh/requirements.txt

@@ -0,0 +1 @@
+pycryptodome

services/sheesh/run.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+exec socat tcp-l:8000,reuseaddr,fork exec:"python3 ./chall.py"

services/sheesh/start.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+set -e
+
+ssh-keygen -A
+
+grep -q "^PermitRootLogin" /etc/ssh/sshd_config && \
+  sed -i "s/^PermitRootLogin.*/PermitRootLogin no/" /etc/ssh/sshd_config || \
+  echo "PermitRootLogin no" >> /etc/ssh/sshd_config
+
+grep -q "^PasswordAuthentication" /etc/ssh/sshd_config && \
+  sed -i "s/^PasswordAuthentication.*/PasswordAuthentication yes/" /etc/ssh/sshd_config || \
+  echo "PasswordAuthentication yes" >> /etc/ssh/sshd_config
+
+echo "AllowUsers ctf" >> /etc/ssh/sshd_config
+
+/usr/sbin/sshd
+
+if [ -n "$FLAG" ]; then
+    echo "$FLAG" > /flag.txt
+    chmod 644 /flag.txt
+    chown root:root /flag.txt
+fi
+
+exec su -c "cd /home/ctf/chall/src && ./run.sh" -s /bin/bash ctf