Participate SCTF 2018 Finals

Author: Qwaz

SCTF/2018 Finals/baby_tpk/sctf.tpk

@@ -0,0 +1,66 @@
+<Signature xmlns="http://www.w3.org/2000/09/xmldsig#" Id="AuthorSignature">
+<SignedInfo>
+<CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"></CanonicalizationMethod>
+<SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"></SignatureMethod>
+<Reference URI="bin%2Fsamsungctf">
+<DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"></DigestMethod>
+<DigestValue>AVoE3U9uEdfVYErXMCA0BKvaezSBXrGBDf7xbyDR5J8=</DigestValue>
+</Reference>
+<Reference URI="shared%2Fres%2Fq.png">
+<DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"></DigestMethod>
+<DigestValue>kflQSTsGWmyHMGGqiBfrptbfHi0JeDywu42nlkrKrQU=</DigestValue>
+</Reference>
+<Reference URI="tizen-manifest.xml">
+<DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"></DigestMethod>
+<DigestValue>ld9R+XTg+cb9zeCSITHwZYTSBjfpQ/XoLLokOu6NG7Q=</DigestValue>
+</Reference>
+<Reference URI="#prop">
+<Transforms>
+<Transform Algorithm="http://www.w3.org/2006/12/xml-c14n11"></Transform>
+</Transforms>
+<DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"></DigestMethod>
+<DigestValue>lpo8tUDs054eLlBQXiDPVDVKfw30ZZdtkRs1jd7H5K8=</DigestValue>
+</Reference>
+</SignedInfo>
+<SignatureValue>
+ai2gzfXywZfh8RuTm8HTgf+7TIekWIHjqUBFjr4Nfjqb0qj74i7voMLrA55tRbRpKl6kob1x7Xsh
+7StS3WRztKLvk+QRXYac9sQhnDV2NMcytqSm1BS1D+jowPXvtpsLqjigQcZpw7jJmq+e28XgxaWb
+fn2V6e+B9pkUAW0oqIo=
+</SignatureValue>
+<KeyInfo>
+<X509Data>
+<X509Certificate>
+MIICkzCCAXugAwIBAgIGAWOl+tMkMA0GCSqGSIb3DQEBBQUAMFYxGjAYBgNVBAoMEVRpemVuIEFz
+c29jaWF0aW9uMRowGAYDVQQLDBFUaXplbiBBc3NvY2lhdGlvbjEcMBoGA1UEAwwTVGl6ZW4gRGV2
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+VEYwgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJAoGBAL8yj0casDkCYrXr+TkFgYQRq8AEqLReQTCu
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+A1UdEwEB/wQCMAAwCwYDVR0PBAQDAgeAMBMGA1UdJQQMMAoGCCsGAQUFBwMDMA0GCSqGSIb3DQEB
+BQUAA4IBAQBkAXXXkw0vU/2IUA/QDPC/0vcGVJnvlm5fitGx0drKBk1sYe2qgQx7f6hXK49xiOPK
+b80V1oIBRlfdwvmyFPes4PTBHZeLaHgAETLX077bgOXrba0gqsYd7z72msTi1+wTxrCqhUrqKIn6
+gp9r9Qm8m1iSXd6dtHo/4pXJUZ3p7rqUBucXKSNs+nNCSmL4p67/wrdNJSUaGHuKzImOuDdXG3x/
+CVsinsCcw2Ns3dg4kZpgdHfJGfgkr2oxZ+Hdutr7OqLGZXg2eGOaFKOtNaHzClZf8jyZIoxl5AmW
+HUnM6nu9onEzddLEcivsmGV7bWfSO8iIhfDDDp1T1ZkHmo1z
+</X509Certificate>
+<X509Certificate>
+MIIDOTCCAiGgAwIBAgIBATANBgkqhkiG9w0BAQUFADBYMRowGAYDVQQKDBFUaXplbiBBc3NvY2lh
+dGlvbjEaMBgGA1UECwwRVGl6ZW4gQXNzb2NpYXRpb24xHjAcBgNVBAMMFVRpemVuIERldmVsb3Bl
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+jIEhV8wbFRQpliobc7J4dSTKhFfrqGM8rdd54LYhD7gSI1CFSe16pUXfcVR7FhJztRaiGLnCrwBE
+dyTZ248+D4L/qR/D0axb3jcCAwEAAaMQMA4wDAYDVR0TBAUwAwEB/zANBgkqhkiG9w0BAQUFAAOC
+AQEAnOXXQ/1O/QTDHyrmQDtFziqPY3xWlJBqJtEqXiT7Y+Ljpe66e+Ee/OjQMlZe8gu21/8cKklH
+95RxjopMWCVedXDUbWdvS2+CdyvVW/quT2E0tjqIzXDekUTYwwhlPWlGxvfj3VsxqSFq3p8Brl04
+1Gx5RKAGyKVsMfTLhbbwSWwApuBUxYfcNpKwLWGPXkysu+HctY03OKv4/xKBnVWiN8ex/Sgesi0M
++OBAOMdZMPK32uJBTeKFx1xZgTLIhk45V0hPOomPjZloiv0LSS11eyd451ufjW0iHRE7WlpR6EvI
+W6TFyZgMpQq+kg4hWl2SBTf3s2VI8Ygz7gj8TMlClg==
+</X509Certificate>
+</X509Data>
+</KeyInfo>
+<Object Id="prop"><SignatureProperties xmlns:dsp="http://www.w3.org/2009/xmldsig-properties"><SignatureProperty Id="profile" Target="#AuthorSignature"><dsp:Profile URI="http://www.w3.org/ns/widgets-digsig#profile"></dsp:Profile></SignatureProperty><SignatureProperty Id="role" Target="#AuthorSignature"><dsp:Role URI="http://www.w3.org/ns/widgets-digsig#role-author"></dsp:Role></SignatureProperty><SignatureProperty Id="identifier" Target="#AuthorSignature"><dsp:Identifier></dsp:Identifier></SignatureProperty></SignatureProperties></Object>
+</Signature>

SCTF/2018 Finals/baby_tpk/sctf/author-signature.xml

@@ -0,0 +1,68 @@
+<Signature xmlns="http://www.w3.org/2000/09/xmldsig#" Id="DistributorSignature">
+<SignedInfo>
+<CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"></CanonicalizationMethod>
+<SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"></SignatureMethod>
+<Reference URI="author-signature.xml">
+<DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"></DigestMethod>
+<DigestValue>CSkGKnrxTdWY4XDJ9+X+NMDJWN2KoSrZ7q6oDRgIAk4=</DigestValue>
+</Reference>
+<Reference URI="bin%2Fsamsungctf">
+<DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"></DigestMethod>
+<DigestValue>AVoE3U9uEdfVYErXMCA0BKvaezSBXrGBDf7xbyDR5J8=</DigestValue>
+</Reference>
+<Reference URI="shared%2Fres%2Fq.png">
+<DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"></DigestMethod>
+<DigestValue>kflQSTsGWmyHMGGqiBfrptbfHi0JeDywu42nlkrKrQU=</DigestValue>
+</Reference>
+<Reference URI="tizen-manifest.xml">
+<DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"></DigestMethod>
+<DigestValue>ld9R+XTg+cb9zeCSITHwZYTSBjfpQ/XoLLokOu6NG7Q=</DigestValue>
+</Reference>
+<Reference URI="#prop">
+<Transforms>
+<Transform Algorithm="http://www.w3.org/2006/12/xml-c14n11"></Transform>
+</Transforms>
+<DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"></DigestMethod>
+<DigestValue>u/jU3U4Zm5ihTMSjKGlGYbWzDfRkGphPPHx3gJIYEJ4=</DigestValue>
+</Reference>
+</SignedInfo>
+<SignatureValue>
+b4NkgmEhkOa2bdmI33bjvdCGFcHZ5LIvdetbBB7eCfSOaq1VCzIRkJACQFPr/7sRTKigzITfNvrI
+NjKORPUeMWgKMrM867eE1ikpYeH2Lq5Rv9PXHM3NMtc++AOyUiomNGc4k38/gnT2rMoD6sC83yWh
+LjMVawo20TKNLqEBJaQ=
+</SignatureValue>
+<KeyInfo>
+<X509Data>
+<X509Certificate>
+MIICmzCCAgQCCQDXI7WLdVZwiTANBgkqhkiG9w0BAQUFADCBjzELMAkGA1UEBhMCS1IxDjAMBgNV
+BAgMBVN1d29uMQ4wDAYDVQQHDAVTdXdvbjEWMBQGA1UECgwNVGl6ZW4gVGVzdCBDQTEiMCAGA1UE
+CwwZVGl6ZW4gRGlzdHJpYnV0b3IgVGVzdCBDQTEkMCIGA1UEAwwbVGl6ZW4gUHVibGljIERpc3Ry
+aWJ1dG9yIENBMB4XDTEyMTAyOTEzMDMwNFoXDTIyMTAyNzEzMDMwNFowgZMxCzAJBgNVBAYTAktS
+MQ4wDAYDVQQIDAVTdXdvbjEOMAwGA1UEBwwFU3V3b24xFjAUBgNVBAoMDVRpemVuIFRlc3QgQ0Ex
+IjAgBgNVBAsMGVRpemVuIERpc3RyaWJ1dG9yIFRlc3QgQ0ExKDAmBgNVBAMMH1RpemVuIFB1Ymxp
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+hokKjzAzAgMBAAEwDQYJKoZIhvcNAQEFBQADgYEAvGp1gxxAIlFfhJH1efjb9BJK/rtRkbYn9+Ez
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+vKaYjeIsuEX6TVRUugHWudPzcEuQRLQf8ibZWjbQdBmpeQYBMg5x+xKLCJc=
+</X509Certificate>
+<X509Certificate>
+MIICtDCCAh2gAwIBAgIJAMDbehElPNKvMA0GCSqGSIb3DQEBBQUAMIGVMQswCQYDVQQGEwJLUjEO
+MAwGA1UECAwFU3V3b24xDjAMBgNVBAcMBVN1d29uMRYwFAYDVQQKDA1UaXplbiBUZXN0IENBMSMw
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+bE/UVLPh/tRNZPeGhzU4ejDDm7kzdr2f7Ia0U98K+OoY12ucwg7TYNItj9is7Cj4blGfuMDzd2ah
+2AgnCGlwNwV/pv+uVQIDAQABoxAwDjAMBgNVHRMEBTADAQH/MA0GCSqGSIb3DQEBBQUAA4GBACqJ
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+VhfnkHwPltmrpYVe
+</X509Certificate>
+</X509Data>
+</KeyInfo>
+<Object Id="prop"><SignatureProperties xmlns:dsp="http://www.w3.org/2009/xmldsig-properties"><SignatureProperty Id="profile" Target="#DistributorSignature"><dsp:Profile URI="http://www.w3.org/ns/widgets-digsig#profile"></dsp:Profile></SignatureProperty><SignatureProperty Id="role" Target="#DistributorSignature"><dsp:Role URI="http://www.w3.org/ns/widgets-digsig#role-distributor"></dsp:Role></SignatureProperty><SignatureProperty Id="identifier" Target="#DistributorSignature"><dsp:Identifier></dsp:Identifier></SignatureProperty></SignatureProperties></Object>
+</Signature>

SCTF/2018 Finals/baby_tpk/sctf/bin/samsungctf

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<manifest xmlns="http://tizen.org/ns/packages" api-version="2.3.1" package="samsungctf" version="1.0.0">
+    <profile name="mobile"/>
+    <ui-application appid="samsungctf" exec="samsungctf" multiple="false" nodisplay="false" taskmanage="true" type="capp">
+        <label>TPK</label>
+        <icon>q.png</icon>
+        <metadata key="iv" value="aXZpc2hlcmU="/>
+    </ui-application>
+</manifest>

SCTF/2018 Finals/baby_tpk/sctf/bin/samsungctf.i64

@@ -0,0 +1,16 @@
+from base64 import b64decode
+from binascii import unhexlify
+from Crypto.Cipher import CAST
+
+key = 'samsungctf_TPK'
+iv = b64decode('aXZpc2hlcmU=')
+
+data = '''
+5C E0 B9 F2 C4 1C 7D 73 68 F7 A5 F6 98 49 BF E1
+CF 5D 82 B2 59 D1 41 07 60 75 94 EC 3A D1 35 2B
+16 80 D0 C7 39 F8 B1 28 12 F9 6C 78 DE E4 9F BB
+'''.replace(' ', '').replace('\n', '')
+data = unhexlify(data)
+
+obj = CAST.new(key, CAST.MODE_OFB, iv)
+print obj.encrypt(data)

SCTF/2018 Finals/baby_tpk/sctf/shared/res/q.png

@@ -0,0 +1,52 @@
+import signal
+import random
+
+
+class LCG:
+    def __init__(self, s, k):
+        self.init_state = s
+
+        k1, k2, k3 = k
+        self.x = (k1 - 0xdeadbeef) % k3
+        self.y = (k1 * 0xdeadbeef) % k3
+        self.z = k2
+        self.m = k3
+
+    def __iter__(self):
+        self.index = 0
+        self.size = 32
+        self.s0, self.s1 = self.init_state
+        return self
+
+    def __next__(self):
+        if self.index >= self.size:
+            raise StopIteration
+
+        self.index += 1
+        s0, s1 = self.s0, self.s1
+        self.s0, self.s1 = s1, (self.x * s1 + self.y * s0 + self.z) % self.m
+        return self.s1
+
+
+if __name__ == '__main__':
+    signal.alarm(60)
+
+    s0, s1, k1, k2, k3 = [random.getrandbits(64) for i in range(5)]
+
+    s = (s0, s1)
+    k = (k1, k2, k3)
+
+    cnt = 16
+    for i, v in enumerate(LCG(s, k)):
+        guess = int(input())
+        if guess == v:
+            cnt += 1
+        else:
+            cnt -= 1
+
+        if i <= 16:
+            print(v)
+
+    if cnt >= 16:
+        with open('flag.txt', 'r') as f:
+            print(f.read())

SCTF/2018 Finals/baby_tpk/sctf/signature1.xml

@@ -0,0 +1,65 @@
+from pwn import *
+
+
+def egcd(a, b):
+    if a == 0:
+        return (b, 0, 1)
+    g, y, x = egcd(b % a, a)
+    return (g, x - (b//a) * y, y)
+
+
+def modinv(a, m):
+    g, x, y = egcd(a, m)
+    if g != 1:
+        raise Exception('No modular inverse')
+    return x % m
+
+
+def guess(num):
+    p.sendline(str(num))
+    return int(p.recvline())
+
+p = remote('lcg.eatpwnnosleep.com', 12345)
+
+d = 0xdeadbeef
+N = 16
+
+X = []
+for i in range(N):
+    X.append(guess(0))
+
+Y = []
+for i in range(1, N):
+    Y.append(X[i] + d * X[i-1])
+
+Z = []
+for i in range(1, N - 1):
+    Z.append(Y[i] - Y[i-1])
+
+m = None
+for i in range(2, N - 2):
+    m0, m1, m2 = Z[i-2], Z[i-1], Z[i]
+    m_next = m1*m1 - m0*m2
+    if m is None:
+        m = m_next
+    else:
+        m = egcd(m, m_next)[0]
+if m < 0:
+    m = -m
+log.success('M: 0x%x' % m)
+
+k = (Y[2] - Y[1]) * modinv(Y[1] - Y[0], m) % m
+log.success('K: 0x%x' % k)
+
+z = (Y[1] - k * Y[0]) % m
+log.success('Z: 0x%x' % z)
+
+s0 = X[N - 2]
+s1 = X[N - 1]
+for i in range(16):
+    num = ((k - d) * s1 + k * d * s0 + z) % m
+    p.sendline(str(num))
+    s0, s1 = s1, num
+
+p.recvline()
+print p.recvline()

SCTF/2018 Finals/baby_tpk/sctf/tizen-manifest.xml

@@ -0,0 +1,92 @@
+from random import randint
+from binascii import hexlify
+import sys
+
+
+def wline(msg=''):
+    sys.stdout.write(msg + '\n')
+    sys.stdout.flush()
+
+
+class MQpoly:
+    def __init__(self, terms, p, n):
+        self.terms = terms
+        self.p = p
+        self.n = n
+
+    def apply(self, vals):
+        if len(vals) != self.n:
+            raise ValueError('Values for n variables should be given')
+
+        quad, uni, c = self.terms
+
+        ret = 0
+        for i in range(self.n):
+            for j in range(i, self.n):
+                ret += quad[i][j] * vals[i] * vals[j]
+                ret %= self.p
+
+        for i in range(self.n):
+            ret += uni[i] * vals[i]
+            ret %= self.p
+
+        ret += c
+        ret %= self.p
+
+        return ret
+
+    def __str__(self):
+        quad, uni, c = self.terms
+
+        st_terms = []
+        for i in range(self.n):
+            for j in range(i, self.n):
+                v = quad[i][j]
+                if v != 0:
+                    st_terms.append('%dx%dx%d' % (v, i+1, j+1))
+
+        for i in range(self.n):
+            v = uni[i]
+            if v != 0:
+                st_terms.append('%dx%d' % (v, i+1))
+
+        if c != 0:
+            st_terms.append('%d' % (c,))
+
+        return ' + '.join(st_terms)
+
+    @classmethod
+    def random_element(cls, p, n):
+        quad = [[randint(0, p-1) if j <= i else None for j in range(n)]
+                for i in range(n)]
+
+        for i in range(n):
+            for j in range(i+1, n):
+                quad[i][j] = quad[j][i]
+
+        uni = [randint(0, p-1) for i in range(n)]
+        c = randint(0, p-1)
+
+        terms = (quad, uni, c)
+        return cls(terms, p, n)
+
+
+if __name__ == '__main__':
+    p = 131
+    n = 32
+
+    with open('flag.txt', 'rb') as f:
+        flg = f.read()
+
+    with open('/dev/urandom', 'rb') as f:
+        flg += f.read(n - len(flg))
+
+    mq = MQpoly.random_element(p, n)
+    wline(str(mq))
+    for i in range(n+1):
+        lst_1 = sys.stdin.buffer.read(n)
+        lst_2 = [(b1 + b2) % p for b1, b2 in zip(lst_1, flg)]
+        clue = [mq.apply(lst_1), mq.apply(lst_2)]
+
+        wline(hexlify(bytes(clue)).decode())
+