mtgsig1.2简单分析[狗头]
{"a1": "1.2", # 加密版本
"a2": new Date().valueOf() - serverTimeDiff, # 加密过程中用到的时间戳. 这次服主变坏了, 时间戳需要减去一个 serverTimeDiff(见a3) !
"a3": "这是把xxx信息加密后提交给服务器, 服主校验成功后返回的一个dfpId", # dfpId. 服务器返回的dfpId数据包里, 有一个serverTimestamp字段. serverTimeDiff = serverTimestamp - Date.now()
"a4": "一个长48位的加密结果", #a5, a2以及一小段jsvmp运行后, 输出a4
"a5": "一个长320位的加密结果", # a2, a6, 以及下面的Ln, 计算后输出a5
"a6": "w1.2xxxxx这一段长512xxxxxxx", # w1.2 + 客户端环境的加密结果
"a7": wx["getAccountInfoSync"]().miniProgram.appId, # 小程序id
"x0": 3, # 源代码写死
"d1": md5ToHex(j) #a1, a2, a3, a4, a7以及上面加密过程中出现的一些数组, 经过运算后, 输出d1
}
Ln = {
"b1": {appId: "小程序id",envVersion: "release", version: "微信版本号"},
"b2": "一个url",
"b6": "微信的openId", # 这个玩意儿可以考虑置空
"b7": Math.floor(Date.now() / 1e3),
"b8": "17" # 不重要, 1-20给个随机值就行
}
PS:基于某评微信小程序的guard.js文件, 且文件经过简单的ast脱混淆.
1. 收集的环境Ne = {
DFP: ["app", "dfpid", "filetime", "fpv", "localid", "system", "timestamp", "ext", "sessionId"],
system: ["accelerometer", "albumAuthorized", "BatteryInfo", "batteryLevel", "Beacons", "benchmarkLevel", "bluetoothEnabled", "brand", "brightness", "cameraAuthorized", "compass", "deviceOrientation", "devicePixelRatio", "enableDebug", "errMsg", "fontSizeSetting", "language", "LaunchOptionsSync", "locationAuthorized", "locationEnabled", "locationReducedAccuracy", "microphoneAuthorized", "model", "networkType", "notificationAlertAuthorized", "notificationAuthorized", "notificationBadgeAuthorized", "notificationSoundAuthorized", "pixelRatio", "platform", "safeArea", "screenHeight", "screenTop", "screenWidth", "SDKVersion", "statusBarHeight", "system", "version", "wifiEnabled", "WifiInfo", "windowHeight", "windowWidth"],
BatteryInfo: ["errMsg", "isCharging", "level"],
safeArea: ["left", "right", "top", "bottom", "width", "height"],
WifiInfo: ["SSID", "BSSID", "autoJoined", "signalStrength", "justJoined", "secure", "frequency"]
}
1.1 环境加密逻辑(a6). 主要是找到收集了哪些环境, 以及环境对应的值.
加密函数中只有常见的加密运算符, 没有检测环境的异常分支或其他坑. 所以逆向中遇到的加密函数直接 复制粘贴到自己的代码里就好. 譬如:
vn = {
gzipSync: R,
compressSync: R,
strToU8: function (e, n) {
var a = e.length;
if (!n && "undefined" != typeof TextEncoder) return new TextEncoder().encode(e);
for (var t = new Je(e.length + (e.length >>> 1)), c = 0, r = function (e) {
t = e;
}, f = 0; f < a; ++f) {
if (c + 5 > t.length) {
var o = new Je(c + 8 + (a - f << 1));
o.set(t), t = o;
}
128 > (o = e.charCodeAt(f)) || n ? r(o) : 2048 > o ? (r(192 | o >>> 6), r(128 | 63 & o)) : 55295 < o && 57344 > o ? (r(240 | (o = 65536 + (1047552 & o) | 1023 & e.charCodeAt(++f)) >>> 18), r(128 | o >>> 12 & 63), r(128 | o >>> 6 & 63), r(128 | 63 & o)) : (r(224 | o >>> 12), r(128 | o >>> 6 & 63), r(128 | 63 & o));
}
return nn(t, 0, c);
}
};
function R(e, n) {
void 0 === n && (n = {});
var a = pn(),
t = e.length;
a.p(e);
var c = (e = ln(e, n, 10 + (n.filename && n.filename.length + 1 || 0), 8)).length,
r = n;
if (n = r.filename, e = 31, e = 139, e = 8, e = 2 > r.level ? 4 : 9 == r.level ? 2 : 0, e = 3, 0 != r.mtime && gn(e, 4, Math.floor(new Date(r.mtime || Date.now()) / 1e3)), n) for (e = 8, r = 0; r <= n.length; ++r) e = n.charCodeAt(r);
return gn(e, c - 8, a.d()), gn(e, c - 4, t), e;
}
gn = function (e, n, a) {
for (; a; ++n) e = a, a >>>= 8;
},
function J(e) {
function n() {
for (var e, n = ["xxxxxxxxxxxxxxxxxxxxxxxxxx", "xxxxxxxxxxxxxxxxxxxxxxxxxx"], a = [], c = 0; c < n["length"]; c++) {
e = "";
for (var r = n, f = r["length"], o = parseInt("0x" + r["substr"](0, 2)), d = 2; d < f; d += 2) {
var i = parseInt("0x" + r["charAt"](d) + r["charAt"](d + 1));
e += String["fromCharCode"](i ^ o);
}
a["push"](e);
}
return a;
}
var a = ke["codec"]["utf8String"]["toBits"](n()),
c = ke["codec"]["utf8String"]["toBits"](n());
return a = new ke["cipher"]["aes"](a), e = ke["mode"]["cbc"]["encrypt"](a, e, c), ke["codec"]["base64"]["fromBits"](e);
}
2. a2-a8加密前的准备工作.
2.1 a5, a4的加密逻辑(包含两段简单的jsvmp代码, 相对于mtgsig1.1的jsvmp代码, 服主很可能还在练手).
代码中调用的函数也都是简单的运算操作. 例:
Qn = function () {
for (var n, a, c = 256, r = []; c--; r = n >>> 0) for (a = 8, n = c; a--;) n = 1 & n ? n >>> 1 ^ 3988292384 : n >>> 1;
return function (n) {
if ("string" == e(n)) {
for (var a = 0, c = -1; a < n["length"]; ++a) c = r(a)] ^ c >>> 8;
return 306674911 ^ c;
}
for (a = 0, c = -1; a < n["length"]; ++a) c = r] ^ c >>> 8;
return 306674911 ^ c;
};
}();
function Z(e) {
var n = [];
return n = e >>> 24 & 255, n = e >>> 16 & 255, n = e >>> 8 & 255, n = 255 & e, n;
}
function X(e) {
for (var n = [], a = 0; a < e["length"]; a += 2) {
var c = e["charAt"](a) + e["charAt"](a + 1);
c = parseInt(c, 16), n["push"](c);
}
return n;
}
function W(e) {
e = encodeURIComponent(e);
for (var n = [], a = 0; a < e["length"]; a++) {
var c = e["charAt"](a);
"%" === c ? (c = e["charAt"](a + 1) + e["charAt"](a + 2), c = parseInt(c, 16), n["push"](c), a += 2) : n["push"](c["charCodeAt"](0));
}
return n;
}
function ae(e, n) {
var a = e["length"];
n ^= a;
for (var c = 0; 4 <= a;) {
var r = 1540483477 * (65535 & (r = 255 & e | (255 & e[++c]) << 8 | (255 & e[++c]) << 16 | (255 & e[++c]) << 24)) + ((1540483477 * (r >>> 16) & 65535) << 16);
n = 1540483477 * (65535 & n) + ((1540483477 * (n >>> 16) & 65535) << 16) ^ (r = 1540483477 * (65535 & (r ^= r >>> 24)) + ((1540483477 * (r >>> 16) & 65535) << 16)), a -= 4, ++c;
}
switch (a) {
case 3:
n ^= (255 & e) << 16;
case 2:
n ^= (255 & e) << 8;
case 1:
n = 1540483477 * (65535 & (n ^= 255 & e)) + ((1540483477 * (n >>> 16) & 65535) << 16);
}
return ((n = 1540483477 * (65535 & (n ^= n >>> 13)) + ((1540483477 * (n >>> 16) & 65535) << 16)) ^ n >>> 15) >>> 0 ^ 1540483477;
}
2.2 d1, 以及最终mtgsig赋值
var p = K((r = 4294967295 & i)),
l = new Uint8Array(W(v)["concat"](p)),
g = se["md5"](l),
y = Y(g["substring"](0, 15));
(y = 255 & (n ^ Qa(p)))
请问下计算a5 的时候 这里 n 的值有影响吗？ 遇到个问题, 怎么传递url计算呢?
我弄的也是1.2的版本, 但是a6那是w1.3
我用小程序打开F12控制台的话小程序就返回403, 我计算的a4代码和小程序打开F12时的是一样的
我看了小程序里计算a4时传的参数, 我跟着小程序那样传递计算出来的结果是和小程序一样
但是用不了, 怀疑小程序打开F12控制台返回403就是检测到了调试环境然后计算a4这里出了什么问题
a4是通过传递的url计算出来一个w值, 还有a5, 然后用这个w值和a5取哈希值进行异或运算, 然后md5ToHex, 最后得到计算a4的3个参数
通过这3个参数计算出a4
所以a4需要 url, 需要a5, 还有a2
d = 4294967295 & a2
S = 取哈希(url计算的w值, a2)
A = 取哈希(a5, a2)
_ = md5ToHex( )
a4 = 计算a4(S, A, _)
以上就是a4计算的步骤
现在怎么计算w值呢, 弄了好久都没弄好, 有交流的吗
我现在就差怎么传递url计算a4的值了 https://pic.ziyuan.wang/2023/10/11/guest_04c486000adf0_IP117.183.226.149_UPTIME1697022669.png
福仔 发表于 2024-10-21 10:24
遇到个问题, 怎么传递url计算呢?
我弄的也是1.2的版本, 但是a6那是w1.3
不知道改动了什么, 或者我没注意到, 直接把url传递进去就可以计算出w值
抓包来的mtgsig解密后重新加密都能完全还原了, 但是还是403
估计还是有什么参数影响了 {:1_886:} 很不错哦 有点东西 感谢大佬的分享！ 看到了 a1就是 老M 发表于 2023-10-18 14:42
1.1不是随便撸么 一米七五 发表于 2023-10-27 15:07
1.1不是随便撸么
补下环境,改几个方法.. 一米七五 发表于 2023-10-27 15:07
1.1不是随便撸么
H5端现在都还是1.1吧 老M 发表于 2023-10-27 17:47
H5端现在都还是1.1吧
shide