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fix: use forwarded deviceIp for web-context MoonPay buy payment URLs #4205

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Merged
kajoseph merged 1 commit into from
Jul 24, 2026
+52 −7
Merged

fix: use forwarded deviceIp for web-context MoonPay buy payment URLs #4205

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29 changes: 22 additions & 7 deletions packages/bitcore-wallet-service/src/externalservices/moonpay.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -190,6 +190,8 @@ export class MoonpayService {
}

moonpayGetSignedPaymentUrl(req): { urlWithSignature: string } {
// moonpayGetKeys deletes env/context from the body, so read context first
const isWebContext = req.body.context === 'web';
const keys = this.moonpayGetKeys(req);
const SECRET_KEY = keys.SECRET_KEY;
const API_KEY = keys.API_KEY;
Expand Down Expand Up @@ -225,15 +227,28 @@ export class MoonpayService {
if (req.body.paymentMethod) qs.push('paymentMethod=' + encodeURIComponent(req.body.paymentMethod));
if (req.body.areFeesIncluded) qs.push('areFeesIncluded=' + encodeURIComponent(req.body.areFeesIncluded));

const deviceIp = Utils.getIpFromReq(req);
if (!deviceIp) {
// Web requests are proxied through the bitpay backend, so the IP on this
// request belongs to that server, not the customer. The proxy captures the
// customer's public IP and forwards it as deviceIp. Web credentials are only
// held by the proxy, so the forwarded value is trusted for that context only.
// If the proxy does not forward an IP, omit allowedIpAddress rather than
// signing an IP the customer will never match.
let deviceIp = isWebContext ? req.body.deviceIp : Utils.getIpFromReq(req);
if (!deviceIp && !isWebContext) {
throw new ClientError('Could not determine device IP address');
}
const allowedIpAddress: string = Bitcore.crypto.Hash.sha256hmac(
Buffer.from(deviceIp),
Buffer.from(SECRET_KEY)
).toString('base64');
qs.push('allowedIpAddress=' + encodeURIComponent(allowedIpAddress));
if (deviceIp) {
// Canonicalize before hashing: HMAC is byte-exact and MoonPay hashes the
// plain IPv4 it observes, while dual-stack sockets report IPv4 clients as
// IPv4-mapped IPv6 (::ffff:1.2.3.4) - strip the prefix so both sides
// hash the same string
deviceIp = String(deviceIp).trim().replace(/^::ffff:/i, '');
const allowedIpAddress: string = Bitcore.crypto.Hash.sha256hmac(
Buffer.from(deviceIp),
Buffer.from(SECRET_KEY)
).toString('base64');
qs.push('allowedIpAddress=' + encodeURIComponent(allowedIpAddress));
}

const URL_SEARCH: string = `?${qs.join('&')}`;

Expand Down
30 changes: 30 additions & 0 deletions packages/bitcore-wallet-service/test/integration/externalservices/moonpay.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -292,6 +292,36 @@ describe('Moonpay integration', () => {
}
});

it('should hash the forwarded deviceIp instead of the request IP for web context', () => {
req.body.context = 'web';
req.body.deviceIp = '203.0.113.42';
const data = server.externalServices.moonpay.moonpayGetSignedPaymentUrl(req);
should.exist(data.urlWithSignature);
data.urlWithSignature.should.equal('widgetApi4?apiKey=apiKey4&currencyCode=btc&walletAddress=bitcoin%3A123123&baseCurrencyCode=usd&baseCurrencyAmount=500&externalTransactionId=123123&redirectURL=bitpay%3A%2F%2Fmoonpay&allowedIpAddress=HkPyqsZMUzAgsEx27Tlz%2B5XfZHaH0fSfWV%2FMKR7JAPc%3D&signature=B%2Bw0TTQiy8%2Ffq6QeoeSf4dKpdPHZ%2F2EnBB1S4UotNGM%3D');
});

it('should canonicalize IPv4-mapped IPv6 deviceIp before hashing', () => {
req.body.context = 'web';
req.body.deviceIp = '::ffff:203.0.113.42';
const data = server.externalServices.moonpay.moonpayGetSignedPaymentUrl(req);
should.exist(data.urlWithSignature);
data.urlWithSignature.should.equal('widgetApi4?apiKey=apiKey4&currencyCode=btc&walletAddress=bitcoin%3A123123&baseCurrencyCode=usd&baseCurrencyAmount=500&externalTransactionId=123123&redirectURL=bitpay%3A%2F%2Fmoonpay&allowedIpAddress=HkPyqsZMUzAgsEx27Tlz%2B5XfZHaH0fSfWV%2FMKR7JAPc%3D&signature=B%2Bw0TTQiy8%2Ffq6QeoeSf4dKpdPHZ%2F2EnBB1S4UotNGM%3D');
});

it('should omit allowedIpAddress for web context when no deviceIp is forwarded', () => {
req.body.context = 'web';
const data = server.externalServices.moonpay.moonpayGetSignedPaymentUrl(req);
should.exist(data.urlWithSignature);
data.urlWithSignature.should.equal('widgetApi4?apiKey=apiKey4&currencyCode=btc&walletAddress=bitcoin%3A123123&baseCurrencyCode=usd&baseCurrencyAmount=500&externalTransactionId=123123&redirectURL=bitpay%3A%2F%2Fmoonpay&signature=13Q%2BET1UQLnCqCyg3stDAN4%2FTQ8QB009LcuAP1y6B%2FI%3D');
});

it('should ignore a body deviceIp for non-web context and use the request IP', () => {
req.body.deviceIp = '203.0.113.42';
const data = server.externalServices.moonpay.moonpayGetSignedPaymentUrl(req);
should.exist(data.urlWithSignature);
data.urlWithSignature.should.equal('widgetApi2?apiKey=apiKey2&currencyCode=btc&walletAddress=bitcoin%3A123123&baseCurrencyCode=usd&baseCurrencyAmount=500&externalTransactionId=123123&redirectURL=bitpay%3A%2F%2Fmoonpay&allowedIpAddress=CN35SFB5PKS4vkiZ4CglTxRgTAaUHBLGZcenAw6gHEY%3D&signature=3XxjRX3EMj2RNaoAwgOwFBOiVTXsgAS7C50uJf9SsvM%3D');
});

it('should return error if there is some missing arguments', () => {
delete req.body.currencyCode;
try {
Expand Down
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