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Data loss prevention

Protect sensitive data to prevent data loss, and send alerts to a webhooks server in the event of a data breach.

const DEBUG = true;
// TODO(signalnerve): Update this to a real URL!
const SOME_HOOK_SERVER = "https://api.pagerduty.com/hook";
/**
* Alert a data breach by posting to a webhook server
*/
function postDataBreach(request) {
return fetch(SOME_HOOK_SERVER, {
method: "POST",
headers: {
"content-type": "application/json;charset=UTF-8",
},
body: JSON.stringify({
ip: request.headers.get("cf-connecting-ip"),
time: Date.now(),
request: request,
}),
});
}
/**
* Define personal data with regular expressions.
* Respond with block if credit card data, and strip
* emails and phone numbers from the response.
* Execution will be limited to MIME type "text/*".
*/
async function handleRequest(request) {
const response = await fetch(request);
// Return origin response, if response wasn’t text
const contentType = response.headers.get("content-type") || "";
if (contentType.toLowerCase().includes("text/")) return response;
let text = await response.text();
// When debugging replace the response
// from the origin with an email
text = DEBUG
? text.replace("You may use this", "me@example.com may use this")
: text;
const sensitiveRegexsMap = {
creditCard: String.raw`\b(?:4[0-9]{12}(?:[0-9]{3})?|(?:5[1-5][0-9]{2}|222[1-9]|22[3-9][0-9]|2[3-6][0-9]{2}|27[01][0-9]|2720)[0-9]{12}|3[47][0-9]{13}|3(?:0[0-5]|[68][0-9])[0-9]{11}|6(?:011|5[0-9]{2})[0-9]{12}|(?:2131|1800|35\d{3})\d{11})\b`,
email: String.raw`\b[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}\b`,
phone: String.raw`\b07\d{9}\b`,
};
for (const kind in sensitiveRegexsMap) {
const sensitiveRegex = new RegExp(sensitiveRegexsMap[kind], "ig");
const match = await sensitiveRegex.test(text);
if (match) {
// Alert a data breach
await postDataBreach(request);
// Respond with a block if credit card,
// otherwise replace sensitive text with `*`s
return kind === "creditCard"
? new Response(kind + " found\nForbidden\n", {
status: 403,
statusText: "Forbidden",
})
: new Response(text.replace(sensitiveRegex, "**********"), response);
}
}
return new Response(text, response);
}
export default {
fetch(request) {
return handleRequest(request);
},
};