pich4ya

# author Pichaya Morimoto (p.morimoto@sth.sh)

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Vulns:
- Tar Unzip Path Traversal
- Tar content => Overwrite flask_session's file type

loknop

Solving "includer's revenge" from hxp ctf 2021 without controlling any files

The challenge

The challenge was to achieve RCE with this file:

<?php ($_GET['action'] ?? 'read' ) === 'read' ? readfile($_GET['file'] ?? 'index.php') : include_once($_GET['file'] ?? 'index.php');

Some additional hardening was applied to the php installation to make sure that previously known solutions wouldn't work (for further information read this writeup from the challenge author).

I didn't solve the challenge during the competition - here is a writeup from someone who did - but since the idea I had differed from the techniques used in the published writeups I read (and I thought it was cool :D), here is my approach.

testanull

package ysoserial.payloads;

import com.mchange.lang.ByteUtils;
import org.apache.commons.collections.Transformer;
import org.apache.commons.collections.functors.ChainedTransformer;
import org.apache.commons.collections.functors.ConstantTransformer;
import org.apache.commons.collections.functors.InvokerTransformer;
import org.apache.commons.collections.keyvalue.TiedMapEntry;
import org.apache.commons.collections.map.LazyMap;
import ysoserial.payloads.annotation.Authors;

phith0n

import socket
import random
import argparse
import sys
from io import BytesIO

# Referrer: https://github.com/wuyunfeng/Python-FastCGI-Client

PY2 = True if sys.version_info.major == 2 else False