Qloader Quest -

Here’s a write-up for "qloader quest" — a plausible CTF or reversing challenge (likely from a platform like HTB, CTFlearn, or a custom binary exploitation/loader puzzle).

Since no specific binary or source is provided, I’ll base this on common patterns for challenges named qloader quest.

Initial Analysis

Running file qloader:

qloader: ELF 64-bit LSB executable, x86-64, dynamically linked, stripped

No obvious strings with strings qloader | grep -i flag.

Checking with ltrace/strace shows it opens a file named quest.bin if present, else uses an embedded payload. qloader quest

Step 2 — Stage 2 Unpacking

Running stage1_dec.bin alone crashes — it expects a magic value in RDX set by the original qloader. Replicate by running qloader under gdb, break after mmap of stage 1, dump the mapped memory after stage 1’s decryption routine.

Alternatively, static analysis shows stage 1 does RC4 decryption of stage 2 using a key derived from argv[0]. Here’s a write-up for "qloader quest" — a

Key: "qloader" → RC4 key.

Extract stage 2 (embedded in stage 1 at offset 0x1200), decrypt RC4: Initial Analysis Running file qloader : qloader: ELF

from Crypto.Cipher import ARC4
key = b"qloader"
with open("stage2_enc.bin", "rb") as f:
    enc = f.read()
dec = ARC4.new(key).decrypt(enc)
open("stage2_dec.bin", "wb").write(dec)

Stage 2 is a position-independent shellcode blob.

1. The Quest

The Quest is the atomic unit of work within qloader. It is not merely a function call; it is an object containing metadata about the task.

• ID: A unique identifier for the resource.
• Action: The actual asynchronous function (e.g., fetch(), fs.readFile()).
• Payload: Data to be passed into the action.