This article is currently an experimental machine translation and may contain errors. If anything is unclear, please refer to the original Chinese version. I am continuously working to improve the translation.
This article assumes you already have a basic understanding of what BT (BitTorrent) and PT (Private Tracker) are.
0x00 Preface (Nostalgia & Rambling)
Back in the day, over a decade ago, when I was still in early elementary school, my family didn’t have broadband—we relied on a 3G wireless USB dongle with speeds under 5 Mbps. Watching Youku online meant settling for low-resolution videos.
Back then, I used BT torrents and tools like “Shuoshuo FLV Downloader” to hoard videos (movies were still in RMVB/FLV formats back then). I’d leave my PC downloading overnight and enjoy smooth playback the next day.
A few years later, we finally got broadband (I still remember the awe of seeing download speeds hit 1 MB/s). With China’s nationwide “faster speeds, lower prices” campaign, home internet quickly reached a point where streaming any media was seamless. That killed my need to pre-download videos—and I eventually deleted all of them.
It wasn’t until university, through a classmate, that I rediscovered some campus PT sites—registering for BYRPT and Beiyang Garden. But since I had little interest in movies, anime, or certain Japanese adult content sites, I never found valuable resources.
It was during a casual chat with a friend that I suddenly realized: PT site mechanisms have glaring loopholes. After spending some time digging into the protocols, I came up with some lesser-known cheating techniques not commonly discussed online. Here’s the write-up.
0x01 BT Today and PT
As of 2024, few legitimate resources are distributed via the BitTorrent network. Most pirated media sites now rely on their own servers or cloud storage (Baidu Netdisk, Alibaba Cloud Drive, Google Drive). Many torrents are practically dead—no seeders, no downloads.
Ironically, PT sites thrive due to their invite-only system and strict upload/download ratio requirements. Users actively “grind” upload stats, investing in hardware and high-speed connections. This keeps torrents alive and downloads fast. It also forces downloaders to seed for a while instead of leeching and leaving immediately… right?
Well, not exactly.
In reality, PT (Private Tracker) doesn’t—and can’t—modify the BitTorrent protocol. PT users rely on standard BitTorrent clients. The BitTorrent protocol was never designed for PT use, so logical vulnerabilities are inevitable.
Moreover, since PT sites mostly distribute pirated media, few developers are willing to invest serious time and effort into improving them. Many PT sites still run on outdated, poorly maintained software like NexusPHP. Without a unified standard, developing a dedicated PT client is out of the question—so we’re stuck with flawed, general-purpose BT clients.
0x02 Traditional Cheating
If you’re unfamiliar with the BitTorrent protocol, I recommend these two resources:
To fully understand the rest of this article, you should be familiar with BEncode encoding, BT file format (info_hash), peerId, Tracker protocol, and Peer protocol.
Tracker Protocol
The Tracker protocol governs how BT clients communicate with PT sites—it’s the only way clients and PT sites exchange data.
Here’s a typical Tracker request and response from packet capture:
1 | GET /announce.php?passkey=xxxx&info_hash=%f5%ea%60Mn%3b%ce%fc%fd%93%96%f9%d5%b2f%c0%24*%a34&peer_id=-qB4630-u-OFvmi_~fo9&port=12866&uploaded=0&downloaded=0&left=123456&corrupt=0&key=2F750FC7&event=started&numwant=200&compact=1&no_peer_id=1&supportcrypto=1&redundant=0 |
As you can see, the Tracker request is a simple HTTP GET, and the response is Bencoded data.
Key parameters in the request include:
passkey (your identity on the PT site)
info_hash (the hash of the torrent you want to download)
peer_id (your unique ID, composed of client string + random string, different per task)
uploaded (upload volume for this torrent)
downloaded (download volume for this torrent)
left (remaining bytes to download for this torrent)
Other parameters are less important here—key is a 32-bit random string generated by the client for BT Tracker identification (ignored by PT), port is your listening port, etc.
The decoded response includes complete, downloaded, incomplete, interval, and peers (list of seeding peers with IP, port, and optional peerId).
Now, the sharp reader probably noticed the most glaring issue: upload volume is self-reported. So you can just report whatever number you want.
This is the classic PT cheating method—forge Tracker requests to report fake upload stats. For more details, see: PT Cheating and Anti-Cheating
But this kind of cheating is relatively easy to detect: if your reported upload doesn’t match others’ reported downloads, you can identify cheaters by analyzing seeds with abnormal upload-download gaps (above a threshold).
0x03 More Cheating Methods
While common PT cheating tools only modify reported upload/download values (via client spoofing or MITM), the vulnerabilities go much deeper.
Faking Seeds to Earn Bonus Points
Faking upload stats is somewhat traceable, but faking seed count is much harder to detect. You can simply write a script that periodically sends announce requests to the Tracker, pretending to seed a torrent—without actually holding the files or even listening on the port. Memory and storage usage are negligible—you can run this on any spare machine to grind bonus points.
For obscure torrents, it’s normal for no one to download or for connectivity issues to prevent downloads. PT sites can’t easily flag someone for “fake seeding” just because no upload occurred. You can even combine this with real seeding—seed a few torrents genuinely while faking others—to make your behavior look more legitimate.
For sites like TJUPT that reward based on seeding duration, Hit & Run becomes completely risk-free.
Free Downloading (Leeching)
So far we’ve focused on inflating upload stats or bonus points. But let’s face it: PT isn’t a PCDN—uploading more doesn’t pay you money. The real goal is to download more, not to do charity.
So what if we could download for free? Is that possible?
Let’s look at what most cheating methods ignore: the Peer protocol.
Peer Protocol
The Peer protocol runs over TCP. You initiate a TCP connection to peers provided by the Tracker (IP:port), and seeders may also connect to you. Once either side establishes a connection, a handshake begins.
The handshake packet consists of:
- 20-byte fixed header:
\x13BitTorrent protocol - 8-byte reserved field (usually
\x00) - 20-byte info_hash
- 20-byte your peer_id
The peer responds with the same 20+8+20 bytes plus their own 20-byte peer_id. Once this is complete, the peers can exchange messages and begin transferring data (i.e., you can start downloading).
In theory, a peer could compare your sent peer_id with the one from the Tracker and reject mismatches. But no mainstream client actually does this check (e.g., see libtorrent code). Possible reasons:
- It’s unnecessary in standard BT, and the protocol doesn’t require it.
- Tracker delays or outages would cause connection issues and reduce P2P efficiency.
- Some clients use
no_peer_id, meaning Tracker responses may not include peer_ids—implementation is inconsistent. - peer_ids are public and can be scraped from Trackers; spoofing is trivial, so verification is meaningless.
- qBittorrent’s anonymous mode uses different random peer_ids for Tracker and peer connections, breaking such checks entirely.
Thus, peers don’t verify peer_ids, meaning we can download any torrent as long as we have the peer’s IP:port and the info_hash.
An obvious idea: request the peer list from a real PT Tracker, then use it to download the file directly. We can even delay the actual download after fetching the peer list to reduce suspicion.
Traditional methods that fake download stats still keep contacting the Tracker. Instead, we can cache the peer list and feed it directly to the client.
Of course, repeatedly contacting the Tracker without generating real traffic still looks suspicious.
A better and safer method: download many popular free torrents normally, collecting all seeding peers (especially seedboxes). When you want a paid torrent, initiate downloads directly from all those peers (using magnet links + a custom cheating Tracker). This completely bypasses the PT Tracker. To the PT site, your behavior looks 100% legitimate—yet you’re downloading paid content for free.
The only feasible anti-cheat method would be seeding honeypots into peer lists, but that’s hard to implement and deploy. It’s practically unlikely. Even if such honeypots exist, there are ways to counter them—though space limits prevent further discussion.
Banning Others’ Accounts
Using Peer protocol quirks, we can maliciously spike someone else’s traffic. Say I don’t like user A—I go to their profile, get their list of seeding torrents, and use one or two to find A’s IP and port. Then I connect to A and initiate massive download requests. A will generate suspicious upload traffic (e.g., uploading 1000GB from a 2GB torrent), but the PT site sees no real downloaders. The site may conclude A is faking upload stats and ban their account.
Others
Due to the inherently insecure nature of the BitTorrent protocol, PT anti-cheat systems can only rely on statistical analysis. This leaves plenty of room for manipulation.
For example, I could first leech many popular/RSS torrents, then fake being one of the seeders by reporting false upload stats—effectively trading downloads for fake uploads.
Or, I could take a popular torrent’s Peer List and turn it into a public BT torrent (using a self-hosted Tracker that returns PT peers).
0x04 Code Implementation
The following code is proof-of-concept (PoC) only. Many details are incomplete, and it may be detected by PT sites, resulting in account bans. Your inviter may also be penalized. Use at your own risk.
I wrote a crude experimental implementation in Golang. It includes only two features: caching Peer Lists for free downloads and flooding a peer’s upload traffic.
You might try modifying it to act as a MITM to steal Peer Lists from free torrents—this could achieve near 100% stealth, though I was too lazy to implement it myself.
Tips to avoid detection:
- Use the same client version as in the code (qBit/4.6.3). Update the code if the client updates.
- Don’t just leech—also upload and download other torrents normally.
- Target torrents with many seeders for leeching, or wait a while after getting the Peer List before leeching to reduce suspicion.
Open source on GitHub: https://github.com/lyc8503/PTHackPoC
0x05 Summary & Personal Thoughts
It started as a random idea, but ended up way longer than expected—both in code and blog length. Though I’ve achieved a form of “PT freedom,” I still haven’t found anything worth downloading. Maybe I’ll test with a few files, but my account will probably just end up collecting dust.
As for BT and PT themselves, if you’ve read this far, you’ve likely noticed their deep roots in the wild-west era of the early internet: copyright infringement (or “sharing spirit,” if you prefer) and a crude, insecure protocol design. It’s impressive that some PT sites have survived this long with all this technical baggage. Many NAS enthusiasts are essentially using their real-name broadband to openly distribute illegal content.
Is cheating on PT sites unethical? Personally, while PT sites use various unreliable methods to appear to deter cheating—reducing cheater numbers—technically, they haven’t solved the leeching problem. The current model just lets a few cheaters leech more comfortably, while ignoring the core issues is, frankly, avoidance.
Moreover, even without cheating, PT’s closed ecosystem and ratio system push users to grind uploads (or pay the admin). Subscribing to endless RSS feeds of useless free torrents just to boost upload stats is a waste of public bandwidth and causes unnecessary network congestion. Or buying a Seedbox to boost stats and then leeching—doesn’t really help long-term seeding.
While PT sites may survive in niche corners for a while longer, they’ll eventually be phased out by history. Maybe it’s time to move to more modern P2P solutions (like Resilio Sync). Or perhaps, in the age of streaming and cloud storage, P2P file sharing has already fulfilled its historical mission? After all, instead of spending money on hard drives or Seedboxes, why not support creators and legal content directly?
This article is licensed under the CC BY-NC-SA 4.0 license.
Author: lyc8503, Article link: https://blog.lyc8503.net/en/post/pt-hack/
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