Could someone DDoS Tor by abusing exitmap ?
> But if you ignore the warning and go ahead with the login, the attacker does three things: > 1. Steals your password
This shouldn't affect key-based authentication, though
Also, this from Marc-Etienne M.Léveillé email linked in your post:
> Another possibility is a compromised hosting provider. We identified a couple of them in the past where their management servers were compromised by Ebury and their customers' VPSes, containers, etc., ended up running Ebury as well.
Provider-side compromise of customer VPS instances has been a growing trend in recent years. I stopped hosting anything privacy-related on VPS in favor of dedicated hardware. Many people still don't understand how easy it is for a provider to silently dump and/or manipulate both RAM and disk space in real-time.
Depends what you mean by key and what you mean by affect. They can still MITM you if your using pubilc key authentication and you accept the servers host key without verifying it.
(Just don't turn on ForwardAgent)
That depends on the VPS technology stack being used. IIRC, at least Amazon uses hardware features like IOMMU that prevent any kind of access to the guest's memory from the host side.
It is probably an useful layer because some of the attacks are not feasible for a remote attacker who has compromised the host but require actual physical access. But the marketing spiel of protecting your data from Amazon itself is just lies, physical access is more powerful than root access, no exceptions.
I'd trust Amazon and Google more than most others when it comes to stuff like formally verifying hardware security solutions and also doing active research against threats posed by malicious internal staff.
It's not actually in their interest to look too closely. They know they are selling snake oil, and they do not care if it works. The only function of the technology, as far as they are concerned, is to be something they can market to customers who are scared at running on public cloud, and either they never intend to exploit it, in which case it doesn't matter if it doesn't work, or they do, in which case they don't want the vulnerabilities to be found and fixed. Either way, there is no upside to them for going spelunking.
I can tell you from direct experience on the inside at AWS that they care tremendously about virtualization security.
It's why they never let two tenants share a physical core simultaneously; they were prepared against side-channel attacks before Spectre and Meltdown were discovered.
It's why they never supported Intel SGX, preferring instead to sequester processors for confidential workloads (Nitro Enclaves), and why modern EC2 instances support memory encryption (Graviton + AMD SEV-SNP).
It's why, when you improperly remove a chassis from its cabinet, a mechanism destroys a key component containing the machine's attestation and encryption keys, rendering it useless.
It's why they delegated a large amount of security surface, including practically all I/O functions, to their off-CPU Nitro card.
Fact is if you put it in the cloud you lost control. Data, services and integrity is gone. Uploading your stuff to Pirate Bay may actually be more secure because downloading it is maybe illegal :-)
Such as what? Point to examples, please; don't just thread-crap hand-wavy statements like this.
Customers are free to--and are in fact encouraged to--use their own keys to encrypt their data both in transit and at rest.
> Fact is if you put it in the cloud you lost control. Data, services and integrity is gone.
The alternatives are arguably worse. You can't get anywhere near the durability of a cloud provider with any economically feasible alternative. Moreover, regardless of where you store data, law enforcement will be able to demand it be turned over with a valid warrant, and it's far easier for them to break down your door and collect it from your homelab servers (or just walk away with them under their arms) than to get into a Tier 1 cloud provider's data center and decrypt the encrypted data from it.
AMD SEV technically encrypts guest memory with key that is unavailable to hypervisor but there are still other ways to mess with VM inside, like via IO devices or the provided storage.
... which AWS provides via the dedicated Nitro card to the VMs directly.
Yes, as long as you trust AMD's implementation to not be broken, which to my knowledge hasn't happened yet.
The thing is, that only helps Tor users who are happy for their PC to contain evidence of what they were doing over Tor (such as a known hosts file listing).
If your security requirements are so high your PC contains no evidence whatsoever of what you were doing over Tor, you wouldn't get the banner.
There used to be that "key art" that was posted to make it more visibly distinct, but I think that feature got discontinued.
Host *
VisualHostKey yes
If anything, it's a miracle that there is 3000 of them. Although you can safely assume that a good portion of them (if not the majority) are operated by state intelligence services, cybersecurity companies and bad actor, who will log everything that pass through their node (and might be able to decrypt them one day).
DEF CON 22 - Adrian Crenshaw- Dropping Docs on Darknets: How People Got Caught
I liked the idea of it, especially since it was a time where ISPs were really cracking down on BitTorrents. But after seeing a few index sites inside the network, I quickly realized how much of that network was CSAM.
Deleted that and never looked back.
And relay operators (not exit nodes) don't face any issues. Don't let the unreasonable fear blind you.
A good dozen engineers in a team of 50 ran relays, one bold fool ran an exit node and was falsely fingered for CSAM type crimes during my tenure. The net effect was no one ran relays anymore. The poor exit operator remains an Irish to this day because he has dozens of headlines about his arrest and none about the dropped charges.
How come no one has done that for the dark web? That we know of at least? It would be incredibly annoying for cops to suddenly go knocking on 15 thousand doors of completely random people.
Also depending on country you might be accused by aiding them, and it would be upon you to explain the court you have no control who uses the exit node nor their ID
TLDR: on Oct 2, 333 exits (~10% of Tor exits) started redirecting port 22 to 12 interception servers running a paramiko-based MITM that stole passwords and tried to drop Ebury on the target.
[1] - https://ifconfig.me/
It's been discussed on the mailing list: https://lists.torproject.org/mailman3/hyperkitty/list/tor-re...
That doesnt prove FranTech itself was compromised, but its a strong cluster. AFAIK nobody has contacted them yet, if no one does, I plan to give them a heads up in the coming days.
It's a good policy to permit Tor exit nodes but it means their network will egress some of the most untoward behavior so that is expected and I would not default to assuming they are compromised, rather have some of the highest concentration of Tor exit nodes. There are pros and cons to such providers and you found one of them.
- Hide where you are in the world from your employer, who owns the server. (On vacation?)
- You're hacking the server.
When you're behind a restrictive firewall which blocks anything other than HTTP/HTTPS (like at an Internet café), or when there's some upstream routing issue making reaching the server directly impossible from your location (these can be a pain to diagnose).
Or perhaps it's simply your default: you proxy everything through Tor, and need a reason to not go through it.
(And then proxying via your home is much faster and safer. You can do websocket-based proxy, but even exposing ssh server on port 443 works in a lot of places!)
People ssh over Tor for the same reason they use Tor for any network activity: To make confidential 1) your identity to the remote host and 2) your activities to your network providers (including your ISP/workplace/etc.).
If you want only confidential content, ssh is sufficient and so is https for web browsing. If you want the other things, you must use Tor or maybe something similar.
If so, the benefits and costs of anonymity, including legal benefits, are well-known. Why start that discussion over?
1. It can't steal your password, since the private key never leaves your client;
2. It can observe each command you type, but it can't open a connection to the real server to know how it would respond to your commands;
3. It can't open any connection to the real server (it will fail authentication), so it can't do anything to the real server.
If you really like passwords, there are ways to configure sshd to require both a client key and a password, in that order.
The simplest way is to just launch the servers yourself, using a cloud provider. Tor is completely OK with exit node operators being anonymous, and with exit nodes running in cheap cloud data centres.
https://forum.torproject.org/t/tor-relays-shutting-down-my-4...
People say that even running a middle or guard node can get your IP blacklisted. I don't have personal experience of this because I don't use my home IP for regular use, just for selfhosting. All the other devices run on a network wide commercial VPN so if it did happen it wouldn't be an issue.
2>/dev/null && echo nopass || echo maybe) || echo none)"
A human would simply run the two commands in sequence and parse errors on the remote side - this would have gave more information about unexpected errors.
Whatever you try, whether Tor or VPNs or whatever - doesn't matter when the cops come knocking. VPNs are coming under legal attack now, and more and more sites refuse to work with them. You can say you're just running a relay, but if it came from your server they will put you in jail. Or consider the cyrpto anonymizer services - the folks running them might claim ignorance of where the crypto is coming from or going to - but they still go to jail.
If you want privacy, you have to get it at the ballot box.
can someone explain to me how SSH keys would have prevented this MITM? My understanding is that when the user gets the message from their SSH software that says "Warning! This SSH fingerprint has changed" and is prompted to re-login, that would happen whether it is by password or by key. So how would keys prevent this? One still has to re-link the SSH endpoints, and do it over a compromised connection in this case.
You have already sent the password to the mitm already.
Question: Where to get these hardware keys? Which are good options and why?
I switched over to using that in Terminus recently instead of having Terminus generate and manage the private ssh keys.
Likewise, many Mac and MacBook machines have Secure Enclave too that can store private keys in hardware and works with the ssh client that comes with macOS. But I have not personally started using that yet. Will soon though. You then use TouchID to approve each login operation that ssh is performing.
Yubikey is cool too. I’ve used it mainly for other things than ssh.
Whatever solution you go with, have a backup or another way to restore access when your hardware key eventually breaks and cannot be used.
For example, instead of buying one Yubikey buy three and give each of them access to the same places. Keep one on you, one at home, and one somewhere else. Rotate between using each of them every couple of weeks so you are sure they all still work and that all of them have the accesses to all the same places.
In the case of ssh, you probably either have physical access to the target machine or you have VNC management from the hosting provider, etc, that you can fall back to if you misplace or damage your hardware key. So if you only use the hardware key for ssh and you have other means like those to get back in then having just a single hardware key is mostly fine.
Reputable vendors of those hardware keys included Yubikey and Token2, among others. You are really just using them as FIDO2 tokens, so go for what's reputable there.
If you are just getting started, you can generate and use software-backed keys (using ssh-keygen) and copy the public keys to servers' authorized_keys file using ssh-copy-id (or manually adding it). You should probably start learning this way (with plenty of online guides, and fewer risks of an old server implementation not supporting FIDO2 credentials), and then move to hardware keys once you understand the mechanics of copying around public keys, etc. Your password manager might also support acting as an SSH agent for key based logins - I believe Bitwarden and some others now do this, for example.
Yubikey benefits is it stores the keys in the hardware if your laptop is compromised somehow or stolen they at least don't get all the ssh keys too
But you should also just listen to the big warning that says "IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"
Wrote up the cleanup: isolate the clanker, retire the leftovers, move admin logins to a hardware key with touch and PIN. https://gist.github.com/AUAggy/c1881c1efd85b6cc46d3564ac9012...
If you are on a compatible Apple MacBook you can also use Touch-ID https://news.ycombinator.com/item?id=50175882
Collection of unencrypted data points to other players as well that have been known to have great interest in Tor exit nodes etc., but they're careful and not usually this noisy, so probably newgen trolls.