flashmob
This is not the security model, this is the consensus model. It's based on probabilistic finality, meaning that the probability that a transaction won't be reversed increases as more blocks are added on top. One major advantage of PoS is that it has "Absolute Finality" - after a certain amount of blocks, it's absolutely impossible to do a 51% attack. (See https://medium.com/mechanism-labs/finality-in-blockchain-con...)
Note that a higher hashrate does not mean more secure, it's a common falsehood. The security of bitcoin depends on the percentage of miners that are honest - this is mentioned the bitcoin whitepaper. Fortunately, the incentives align for the majority of miners to stay honest, and this is what the whitepaper predicted.
The service has been sending out emails since about 2013. It only lets out a limited number of emails, and there's an anti abuse policy in place. The IP address always has a good reputation with Google and Microsoft, I am well aware of all the feedback loops.
You're right, currently the server is sitting in "rescue mode" and under OVH's instructions, I'm not allowed to swap it back to the normal hard disk boot. That's ok, I can still mount the disks manually via SSH and move everything out. So at least that's some good news - the server hasn't been seized.
The hosting bill has been paid up until December, so I'll will be looking to get a partial refund hopefully.
Anyways, gotta roll with the punches I guess. Thanks for your comment.
But what can you do? You can't police the messages for every potential form of abuse. (I've only ran an automated spam filter to make sure that the service is never used for blatant spam. I've also blanket-blocked some domains whenever I noticed a pattern in any abuse reports, and finally recipients were able to easily do a permanent block themselves). In any case, running a messaging service even more difficult if you're a small guy and not Facebook or Google.
I've added more information about the details of the suspension in another post on here: https://news.ycombinator.com/item?id=24998922
I've been hosting the site on OVH since 2016. The site hasn't changed much during this time, and I've been quite happy with their services until now.
A little bit about Guerrilla Mail: It its' first and foremost, an anti-spam solution. Nowhere on the website it says that's an "anonymous email" provider. In fact, the email sending feature prominently warned the user that their IP address would be included in the headers of the email sent. (The sending feature was not for anonymous email, but for the rare chance that a user needed to send an email from there or reply. Guerrilla Mail is mostly used for receiving)
The timeline for the suspension went like this:
On October 12th, I received what seemed like a canned message from the OVHCloud Abuse team, saying that my server was (quote) "used for a fraudulent activity" and threatening termination within 48 hours.
There was no further details about the nature of the "fraudulent activity". I've replied to the message asking to give more details.
On October 16, I've received a reply, but still no details about the specific case. They mentioned that, their quote: "the problem here is clearly, that your service is too easy to use for fraudulent and illegal activities. ", further threatening to shut down the service within 7 days "if the situation does not improve". They also suggested a list of measures that the site should take.
I've replied informing that most of measures that they suggested were already taken, plus some other measures including an anti-abuse policy that has worked well over the years.
On October 19, I received a reply, this time hinting that I should pay them for an additional service, their quote "Maybe you see an option in using a service which lets you customize the Whois-Record, so your contact details can be mentioned for abuse instead of ours.".
I've started to deeply consider such a service, but before I would take it up, I wanted to get more info about the alleged law enforcement requests they receive, that are never forwarded, so I've asked them for more information about these once again.
On November 2nd, I received a reply, but still no details about the specific case, or the rate of such requests, questions that I've asked previously were ignored. Again, they were offering the additional service, their quote "change of infra to have your own abuse contact in registry info".
At this stage I was ready to buy whatever they were offering. I've replied to the email with only two sentences "Is there someone I can speak with directly on your team? Let's do a 30 minute call and reach an understanding."
On November 4th, I received a reply notifying that the server has been suspended.
Btw, if there's anyone at OVH that wants to look at the issue, it is WTLXFRCVSG.85a1
My solution:
Use a Go FastCGI client library to call PHP by talking directly to php-fpm. It saves on the HTTP request overhead and no need to run a web server. Actually, php-fpm is a decent application server itself.
Edit: Here's a link to example code: https://github.com/tomasen/fcgi_client
Interesting to note, Microsoft bought Hotmail for $400 million the following year.
1. https://blog.ctm-it.com/it-support/blogs/matt-cannon/2013/49...
Quote: "The water of the Snowy River and some of its tributaries, much of which formerly flowed southeast onto the river flats of East Gippsland, and into Bass Strait of the Tasman sea, is captured at high elevations and diverted inland ".
This is great! You have users who are using your product, how could you not be happy? Find out why they are not converting, perhaps your offer isn't that great for their demographic? Note that even if they didn't pay to your service, they may be your biggest fans who may recommend your product to other people. DEA users are usually tech-savvy types, they are also the kind of people who are the early adopters when it comes to tech (since they were able to figure out how a DEA works & how to use one), and are probably the ones who normal people go to get advice. Don't forget that even if not a paying customer, they are still a customer in the sense that they could review your service or refer others through word of mouth! If you're blocking DEA services, it may end up costing you more.
Of course, assuming that they are unaware of how their user / client / employer will actually use the software, they should be fine.
This brings us to an interesting thought. Cryptocurrency transaction values have been steady growing, starting from pizzas to alpaca socks and now it's even possible to settle multi million dollar transactions. In the the future we'll probably see larger, billion dollar plus aquisitions settled in cryptocurrency, why not? For that to happen though, their marketcaps will need to rise significantly from what they are now, at least to multi trillion dollar levels.
I guess that's the problem - there is no practical way to disable plaintext email from the start. You may always need to accept the connection, see if the client will STARTTLS, disconnect if they do not and hope they don't re-try and keep hammering your servers with the same message, the error message "hey, i'm not accepting plaintext" will most likely get ignored.
BTW, what ever happened to SMTP on a dedicated TLS port (465)? Why did it get deprecated?
Actually, like you, I've also hand-rolled most of it myself, replacing the previous guy's architecture. It's been a lot of fun. No frameworks, no bootstrap, just a few dependencies here and there. Started with PHP, but now prefer to use Go for anything new. Also hand-rolled the SMTP server which turned in to a project on its own, https://github.com/flashmob/go-guerrilla
"Developers, developers, developers!"
These double-spend attacks are only successful if the receiving party doesn't wait long enough.
Also, could't find any sources from exchanges if they were actually successful? The article didn't mention which exchanges.
Quote:
"Blockchain data indicates that the attacker successfully reversed transactions as far back as 22 blocks, leading developers to advise raising confirmation requirements to 50 blocks."
So as long as exchanges wait 50 blocks before crediting, they should be all right.
This is similar to the problem for pilots, who can be distracted by mundane tasks due the complexity of controls in modern aircraft. If these tasks are removed, the pilot can focus on what's more important.
According to NASA " For the most part, crews handle concurrent task demands efficiently, yet crew preoccupation with one task to the detriment of other tasks is one of the more common forms of error in the cockpit."
https://asrs.arc.nasa.gov/publications/directline/dl10_distr...
One of the golden rules in crypto is to never disclose your holdings to anyone on the internet, yet people are using these apps without a second thought!