Bitcoin Forum

5/27/13 - Crazy Night

For those of you not in our irc or on btc-e trollbox, etc its been a crazy night for litecoin and several pools. Things got a little weird on the litecoin network, pools got together with litecoin devs to try and work it out. The pools and devs are working together to get to the bottom of things and we will pass it along to you guys as we find out. In the meantime the pools are working together to sure up the network and keep data between pools consistent and clean. It's been a pretty crazy few days with ups and downs but we have been working around the clock on this and will continue to do so. As soon as the issue came up on the network tonight we got on it right away, LTC is ok, no need to panic, LTC devs are taking things seriously and are working just as hard. Consider sending a donation to the ltc devs to help support their great work and new development: https://forum.litecoin.net/index.php?topic=3874.msg27452#msg27452 - With the linking of pools and changes we made we hope to block any more of these attacks.

Probably right, I'm not putting on my tinfoil hat just yet. :P

I also want to know. I haven't found this info anywhere else, and my payments have been low the past week or so.

I also want to know. I haven't found this info anywhere else, and my payments have been low the past week or so.

pretty sure the difficulty went up a couple times

Even at current diff I should have been making 3 ltc a day, but I was making roughly 2.

Were you mining at weminetlc.com ?

Hi. I am Warren Togami, the lead developer on Litecoin-0.8.x. I am better known as the Founder of the Fedora Project, and I have worked on other open source projects like Spamassassin, K12Linux and Cyanogenmod. I spent the last two years in grad school. I need to clarify some points here.

Payouts below expected difficulty are sometimes normal as pool luck can go up and down.  Know your payout system.

5/25/13 - Pool Luck
As many of you have noticed the pool luck has been very bad the past 2-3 days and payouts therefore have suffered. We went from finding normally 80-90 blocks a day to finding 56 one day and in the 60's another. As your payouts are 100% based on the number of blocks we find, you will have most likely noticed lower payouts than normal.
While bad luck is possible we started to suspect other issues and worked with one of the litecoin devs to try to get to the bottom of why we werent finding the correct amount of blocks and see if it was just bad luck or other issues. We looked at many possible vectors of attack and diagnosed our connection to the litecoin network, latency of getting work, etc. We have identified a few possible vectors of attack and a few possible network issues and took steps to make changes to block these and improve the latter. Since making those changes we found 10 blocks in about an hour and luck drastically improved.
We will not be describing the possible attack vectors for obvious reasons as they are not well known or common and we cant confirm any of these vectors even were being exploited. What we do know is that things seem to be resolved and now that we are fiding the correct amount of blocks we expect payouts to go back to normal. We encourage all users to track blocks found on the block chain, every block can be traced back to the pool or person who mined it, we will be changing the pool mining address every 2 weeks starting tomorrow (this changes nothing for you, just makes it easier to check pool blocks found on the block explorer) to aid users in this process. Thank you for all of our dedicated miners who have weathered this issue and realize the value in our pool. We have worked non stop on this for the past 30 hours to work this out and will continue to monitor it closely.

27/May/2013
You may have noticed extremely large blocks and round times over the past 24hours. This was due to multiple issues with finding blocks. This issue was affecting multiple pools for most of the day. We are still unsure of the cause but we have no reason to suspect it was due to issues on the litecoin network, will continue our investigations on this and give more information when we have it. So far things seem back to normal but we are keeping a firm eye on things.
If you are experiencing frequent disconnections contact us ASAP.

Give-Me-LTC:

wemineltc and givemeltc seem to be owned by the same person:

http://whois.domaintools.com/wemineltc.com
http://whois.domaintools.com/give-me-ltc.com

Well it's quite a coincidence that both pools are registered by the same registrar?

Things are getting back to normal on our pool.   The recent rumors of supposed problems on the Litecoin network we believe were actually multiple clever attacks on pool servers, there was no instability in the Litecoin network itself.  Thanks to help from the Litecoin core devs, especially pooler of litecoinpool.org, we have found and fixed a share verification vulnerability in the pool server stratum implementation.  

The affected code is found here:
 
Code: [Select]

def diff_to_target(self, difficulty):
       '''Converts difficulty to target'''
       diff1 = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff0000
       return diff1 / difficulty

https://github.com/viperaus/stratum-mining/blob/master/lib/template_registry.py#L145
We don’t use this specific build but we had similar code for this part of the template_registry code.

We found new users as of a few days ago that had been using this exploit to cheat the pool and to steal coins from the legitimate miners.  We have taken appropriate steps to stop this from happening again.  We are attempting to inform all Litecoin pools of the exploit as we believe many pools who work off the same base code may be affected.  Suspected fake miners were clocking at up to150MH/s for 3-4 days. We suspect more cheaters were involved over the past 3-4 days which could have been at least partially to blame for the pools bad luck.

During deployment of the fix, we logged changes in valid hash rates.  The biggest detected confirmed cheater was Cryptopower who went from 30MH/s to 1MH/s (someone who also tried to bash our pool in forums), the payout address for this account is LYVLrqSQyrDYN1QqQz2icbsF1rbihSAEmK - they stopped mining altogether about 3 hours after all their shares were being rejected.  There are other accounts who we suspect may have been cheating, but without knowing for 100% sure, it would be dangerous and unfair to publish their information in case they are actually innocent.  We are continuing to analyze the logs to identify accounts that may have been involved.

If we get more info we will post in the news asap.  You will notice things have gone back to normal after sorting this out.

The issue was with the stratum code, not Litecoin. Some flawed code allowed a modified miner to submit fake shares. Being the nice guys they are, the LTC Devs found the issue and help close it. All pools using stratum would be affected.

That's how I understood it.


~BCX~

The pools are still hitting abnormaly large blocks. Est time is 13-15 mins and it ends up being 30, 40, 50 minutes every other hour at least.

There was even a 10,000,000 share block on give-me-ltc.

Mining seems at least 10% less profitable due to the extended block times and no one seems to notice or care.

Does anyone know of the official confirmed patch besides the one offered by a user in the litecoin forum post about this?