Claim
There are reports from various people, that YAcoin has built in wallet stealer.

What you can do
It's a common feature for malware to activate its main task on random date, and add a mark to the computer so it doesn't do the same thing twice (like uploading the stolen wallet.dat twice after your wallet is already uploaded, it's a waste of resource).
Since you can't be too safe, if you have run YAcoin's client or modified minerd.exe and don't encrypt your wallet, make sure you install Bitcoin in another clean computer and send your bitcoin there.
Make sure you password protected your wallet on that new computer.

Does YACoin really have malware module in it ?
Who knows, it's possible that it's a joke, someone wants to drop YAC's price on orderbook.
Or, it's the real deal. The attackers want people to believe that all of the various malware report that we receive now is a joke, and further report will be ignored once the real attack is really launched.
Hence, the investigation.

Investigation
I'll list what I found here :

List of YACoin related binary

yacoin-qt-2013-05-08.zip (yacoin's main client, uploaded during YACoin launch)
https://mega.co.nz/#!UowEmZYS!AAK7DVwYoTqy96oTRzUaLCS0UMsAfosJiRQmBn1jzcA
Detection ratio : 0 / 46 https://www.virustotal.com/en/file/7381b3ea8e872d860cf8279b98cb74a01cd21ecebaa1af7e537a040b6c5ad1e7/analysis/1368286925/

yacoin-qt-2013-05-09.zip (yacoin's main client, updated binary)
https://mega.co.nz/#!5wgDnKyZ!QLfWTXNRMRTwmb60rfpuFgzH48BCl4fpwb8paeAaqRs
Detection ratio : 0 / 46 https://www.virustotal.com/en/file/8c1b9dcc90e163a357b3861c10d8cec67c351a928e0b5e1e0dcf74d65d4a4b76/analysis/

cpuminer-scrypt-jane-win32.zip (modified minerd to mine yacoin on multiple computer)
hxxp://mega.co.nz/#!IJRziTBD!ZCAKGC7fqYkyXsEDi9GB1RYiqIUqj2S9bEm6UI2y1no
Detection ratio : 6 / 46 https://www.virustotal.com/en/file/2b7e630cfb2d173eb14e4dd88a7879527f5c52cbc77ace0c0742942aad46faec/analysis/1368286565/

"antivirus friendly" version of minerd (don't download this, very suspicious)
hxxp://mega.co.nz/#!shoxkb5b!DjiCAQBQ627TaW0oet1C7mvqM7Q2-2u-g4kDRHbniU4
From : https://bitcointalk.org/index.php?topic=201050.0
Detection ratio : 16 / 46 https://www.virustotal.com/en/file/0ffa2116bf1027019ad94e9bf8e2340be427d6efbc9563e185096cf8550b4c3a/analysis/1368287421/

minerd_scrypt_jane.ZIP (another modified minerd to mine yacoin on multiple computer)
https://mega.co.nz/#!pUMBkbbY!cMJYcFqPCMr1idZBr30VsFw0tLY7y63J0N4RVNYMUBc
Detection ratio : 0 / 46 https://www.virustotal.com/en/file/01a79a608d33d1db4eb9382db029e89e581f6e0017ddb566e7826b45370596fd/analysis/

All investigation should be done in clean Virtual Machine, otherwise, it's useless since it's possible that your computer is already marked and the malware won't run wallet stealing routine twice.

"Victim" List - Alternate cryptocurrency section

FreeTibet / Jr. Member / Posts: 11 / DO NOT DOWNLOAD YACOIN - SENDS WALLET.DAT TO http://bitcoin-ticker.netne.net/u.p

Lewies Man / Jr Member / Posts: 45 / 2.374 bitcoins stolen after downloading yacoin


Brewins / Jr. Member / Posts: 69 / Yacoin developer stole more than 256 BTC!

D35TR0Y3R / Full Member / Posts: 108 / WARNING: YACOIN HAS A VIRUS BITCOIN STEALER

nocompare / Jr. Member / Posts: 14 / yacoin developers are a bunch of crooks, steals 900 BTC

"Victim List" - Newbie section

moneytronics / Posts: 1 / YACOIN STEALS YOUR WALLET DO NOT USE

jebwizoscar /  Posts: 5 / yacoin trojan

danieljoseph /  Posts: 1 / yacoin stole my 14.25 btc

SquishySquish /  Posts: 6 / bitcoin sent from my wallet?

netne.net Whois


If you find this is helpful, any donation would be welcome :
YAcj1cSecVtCZkPpcPnb2raXdJfb3vzine