domingo, 7 de junio de 2020

OVER $60 MILLION WORTH OF BITCOINS HACKED FROM NICEHASH EXCHANGE

Over $60 Million Worth of Bitcoins Hacked from NiceHash Exchange. Bitcoin mining platform and exchange NiceHash has been hacked, leaving investors short of close to $68 million in BTC.
As the price of Bitcoin continues to rocket, surging past the $14,500 mark at the time of writing, cyberattackers have once again begun hunting for a fresh target to cash in on in this lucrative industry.
Banks and financial institutions have long cautioned that the volatility of Bitcoin and other cryptocurrency makes it a risky investment, but for successful attackers, the industry potentially provides a quick method to get rich — much to the frustration of investors.
Unfortunately, it seems that one such criminal has gone down this path, compromising NiceHash servers and clearing the company out.
In a press release posted on Reddit, on Wednesday, NiceHash said that all operations will stop for the next 24 hours after their "payment system was compromised and the contents of the NiceHash Bitcoin wallet have been stolen."
NiceHash said it was working to "verify" the precise amount of BTC stolen, but according to a wallet which allegedly belongs to the attacker — traceable through the blockchain — 4,736.42 BTC was stolen, which at current pricing equates to $67,867,781.
"Clearly, this is a matter of deep concern and we are working hard to rectify the matter in the coming days," NiceHash says. "In addition to undertaking our own investigation, the incident has been reported to the relevant authorities and law enforcement and we are co-operating with them as a matter of urgency."
"We are fully committed to restoring the NiceHash service with the highest security measures at the earliest opportunity," the trading platform added.
The company has also asked users to change their online passwords as a precaution. NiceHash says the "full scope" of the incident is unknown.
"We are truly sorry for any inconvenience that this may have caused and are committing every resource towards solving this issue as soon as possible," the company added.
Inconvenience is an understatement — especially as so much was left in a single wallet — but the moment those coins shift, we may know more about the fate of the stolen investor funds.
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Reversing Some C++ Io Operations

In general decompilers are not friendly with c++ let's analyse a simple program to get familiar with it.
Let's implement a simple code that loads a file into a vector and then save the vector with following functions:

  • err
  • load
  • save
  • main


Lets identify the typical way in C++ to print to stdout with the operator "<<"


The basic_ostream is initialized writing the word "error" to the cout, and then the operator<< again to add the endl.




The Main function simply calls  "vec = load(filename)"  but the compiler modified it and passed the vector pointer as a parámeter. Then it bulds and prints "loaded  " << size << " users".
And finally saves the vector to /tmp/pwd and print "saved".
Most of the mess is basically the operator "<<" to concat and print values.
Also note that the vectors and strings are automatically deallocated when exit the function.


And here is the code:


Let's take a look to the load function, which iterates the ifs.getline() and push to the vector.
First of all there is a mess on the function definition, __return_storage_ptr is the vector.
the ifstream object ifs is initialized as a basic_ifstream and then operator! checks if it wasn't possible to open the file and in that case calls err()
We see the memset and a loop, getline read a cstr like line from the file, and then is converted to a string before pushing it to the vector. lVar1 is the stack canary value.

In this situations dont obfuscate with the vector pointer vec initialization at the begining, in this case the logic is quite clear.



The function save is a bit more tricky, but it's no more than a vector iteration and ofs writing.
Looping a simple "for (auto s : *vec)" in the decompiler is quite dense, but we can see clearly two write, the second write DAT_0010400b is a "\n"



As we see, save implememtation is quite straightforward.




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