domingo, 30 de agosto de 2020

C++ Std::Condition_Variable Null Pointer Derreference


This story is about a bug generated by g++ and clang compilers (at least)
The condition_variables is a feature on the standard library of c++ (libstdc++), when its compiled statically a weird asm code is generated.


Any example on the link below will crash if its compiled statically:
 https://en.cppreference.com/w/cpp/thread/condition_variable



In this case the condition_variable.wait() crashed, but this happens with other methods, a simple way to trigger it:




If this program is compiled dynamically the crash doesn't occur:

Looking the dissasembly there is a surprise created by the compiler:


Compilers:
    g++  9.2.1+20200130-2
    clang++ v9

Both compilers are generating the "call 0x00"

If we check this call in a dynamic compiled:




The implementation of condition_variable in github:
https://github.com/gcc-mirror/gcc/blob/b7c9bd36eaacac42631b882dc67a6f0db94de21c/libstdc%2B%2B-v3/include/std/condition_variable


The compilers can't copile well this code in static,  and same happens on  other condition_variable methods.
I would say the _lock is being assembled improperly in static, is not exacly a null pointer derreference but the effects are the same, executing code at address 0x00 which on linux is a crash on most of cases.

More info


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How To Hack Facebook By Social Engineering Attack

This video is specially for educational purpose only. I'm not responsible for your any illegal activity. Thanks!

 Social Engineering Attack

Phishing is the fraudulent attempt to obtain sensitive information such as usernames, passwords, and credit card details (and money), often for malicious reasons, by disguising as a trustworthy entity in an electronic communication. The purpose of this video tutorial is to show you How hackers hacked any thing by Social Engineering Attack.

Phishing is a cybercrime in which a target or targets are contacted by email, telephone or text message by someone posing as a legitimate institution to lure individuals into providing sensitive data such as personally identifiable information, banking and credit card details, and passwords. The information is then used to access important accounts and can result in identity theft and financial loss.

Kali Linux has many tools for doing social engineering attacks. Setoolkit is the most powerful tool in Kali Linux to do a social engineering attacks over the same and different networks. 

Social Engineering over the same network requires the local IP address of your system just like this one 192.168.1.2. Now how you can get your local IP address from your system. To find local IP address just open up your terminal in Linux distribution:

Type: ifconfig wlan0 (if you are using WiFi)
Type: ifconfig eth0 (if you are using eth0)
Type: ifconfig (It display all information about your network)

Now you've another thing to do is that you just have to clone a web page you wanna clone like Facebook, g-mail, twitter etc. Similarly, If you wanna clone a facebook page so for this you just have to type www.facebook.com over your system's terminal for cloning a login page for Social Engineering attack.Still If you don't know how to do that so don't be worry, I did all the process practically in the below just go down and watch it!