8th
09,05
It is a good introductory book on recent trends of computer hacking, especially on Packing. Personally, the part on ptrace-related vulnerability – loopholes of design philosophy – is the most interesting. As you may know, Linux has 3 optional permissions : read/write/execute. What if superuser set files as executable but not readable? In this case, there is one way to dump the loaded file in a memory to the file on hard disk. Ptrace is the key, which is the interface to debug processes in Linux. When executing a root-privilege file by spawning child with ptrace option, we can trap the loaded time as a parent process (execl).
An excellent case is in the hacking game. In order to go into higher level, we have to input the password to the root file. In this case, we can lunch the file but cannot read/write the file. If you can read the executable file, we can analyze that file, simply typing strings for example. However, while executing that file, we can see the content with this ptrace technique!
