Hack Security Pro.pdf - Index of

Security
The only solution here is to never trust data controlled by a user. printf type functions must also
be used carefully. When a function takes as an argument a format chain, the latter must only be
formatted by the program itself and not the user.
Example :
One never writes:
sprintf(buf, argv[1]);
but one writes:
sprintf(buf, "%s", argv[1]);
4. Race Condition
A) Presentation
Even if they are among the least-known, “race conditions” are some of the most common bugs found
on software.
These vulnerabilities are extremely hard to identify and therefore to correct. Indeed, a program
functioning very well can host several of these bugs in a “silent” manner, in the sense that there is no
malfunctioning of the program, or at least not in a systematic way, but this can still be exploited in a
malicious way.
Most of the time, “race conditions” decide how robust the software is. The competing access to data
can cause application instability without any other consequences. However, there are many times (by
this I mean a very short lapse of time) when “race conditions” have security implications. In fact, file
system accesses are subject to course connect security states much more often than most people
believe.
In a constantly changing IT environment, where the multi-threading, multi-treating and distributed
computing are all the rage, this type of problem can only become more frequent in the future.
Definition
A “race condition” happens when several processes have access to and manipulate the same
information or data at the same time. To “keep it simple”, a “race condition” is encountered when an A
application will use information that is going to be modified in a more or less synchronous way by a B
application. We then have an abnormal functioning of applications due to the bad relative
synchronization of events.
“Race conditions” are often encountered on numerous applications: these are possible only in
environments where multi-threads are found, that is where executed processes allow a certain
interactivity or at least an asynchronous treatment of information, as can happen with Unix signals, for
example.
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