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  • 2 votes cast
Dec
4
awarded  Commentator
Dec
4
comment Does every hash value have an inverse value?
Well as others pointed out we suspect hashes are surjective, but we really don't know. My mention of compression was to propose a straw man argument for why you can't easily reverse a hash because if you could you'd also have an amazing compression algorithm that defies logic that it could exist...and destabilize modern cryptography. I knew you weren't trying to compress anything.
Dec
2
comment Is protecting a parent folder secure enough to protect files within that folder?
Well we were talking about if I deny you the ability to a higher level folder then the looser permissions below that folder won't allow someone to access that file because the parent folder prevents them. So if an admin or a program doesn't get the permissions just right it won't compromise security so long as that parent folder denies people. That is somewhat comforting.
Dec
2
comment What is the real function and use of a DMZ on a network?
Absolutely makes sense, and extremely common. For example a Database would exist in the DMZ for your web server in the DMZ that is publicly accessible. But that database would be shielded from remote public connections, and only people on the trusted private network could reach the database.
Dec
2
comment Is protecting a parent folder secure enough to protect files within that folder?
I guess that means I can rest more easily should something or someone screw up the permission with the folder I'm not going to be compromised because of it.
Dec
2
awarded  Scholar
Dec
2
accepted Is protecting a parent folder secure enough to protect files within that folder?
Dec
2
awarded  Student
Dec
2
revised Does every hash value have an inverse value?
math error
Dec
2
asked Is protecting a parent folder secure enough to protect files within that folder?
Dec
2
awarded  Editor
Dec
2
revised Does every hash value have an inverse value?
added 683 characters in body
Dec
2
answered Does every hash value have an inverse value?
Jun
14
awarded  Supporter
Jan
2
comment Can SQL injection lead to remote code execution?
Actually @wireghoul's example exploit is exactly what the op was looking for. Better answer than the accepted answer.
Jan
2
comment Can SQL injection lead to remote code execution?
Interesting exploit thanks for sharing, but it's not the same exploit discussed above. Nothing is using the database to write a file to the database server. In your case it's pulling the php from the log file on the web server. Clever indeed. Just to restate what I said WASN'T implying that separating the database from web server keeps you safe as a general rule just that this exploit discussed in the answer wouldn't work if you did that alone.
Dec
31
comment Can SQL injection lead to remote code execution?
The first part of your comment was exactly what I said. I could change DateTime to MySpecialAttack, but I have to get MySpecialAttack code into a place where the app would load it (ie classpath), but if I could inject something on the class path why would I bother to modify the serialized object? If a serialized class was eval'ing a member I could see why modifying a serialized class might be helpful. But the real weakness is not serialized objects it's the ability for the attacker to add something to your extensions you load. Cut that off and the attacker can't do anything.
Dec
31
comment Can SQL injection lead to remote code execution?
In the serialization case you'd have to modify a pointer to the code, say a class name in the case of Java, to allow for arbitrary code execution. But then you'd have to get your class onto the classpath, and if you could do that then why bother with modifying a serialized object? If you can get something on the classpath you can just execute that code at load time.
Dec
31
comment Can SQL injection lead to remote code execution?
If your database was on another machine separate from your web server then this attack wouldn't be possible. You could create the PHP script but without an accessible PHP container to execute it you couldn't get execute it.
May
20
awarded  Teacher