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-   -   Mysterious symlink (https://www.linuxquestions.org/questions/linux-security-4/mysterious-symlink-4175439183/)

usr345 11-28-2012 01:54 PM

Mysterious symlink
 
I had a chat with a guy on Stackoverflow:

http://stackoverflow.com/questions/1...cutable-binary

Where he claims, that the hackers, have uploaded a symlink to his hosting directory and were able to access his dir from some other account on the server.

This has completely puzzled me, cause I am sure, that it's impossible to access the dir using a symlink, if you don't have sufficient rights. Does anybody know, how this could happen?

smallpond 11-28-2012 02:52 PM

Symlinks do not give any additional permissions.

Sounds like the server permissions were wack. Any hosting company that allows other users to access my files should be out of business shortly. Most likely it was another customer who found out the permissions problem and exploited it. How would anybody else know to do that?

Not enough information to know what's going on for sure, but suppose the server administrators were unbelievably stupid and have a program that gets run as root in a user-writable directory. Then the hacker replaces that program with a symlink to an executable in the upload directory. Now they can upload whatever script they want and it has access to everything.


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