Breaking The Links: Exploiting The Linker

The recent discussion relating to insecure library loading on the Microsoft Windows platform provoked a significant amount of debate as to whether GNU/Linux and UNIX variants could be vulnerable to similar attacks. Whilst the general consensus of the Slashdot herd appeared to be that this was just another example of Microsoft doing things wrong, the author felt this was unfair and responded with a blog post that sought to highlight an example of where POSIX style linkers get things wrong. Based on the feedback received to that post, the author decided to investigate the issue a little further. This paper is an amalgamation of what was learnt.