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FreeBSD Privilege Escalation: LD_PRELOAD Exploit Advisory Overview

Calendar Dec 01, 2009 • User Avatar Anthony Pell
1 min read
General Esm H446
Topics%20covered

Topics Covered

security advisory privilege escalation exploit root access environment variable FreeBSD runtime linking
An exploit for FreeBSD is in circulation that allows users with restricted access to escalate their privileges to root level. The problem is caused by a flaw in the run-time link editor (rtld) which, in certain circumstances, accepts specially crafted environment variables. According to Kingcope, the developer of the exploit, the flaw is "incredibly easy" to exploit by, for example, setting a path to a specially crafted library for the LD_PRELOAD environment variable and then starting an SUID program like Ping. LD_PRELOAD instructs the loader to load additional libraries when starting a program

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