CVE-2009-4147

This exploit leverages a vulnerability in FreeBSD's Run-Time Link-Editor (rtld) to bypass restrictions on environment variables like LD_PRELOAD for setugid binaries, achieving local privilege escalation to root. The exploit manipulates the environment to load a malicious shared library via LD_PRELOAD, which then executes a shell with elevated privileges.

This Metasploit module exploits a vulnerability in FreeBSD's run-time link-editor (rtld) where the `unsetenv()` function fails to remove `LD_*` environment variables, allowing arbitrary shared object loading via `LD_PRELOAD` for privilege escalation.