HighPublic exploit

Privilege Escalation via Untrusted Library Search Path in FreeBSD rtld

IdentifiersCVE-2009-4147CWE-427

CVE-2009-4147 is a vulnerability in the _rtld function of the Run-Time Link-Editor (rtld) in FreeBSD 7.1 and 8.0, specifically in libexec/rtld-elf/rtld.c. The vulnerability arises because the rtld does not clear certain environment variables (LD_LIBMAP, LD_LIBRARY_PATH, LD_LIBMAP_DISABLE, LD_DEBUG, LD_ELF_HINTS_PATH) when executing setuid or setgid binaries. This oversight allows local users to manipulate these variables to influence the dynamic linker’s library search path, potentially loading malicious libraries and gaining elevated privileges.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

A local attacker can exploit this vulnerability to execute arbitrary code with the privileges of a setuid or setgid binary. By setting one of the affected environment variables to reference a directory containing a malicious library, the attacker can cause the dynamic linker to load this library instead of the legitimate one, resulting in privilege escalation.

Mitigation

If you can’t patch tonight, do this now.

As a temporary mitigation, restrict access to setuid/setgid binaries to trusted users only, and monitor for suspicious use of the affected environment variables. Consider using file system permissions and mount options (such as noexec) to limit the ability to introduce malicious libraries in user-writable directories.

Remediation

Patch, then assume compromise.

Upgrade to a version of FreeBSD in which the rtld has been patched to clear the affected environment variables when executing setuid or setgid binaries. Ensure that all setuid/setgid binaries are rebuilt with the patched rtld.

PUBLIC EXPLOITS

Exploits

1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos (1 hidden).

VALID 1 / 2 TOTALView more in app

rtld_execl_priv_esc.rbMaturityWeaponizedFrameworkmetasploitVerified exploit

This repository contains a single Metasploit module (modules/exploits/freebsd/local/rtld_execl_priv_esc.rb) that exploits a local privilege escalation vulnerability in the FreeBSD run-time link-editor (rtld), specifically due to improper handling of LD_* environment variables in the unsetenv() function (CVE-2009-4146, CVE-2009-4147). The exploit targets FreeBSD 7.2-RELEASE and 8.0-RELEASE (amd64) and requires access to a writable directory (default: /tmp), a setuid executable (default: /sbin/ping), and the presence of the 'cc' compiler. The module compiles and drops several C files to disk, abuses LD_PRELOAD to load a malicious shared object, and ultimately executes a payload (default: reverse TCP shell) as root. The structure is typical for a Metasploit local exploit, with Ruby code orchestrating the attack and generating/compiling C payloads on the fly. The main fingerprintable endpoints are the default SUID binary (/sbin/ping) and the writable directory (/tmp).

Disclosed Nov 30, 2009rubyclocal

EXPOSURE SURFACE

Affected products & vendors

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VendorProductType

FreebsdFreebsdoperating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

1 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

1 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

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Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity