HighPublic exploit

Privilege Escalation via LD_PRELOAD in FreeBSD rtld

IdentifiersCVE-2009-4146CWE-427

A vulnerability in the _rtld function of the Run-Time Link-Editor (rtld) in FreeBSD 7.1, 7.2, and 8.0 fails to clear the LD_PRELOAD environment variable when executing setuid or setgid binaries. This allows a local attacker to specify a malicious shared library via LD_PRELOAD, which is then loaded with elevated privileges, leading to privilege escalation. The issue is due to improper sanitization of environment variables in the dynamic linker.

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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.

Local users can exploit this vulnerability to execute arbitrary code with the privileges of setuid or setgid binaries, potentially leading to full system compromise if exploited against root-owned setuid binaries.

Mitigation

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

As a temporary mitigation, restrict access to setuid/setgid binaries and monitor for suspicious use of LD_PRELOAD. Consider using file system permissions and mandatory access controls to limit the ability of unprivileged users to exploit this vector until a patch can be applied.

Remediation

Patch, then assume compromise.

Upgrade to a version of FreeBSD in which the rtld has been patched to properly clear the LD_PRELOAD environment variable when executing setuid or setgid binaries. Apply all relevant security updates provided by the FreeBSD project.

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

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

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

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Vendor-by-vendor mapping

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

Social activity