CVE-2024-42381 is a vulnerability identified in the Homebrew package manager's brew tool for Linux systems, specifically in versions before 4.2.20. The flaw stems from the use of the ldd utility to load ELF (Executable and Linkable Format) files obtained from untrusted sources. The vulnerability exploits the handling of the .interp section within ELF binaries. The .interp section specifies the program interpreter for the binary, and by crafting a malicious ELF file with a custom .interp section, an attacker can cause arbitrary code execution during the binary relocation phase. This phase occurs before the user expects any downloaded package content to execute and is unsandboxed, meaning the code runs with the privileges of the user invoking brew without containment. The vulnerability is categorized under CWE-830, which involves improper validation of a binary's relocation information, leading to unexpected code execution. The CVSS v3.1 base score is 8.3, indicating high severity, with attack vector as network (AV:N), attack complexity high (AC:H), no privileges required (PR:N), user interaction required (UI:R), and impacts on confidentiality, integrity, and availability all rated high (C:H/I:H/A:H). Although no known exploits are reported in the wild, the nature of the vulnerability allows an attacker to execute arbitrary code by convincing a user to install or load a malicious ELF binary via Homebrew. This can lead to full system compromise, data theft, or denial of service. The vulnerability affects Linux users of Homebrew, particularly those who install packages from untrusted or third-party sources. The lack of sandboxing during the relocation phase exacerbates the risk. The vulnerability was reserved and published on July 31, 2024, and no official patches or mitigations beyond upgrading to brew 4.2.20 have been documented yet.

The impact of CVE-2024-42381 is significant for organizations using Homebrew on Linux systems. Successful exploitation allows attackers to execute arbitrary code with the privileges of the user running brew, potentially leading to full system compromise. This threatens confidentiality by exposing sensitive data, integrity by allowing unauthorized modifications, and availability by enabling denial-of-service conditions. Since the code execution occurs before the user expects any downloaded package content to run, it increases the likelihood of stealthy attacks and reduces the chance of detection. The vulnerability requires user interaction but no prior privileges, broadening the attack surface to any user installing or updating packages via Homebrew. Organizations relying on automated or semi-automated package management workflows that incorporate untrusted ELF binaries are particularly vulnerable. The absence of sandboxing during the relocation phase means that traditional containment strategies may be ineffective. This vulnerability could be leveraged in targeted attacks against developers, DevOps environments, or Linux-based infrastructure, potentially leading to lateral movement and further compromise within networks.

To mitigate CVE-2024-42381, organizations should immediately upgrade Homebrew to version 4.2.20 or later, where the vulnerability has been addressed. Avoid installing or loading ELF binaries from untrusted or unverified sources, especially those that could contain malicious .interp sections. Implement strict package source validation and use cryptographic signatures to verify package integrity before installation. Employ runtime monitoring tools to detect unusual process behaviors during package installation and binary relocation phases. Consider sandboxing or containerizing package management operations to limit the impact of potential code execution. Educate users and administrators about the risks of installing untrusted packages and the importance of applying security updates promptly. For environments with high security requirements, restrict the use of Homebrew or similar package managers to trusted internal repositories only. Regularly audit and monitor systems for signs of compromise related to package management activities. Finally, maintain up-to-date backups to enable recovery in case of exploitation.