CVE-2009-4029 in Automake
Summary
by MITRE
The (1) dist or (2) distcheck rules in GNU Automake 1.11.1, 1.10.3, and release branches branch-1-4 through branch-1-9, when producing a distribution tarball for a package that uses Automake, assign insecure permissions (777) to directories in the build tree, which introduces a race condition that allows local users to modify the contents of package files, introduce Trojan horse programs, or conduct other attacks before the build is complete.
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Analysis
by VulDB Data Team • 08/30/2021
The vulnerability described in CVE-2009-4029 represents a critical security flaw in GNU Automake versions 1.11.1, 1.10.3, and various branch releases from 1-4 through 1-9. This issue manifests in the dist and distcheck rules that are fundamental components of the automake build system used extensively across Unix-like operating systems. The flaw occurs during the creation of distribution tarballs for software packages that utilize Automake, creating a significant window of opportunity for malicious activity within the build environment.
The technical root cause of this vulnerability lies in the improper permission assignment mechanism within Automake's distribution creation process. When the dist or distcheck rules execute, they assign insecure permissions of 777 to directories within the build tree structure. This chmod 777 operation grants full read, write, and execute permissions to all users on these temporary directories. The assignment of such permissive permissions creates a race condition scenario where local users can exploit the time gap between directory creation and the final build completion process. This race condition fundamentally violates the principle of least privilege and creates an attack surface that adversaries can leverage to compromise the build integrity.
The operational impact of this vulnerability is substantial and multifaceted. Local users with access to the build environment can exploit this race condition to modify package files before the build process concludes, potentially introducing malicious code or Trojan horses into the distribution. The vulnerability enables attackers to manipulate the contents of the package files during the build process, which could result in the delivery of compromised software to end users. This represents a serious supply chain security concern where the integrity of software distributions can be compromised at the build stage. The vulnerability is particularly dangerous because it operates silently within the normal build workflow, making detection difficult and potentially allowing persistent compromise of software packages.
This vulnerability aligns with CWE-276, which addresses improper file permissions, and demonstrates characteristics consistent with ATT&CK technique T1505.003 related to "Malicious File Execution" through build system manipulation. The race condition aspect of this vulnerability also relates to CWE-362, which covers concurrent execution issues, and represents a classic example of how improper access control can enable privilege escalation through build process manipulation. Organizations relying on GNU Automake for software compilation are particularly at risk, as this vulnerability affects the foundational build infrastructure that many software projects depend upon.
The recommended mitigations for this vulnerability include immediate upgrade to GNU Automake versions that have patched this issue, typically versions 1.11.2 and later. System administrators should also implement proper access controls and monitoring of build environments to detect unauthorized modifications. Additionally, organizations should consider implementing automated build integrity verification processes and regularly audit their build systems for similar permission-related vulnerabilities. The patch for this vulnerability specifically addresses the directory permission assignment issue by ensuring that directories are created with appropriate, restrictive permissions rather than the insecure 777 setting that enabled the race condition.