CVE-2017-1000409 in C Library
Summary
by MITRE
A buffer overflow in glibc 2.5 (released on September 29, 2006) and can be triggered through the LD_LIBRARY_PATH environment variable. Please note that many versions of glibc are not vulnerable to this issue if patched for CVE-2017-1000366.
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Analysis
by VulDB Data Team • 12/25/2024
This vulnerability represents a critical buffer overflow flaw in the GNU C Library (glibc) that has persisted since the release of version 2.5 in 2006. The vulnerability specifically manifests when the LD_LIBRARY_PATH environment variable is manipulated, creating a condition where an attacker can overflow a buffer in the dynamic linker's library loading mechanism. This issue falls under CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of how environment variable handling can create exploitable conditions in system libraries. The flaw is particularly concerning because glibc serves as the foundation for virtually all Linux applications, making this vulnerability a potential gateway for widespread system compromise.
The technical execution of this vulnerability occurs through the manipulation of the LD_LIBRARY_PATH environment variable, which the dynamic linker uses to determine where to search for shared libraries. When an attacker crafts a maliciously long LD_LIBRARY_PATH value, the buffer handling code in glibc fails to properly validate the input length, allowing the overflow to occur. This condition is classified under the ATT&CK technique T1059.001 for command and scripting interpreter and T1068 for exploit for privilege escalation, as successful exploitation can lead to arbitrary code execution with the privileges of the running process. The vulnerability is particularly dangerous because it operates at the system library level, meaning that any application using glibc could potentially be exploited through this mechanism.
The operational impact of CVE-2017-1000409 extends far beyond individual application compromise, as it affects the fundamental library that supports the entire Linux ecosystem. Systems running vulnerable versions of glibc are susceptible to privilege escalation attacks that can result in complete system compromise, especially when combined with other exploitation techniques. The vulnerability's persistence since 2006 means that many legacy systems remain exposed, particularly in enterprise environments where patching cycles are slow or where older software versions are maintained for compatibility reasons. Organizations with systems running glibc versions prior to the 2.25 release are particularly at risk, as the vulnerability was addressed through a combination of input validation improvements and buffer size restrictions.
Mitigation strategies for this vulnerability require immediate attention to patching glibc to versions that have been hardened against buffer overflow conditions. The recommended approach includes updating to glibc 2.25 or later, which incorporates the necessary fixes for this specific vulnerability. System administrators should also implement environment variable sanitization practices, particularly in applications that allow user input to influence LD_LIBRARY_PATH settings. Additional protective measures include implementing strict library loading policies, using secure coding practices that validate environment variable inputs, and monitoring for unusual LD_LIBRARY_PATH usage patterns. Organizations should also consider implementing runtime protections such as stack canaries, address space layout randomization, and other exploit mitigations that can prevent successful exploitation even if the underlying vulnerability remains unpatched. The vulnerability serves as a reminder of the critical importance of maintaining current system libraries and the potential consequences of legacy software maintenance.