CVE-2014-9761 in C Library
Summary
by MITRE
Multiple stack-based buffer overflows in the GNU C Library (aka glibc or libc6) before 2.23 allow context-dependent attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a long argument to the (1) nan, (2) nanf, or (3) nanl function.
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Analysis
by VulDB Data Team • 07/25/2022
The vulnerability identified as CVE-2014-9761 represents a critical stack-based buffer overflow flaw within the GNU C Library implementation that affected versions prior to 2.23. This issue manifests in the nan, nanf, and nanl functions which are part of the standard mathematical library used by numerous applications and system components. The flaw stems from inadequate input validation when processing long argument strings passed to these functions, creating a condition where maliciously crafted inputs can exceed the allocated stack buffer space. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which occurs when data written to a buffer exceeds its allocated bounds and overwrites adjacent memory locations on the stack.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable arbitrary code execution in certain contexts. Attackers capable of controlling the argument passed to these functions can manipulate the stack layout and potentially overwrite return addresses, function pointers, or other critical memory structures. This makes the vulnerability particularly dangerous in environments where applications process untrusted input through these mathematical functions. The attack vector requires context-dependent conditions, meaning an attacker must have the ability to influence the argument values passed to these functions, typically through input processing or argument manipulation within the application's execution flow.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1203 for Exploitation for Client Execution, as it provides a pathway for privilege escalation and code injection attacks. The affected functions are commonly used in mathematical computations, scientific applications, and system utilities, making the attack surface quite broad across different software domains. The vulnerability demonstrates the critical importance of proper input validation in standard library functions, as these components form the foundation upon which countless applications depend. Applications using glibc versions before 2.23 that process user-provided arguments through these functions are at risk of exploitation, particularly when running with elevated privileges or in environments where input sanitization is insufficient.
The recommended mitigation strategy involves immediate upgrading of glibc to version 2.23 or later, which contains the necessary patches to address the buffer overflow conditions. System administrators should also implement input validation measures to prevent overly long arguments from reaching these functions, though this approach provides only partial protection as the underlying library vulnerability remains. Additionally, deploying runtime protections such as stack canaries, address space layout randomization, and non-executable stack segments can help reduce the exploitation success rate even if the primary vulnerability is not patched. Organizations should conduct comprehensive vulnerability assessments to identify applications that may be indirectly affected through their use of vulnerable glibc functions, particularly in legacy systems or embedded environments where upgrading may be challenging. The vulnerability serves as a reminder of the critical security implications of standard library components and the necessity for continuous security monitoring and patch management across all system components.