CVE-2010-3353 in Cowbell
Summary
by MITRE
Cowbell 0.2.7.1 places a zero-length directory name in the LD_LIBRARY_PATH, which allows local users to gain privileges via a Trojan horse shared library in the current working directory.
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Analysis
by VulDB Data Team • 02/07/2019
The vulnerability identified as CVE-2010-3353 affects the Cowbell software version 0.2.7.1 and represents a privilege escalation flaw stemming from improper handling of the LD_LIBRARY_PATH environment variable. This issue occurs when the application processes a zero-length directory name within the library path, creating an exploitable condition that can be leveraged by local attackers to execute arbitrary code with elevated privileges. The flaw resides in how the software manages dynamic library loading mechanisms and demonstrates a classic example of insecure library path handling that has been documented in various security frameworks including CWE-427 and CWE-428.
The technical implementation of this vulnerability exploits the fundamental behavior of Unix-like operating systems where the LD_LIBRARY_PATH environment variable controls the search order for shared libraries. When a zero-length directory name is present in this path, the system interprets it as the current working directory, which creates a dangerous condition where malicious actors can place Trojan horse shared libraries in the current directory and have them loaded before legitimate system libraries. This behavior aligns with ATT&CK technique T1068 which covers privilege escalation through the exploitation of dynamic link library loading mechanisms. The vulnerability specifically targets the library loading process and bypasses normal security controls by leveraging the inherent trust placed in the current working directory during library resolution.
The operational impact of this vulnerability extends beyond simple privilege escalation as it represents a significant security weakness that can be exploited by local users without requiring special permissions or network access. Attackers can simply place a malicious shared library file in the current working directory of a target process that is vulnerable to this flaw, effectively allowing them to inject arbitrary code execution capabilities. This creates a persistent threat vector where attackers can maintain access and potentially escalate privileges to root or administrative levels depending on the target process and system configuration. The vulnerability also demonstrates the importance of proper input validation and environment variable handling in security-sensitive applications.
Mitigation strategies for CVE-2010-3353 should focus on eliminating the zero-length directory from LD_LIBRARY_PATH and implementing proper library loading practices. System administrators should ensure that applications do not accept untrusted input that could modify environment variables, particularly those related to library loading. The recommended approach includes patching the vulnerable Cowbell software to version 0.2.7.2 or later, which should address the library path handling issue. Additionally, implementing security controls such as setting restrictive permissions on the current working directory, using secure library loading practices, and employing runtime monitoring tools can help prevent exploitation attempts. Organizations should also consider implementing principle of least privilege concepts and regularly auditing environment variable configurations to prevent similar vulnerabilities from being introduced through other software components. The vulnerability underscores the critical need for proper environment variable sanitization and secure coding practices in preventing privilege escalation attacks.