CVE-2010-4159 in Mono
Summary
by MITRE
Untrusted search path vulnerability in metadata/loader.c in Mono 2.8 and earlier 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 • 10/05/2021
The vulnerability described in CVE-2010-4159 represents a classic untrusted search path issue that affects the Mono runtime environment version 2.8 and earlier. This flaw exists within the metadata/loader.c component of the Mono framework, which is a cross-platform implementation of the common language runtime and the framework class library that forms the foundation of Microsoft's .NET development platform. The vulnerability arises from how the system handles dynamic library loading during the execution of managed applications, creating a potential privilege escalation vector for local attackers who can manipulate the runtime environment.
The technical flaw stems from the insecure handling of shared library loading mechanisms within the Mono runtime's loader functionality. When Mono executes applications, it searches for required shared libraries in a specific order that includes the current working directory. This search path behavior allows an attacker to place a malicious shared library with the same name as a legitimate library in the current working directory, causing the system to load the attacker-controlled code instead of the intended library. This represents a direct violation of the principle of least privilege and demonstrates a clear path for privilege escalation from a local user to a higher privilege level.
The operational impact of this vulnerability extends beyond simple local privilege escalation, as it can be exploited to execute arbitrary code with elevated privileges. Attackers can leverage this weakness to install backdoors, modify system files, or perform other malicious activities that would normally require administrative access. The vulnerability is particularly concerning because it does not require network connectivity or remote exploitation, making it an attractive target for attackers who have already gained local access to a system. This weakness can be particularly dangerous in environments where Mono applications are executed with elevated privileges or where users with lower privileges can influence the working directory of Mono processes.
The security implications of this vulnerability align with CWE-427, which describes uncontrolled search path vulnerabilities, and can be mapped to ATT&CK technique T1068, which covers local privilege escalation through exploitation of system vulnerabilities. Organizations running Mono applications are particularly at risk, especially in environments where multiple users share systems or where applications are executed with elevated permissions. The vulnerability demonstrates the importance of proper library loading practices and secure coding techniques that avoid insecure search paths. Effective mitigation strategies include updating to Mono versions 2.10 and later where this vulnerability has been addressed, implementing proper library loading mechanisms that do not include the current working directory in the search path, and ensuring that system directories are properly secured to prevent unauthorized library placement. Additionally, administrators should consider implementing application whitelisting policies and monitoring for suspicious library loading activities to detect potential exploitation attempts.