CVE-2011-0902 in Sun Microsystems SunScreen Firewall
Summary
by MITRE
Multiple untrusted search path vulnerabilities in the Java Service in Sun Microsystems SunScreen Firewall on SunOS 5.9 allow local users to execute arbitrary code via a modified (1) PATH or (2) LD_LIBRARY_PATH environment variable.
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Analysis
by VulDB Data Team • 11/17/2024
The vulnerability identified as CVE-2011-0902 represents a critical untrusted search path issue within the Java Service component of Sun Microsystems SunScreen Firewall running on SunOS 5.9 operating systems. This flaw stems from improper handling of environment variables during the execution of privileged services, creating exploitable conditions that can be leveraged by local attackers to gain elevated system privileges. The vulnerability specifically affects the Java Service functionality that operates within the firewall framework, where the service process fails to properly validate or sanitize the search paths used to locate required libraries and executables.
The technical exploitation of this vulnerability occurs through manipulation of two critical environment variables: PATH and LD_LIBRARY_PATH. When a local user modifies these variables to include maliciously crafted paths ahead of legitimate system directories, the Java Service process will execute code from these attacker-controlled locations instead of the intended system binaries. This behavior directly aligns with CWE-426 Untrusted Search Path vulnerabilities, which occur when applications search for executables or libraries using paths that can be manipulated by untrusted users. The vulnerability exists because the service process does not properly validate the integrity of the search paths or enforce strict security boundaries during the execution of system components.
From an operational impact perspective, this vulnerability presents a severe threat to system security as it allows local users to escalate privileges and execute arbitrary code with the privileges of the Java Service process. The SunScreen Firewall service typically runs with elevated privileges to manage network traffic and security policies, making successful exploitation particularly dangerous. Attackers can leverage this vulnerability to install backdoors, modify firewall rules, or gain persistent access to the system. The attack vector is particularly concerning because it requires only local access, meaning that any user with login privileges can potentially exploit this weakness without requiring network access or additional authentication.
The exploitation process follows established patterns documented in various security frameworks including the ATT&CK framework's privilege escalation techniques. Local users can manipulate environment variables to redirect library loading and execution paths, effectively bypassing normal system security controls. This vulnerability demonstrates the importance of proper environment variable sanitization and the principle of least privilege in service design. The SunOS 5.9 operating system environment, combined with the specific Java Service implementation, creates a perfect storm where the combination of legacy security practices and improper environment handling leads to exploitable conditions.
Mitigation strategies for this vulnerability should focus on implementing proper environment variable validation and sanitization within the Java Service process. System administrators should ensure that the PATH and LD_LIBRARY_PATH variables are properly configured with secure search paths that prioritize system directories over user-controlled locations. The recommended approach includes implementing strict path validation mechanisms that prevent modification of critical environment variables during service execution. Additionally, privilege separation and least privilege principles should be enforced to minimize the impact of potential exploitation. System updates and patches from Sun Microsystems should be applied immediately to address this vulnerability, as the flaw represents a fundamental security weakness in the service execution model. Organizations should also implement monitoring for unauthorized environment variable modifications and establish proper access controls to limit local user privileges where possible.