CVE-2006-4842 in Solaris
Summary
by MITRE
The Netscape Portable Runtime (NSPR) API 4.6.1 and 4.6.2, as used in Sun Solaris 10, trusts user-specified environment variables for specifying log files even when running from setuid programs, which allows local users to create or overwrite arbitrary files.
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Analysis
by VulDB Data Team • 04/24/2026
The vulnerability identified as CVE-2006-4842 represents a critical security flaw in the Netscape Portable Runtime API version 4.6.1 and 4.6.2 implementations found in Sun Solaris 10 systems. This issue stems from improper handling of environment variables within setuid programs, creating a dangerous privilege escalation vector that can be exploited by local attackers to manipulate system files. The NSPR API serves as a foundational runtime library for many applications, including those that require elevated privileges to function correctly within the Solaris operating system environment.
The technical flaw manifests when setuid programs that utilize the NSPR API read user-specified environment variables to determine log file locations without proper validation or sanitization. This behavior violates fundamental security principles by allowing untrusted input to dictate file system operations, even in privileged contexts where such operations should be strictly controlled and validated. The vulnerability specifically affects the logging functionality within the NSPR API, where environment variables such as NSPR_LOG_FILE or similar logging parameters are interpreted without adequate access control checks. When these programs execute with elevated privileges, the user-controlled file paths can be manipulated to point to arbitrary system locations, enabling file creation or overwrites that would otherwise be prohibited.
The operational impact of this vulnerability extends beyond simple file manipulation, as it creates a persistent threat vector for local attackers who can leverage this weakness to establish persistence within the system. An attacker could potentially overwrite critical system files, create malicious log files that could be exploited by other system components, or manipulate the logging infrastructure to hide their activities. This vulnerability is particularly concerning in enterprise environments where Solaris 10 systems may host applications that run with setuid privileges, as it provides a mechanism for attackers to gain unauthorized access to system resources and potentially escalate their privileges further. The flaw essentially allows a local user to bypass normal file system access controls and perform operations that should only be permitted to root or other privileged users.
Mitigation strategies for CVE-2006-4842 should focus on both immediate patching and operational security improvements. Organizations must prioritize updating their Solaris 10 systems to versions that include fixed NSPR API implementations, as the vulnerability cannot be effectively addressed through configuration changes alone. System administrators should implement strict environment variable validation mechanisms within setuid programs to prevent user-controlled input from influencing file system operations. This aligns with security best practices outlined in the CWE-22 category, which addresses "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')" and the ATT&CK framework's privilege escalation techniques. Additionally, implementing mandatory access controls and regular security auditing of setuid programs can help identify and remediate similar vulnerabilities in the system's attack surface.