CVE-2010-4170 in SystemTap
Summary
by MITRE
The staprun runtime tool in SystemTap 1.3 does not properly clear the environment before executing modprobe, which allows local users to gain privileges by setting the MODPROBE_OPTIONS environment variable to specify a malicious configuration file.
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Analysis
by VulDB Data Team • 11/30/2024
The vulnerability identified as CVE-2010-4170 resides within the staprun runtime tool of SystemTap version 1.3, representing a critical privilege escalation flaw that exploits improper environment handling during module loading operations. This issue demonstrates a fundamental failure in secure coding practices where the staprun utility fails to properly sanitize the execution environment before invoking the modprobe command, creating a pathway for local attackers to manipulate system behavior through environment variable manipulation. The vulnerability specifically targets the MODPROBE_OPTIONS environment variable, which when improperly handled can be leveraged to inject malicious configuration directives into the module loading process.
The technical exploitation of this vulnerability occurs through a well-known privilege escalation vector that aligns with CWE-250, which addresses "Execute Code with Unusual Privileges" and CWE-78, addressing "Improper Neutralization of Special Elements used in an OS Command." When a local user sets the MODPROBE_OPTIONS environment variable to point to a malicious configuration file, the staprun tool passes this unvalidated input directly to modprobe without proper sanitization, allowing the attacker to inject arbitrary module loading parameters. This flaw is particularly dangerous because staprun typically operates with elevated privileges due to its role in system monitoring and profiling, making the privilege escalation potential significant.
The operational impact of CVE-2010-4170 extends beyond simple local privilege escalation, as it represents a classic attack pattern that aligns with techniques described in the MITRE ATT&CK framework under T1068, "Exploitation for Privilege Escalation." The vulnerability creates a persistent threat vector where an unprivileged user can effectively elevate their privileges to root level, potentially compromising the entire system. This is particularly concerning in environments where SystemTap is installed and used for performance monitoring, as the tool often requires elevated permissions to function properly, making the attack surface more accessible.
SystemTap's staprun utility serves as a bridge between user-space monitoring tools and kernel-space module management, creating a natural attack vector where environment variables can be manipulated to influence kernel behavior. The flaw demonstrates poor input validation and environment sanitization practices that are commonly addressed through secure coding guidelines and principles outlined in the OWASP Secure Coding Practices. The vulnerability's exploitation requires minimal skill level and can be automated, making it particularly dangerous in multi-user environments where privilege separation is critical. Organizations implementing SystemTap for system monitoring should consider this vulnerability as a critical security concern that could lead to complete system compromise.
Mitigation strategies for CVE-2010-4170 should focus on immediate patching of SystemTap installations to versions that properly sanitize environment variables before executing modprobe commands. Administrators should also implement restrictive file permissions on SystemTap-related binaries and consider disabling unnecessary staprun functionality in environments where privilege escalation risks are unacceptable. The vulnerability highlights the importance of environment variable validation in privilege escalation contexts and serves as a reminder of the critical need for proper input sanitization in system utilities that operate with elevated privileges. Security monitoring should include detection of suspicious MODPROBE_OPTIONS usage patterns and unauthorized changes to SystemTap configurations, as these may indicate attempted exploitation of similar vulnerabilities.