CVE-2016-2985 in Spectrum Scale
Summary
by MITRE
IBM Spectrum Scale 4.1.1.x before 4.1.1.8 and 4.2.x before 4.2.0.4 and General Parallel File System (GPFS) 3.5.x before 3.5.0.32 and 4.1.x before 4.1.1.8 allow local users to gain privileges via crafted environment variables to a /usr/lpp/mmfs/bin/ setuid program.
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Analysis
by VulDB Data Team • 06/08/2019
The vulnerability identified as CVE-2016-2985 affects IBM Spectrum Scale and General Parallel File System implementations across multiple versions, specifically targeting the handling of environment variables within setuid programs. This issue represents a classic privilege escalation vector that exploits the insecure execution of privileged binaries. The affected systems include IBM Spectrum Scale versions 4.1.1.x before 4.1.1.8 and 4.2.x before 4.2.0.4, alongside GPFS versions 3.5.x before 3.5.0.32 and 4.1.x before 4.1.1.8. The vulnerability specifically involves a setuid program located at /usr/lpp/mmfs/bin/ which processes environment variables without proper sanitization or validation.
The technical flaw stems from the improper handling of environment variables within setuid contexts, creating a path for local attackers to manipulate program execution behavior. When a local user executes a setuid program located in the specified path, the program fails to properly validate or sanitize environment variables that could be modified by the user. This allows an attacker to inject malicious environment variables that influence how the program executes, potentially leading to privilege escalation. The vulnerability is categorized under CWE-276, which specifically addresses improper privileges, and represents a direct violation of secure programming practices for setuid applications. The flaw is particularly dangerous because it leverages the inherent trust placed in setuid programs to execute with elevated privileges while simultaneously allowing user-controlled input to modify program behavior.
The operational impact of this vulnerability extends beyond simple privilege escalation to potentially compromise entire file system operations and data integrity. Local users who exploit this vulnerability can gain elevated privileges that would normally be restricted, potentially allowing them to modify critical system files, access restricted data, or perform administrative functions within the GPFS or Spectrum Scale environment. The attack surface is significant since these file systems are commonly deployed in enterprise environments where data availability and integrity are paramount. The vulnerability can be exploited by any local user, making it particularly concerning for multi-user systems where privilege separation is critical for maintaining security boundaries. The attack vector requires minimal prerequisites, as it only requires local access to the system and the ability to modify environment variables, making it accessible to both casual attackers and more sophisticated threat actors.
Mitigation strategies for this vulnerability should focus on immediate patching of affected systems to the recommended versions that contain the necessary security fixes. Organizations should implement comprehensive vulnerability management processes to identify and remediate similar issues across their infrastructure. The fix typically involves proper environment variable sanitization within the setuid programs, ensuring that user-controlled inputs cannot influence program execution behavior. Security best practices should include regular auditing of setuid binaries, implementation of privilege separation mechanisms, and adherence to secure coding guidelines that prevent environment variable manipulation in privileged contexts. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be used to establish persistent access or move laterally within a compromised system. Organizations should also consider implementing additional controls such as file integrity monitoring, privileged access management, and regular security assessments to prevent similar vulnerabilities from being introduced in future deployments.