CVE-2016-9151 in PAN-OS
Summary
by MITRE
Palo Alto Networks PAN-OS before 5.0.20, 5.1.x before 5.1.13, 6.0.x before 6.0.15, 6.1.x before 6.1.15, 7.0.x before 7.0.11, and 7.1.x before 7.1.6 allows local users to gain privileges via crafted values of unspecified environment variables.
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Analysis
by VulDB Data Team • 11/29/2024
The vulnerability identified as CVE-2016-9151 represents a critical local privilege escalation flaw affecting Palo Alto Networks PAN-OS versions across multiple release branches. This issue stems from improper handling of environment variables within the operating system framework, creating a pathway for local attackers to elevate their privileges from standard user level to administrative access. The affected versions span across PAN-OS 5.0 through 7.1 release lines, indicating a prolonged period of vulnerability that could have been exploited by adversaries with local access to impacted systems.
The technical flaw manifests through crafted values of unspecified environment variables that are processed by the PAN-OS kernel or system services. When these variables contain maliciously constructed data, the system fails to properly validate or sanitize the inputs before using them in privilege-sensitive operations. This validation failure creates an environment where an attacker can manipulate the execution context of system processes to gain elevated privileges. The vulnerability operates at the system level rather than through network-based attacks, making it particularly dangerous as it requires only local access to exploit.
From an operational impact perspective, this vulnerability poses significant risks to organizations relying on Palo Alto Networks firewalls and next-generation security platforms. Local privilege escalation allows attackers who have already gained access to a system to elevate their privileges without requiring additional authentication or network-based attack vectors. The implications extend beyond simple privilege elevation, as administrative access to firewall systems provides complete control over network security policies, traffic inspection capabilities, and access to sensitive network infrastructure. Organizations with multiple PAN-OS devices across their network infrastructure face compounded risk, as exploitation on one device could potentially provide a foothold for broader network compromise.
The vulnerability aligns with CWE-20, "Improper Input Validation," and demonstrates characteristics consistent with privilege escalation vulnerabilities in operating system components. From an attack perspective, this flaw maps to techniques described in the MITRE ATT&CK framework under privilege escalation tactics, specifically focusing on local persistence and privilege escalation through environment variable manipulation. The attack vector requires local system access, which could be achieved through various initial compromise methods such as credential theft, phishing attacks, or exploitation of other vulnerabilities that provide local execution capabilities.
Organizations should implement immediate remediation through patch management processes to upgrade to the affected PAN-OS versions that contain the necessary security fixes. The recommended solution involves upgrading to PAN-OS 5.0.20, 5.1.13, 6.0.15, 6.1.15, 7.0.11, or 7.1.6 respectively, depending on the current version in use. Security teams should also conduct comprehensive vulnerability assessments to identify systems running affected versions and implement additional monitoring for suspicious process execution or environment variable modifications. Network segmentation and principle of least privilege should be reinforced to minimize the impact of potential exploitation even if local access is gained. Regular security assessments and continuous monitoring of system integrity remain essential to detect and prevent unauthorized privilege escalation attempts.