CVE-2017-14331 in EXOS
Summary
by MITRE
Extreme EXOS 16.x, 21.x, and 22.x allows administrators to bypass the "exsh restricted shell" protection mechanism and obtain an interactive shell.
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Analysis
by VulDB Data Team • 11/30/2019
The vulnerability identified as CVE-2017-14331 represents a critical authorization bypass flaw in Extreme Networks EXOS operating systems affecting versions 16.x, 21.x, and 22.x. This security weakness specifically targets the exsh restricted shell protection mechanism that is designed to limit administrative access to only authorized commands and prevent unauthorized system interactions. The flaw allows malicious actors or compromised administrators to circumvent the intended security controls and gain full interactive shell access to the affected systems.
The technical implementation of this vulnerability stems from improper validation of shell command execution within the EXOS operating system framework. When administrators attempt to execute commands through the restricted shell environment, the system fails to properly enforce the security boundaries that should prevent access to privileged shell functionalities. This oversight creates an exploitable path where the restricted shell protection can be bypassed through carefully crafted command sequences or by leveraging specific command execution flows that were not adequately constrained by the security model.
From an operational impact perspective, this vulnerability poses significant risks to network infrastructure security as it allows for complete system compromise. An attacker who successfully exploits this vulnerability can execute arbitrary commands with the privileges of the administrative account, potentially leading to full system control, data exfiltration, network reconnaissance, and lateral movement within the affected network segments. The restricted shell mechanism was specifically designed to prevent such scenarios, making this bypass particularly concerning as it undermines fundamental security controls that organizations rely upon for protecting critical network infrastructure.
Organizations running affected EXOS versions should immediately implement mitigations including applying the vendor-provided security patches, reviewing and tightening administrative access controls, monitoring for suspicious command execution patterns, and implementing additional network segmentation measures. The vulnerability aligns with CWE-284 which addresses improper access control, and maps to ATT&CK techniques related to privilege escalation and command execution. Network administrators should also consider implementing comprehensive audit logging to detect unauthorized shell access attempts and establish baseline behavioral patterns to identify potential exploitation of this vulnerability.
The broader implications of this vulnerability highlight the importance of proper privilege separation and the need for robust security controls in network operating systems. It demonstrates how a single flaw in shell protection mechanisms can completely undermine administrative security models and emphasizes the critical requirement for thorough security testing of privileged access controls in enterprise network infrastructure. Organizations should conduct immediate vulnerability assessments to identify all affected systems and implement layered security approaches that do not rely solely on a single protection mechanism for critical administrative functions.