CVE-2020-9015 in DCS-7050QX-32S-R
Summary
by MITRE
Arista DCS-7050QX-32S-R 4.20.9M, DCS-7050CX3-32S-R 4.20.11M, and DCS-7280SRAM-48C6-R 4.22.0.1F devices allow attackers to bypass intended TACACS+ shell restrictions via a | character.
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Analysis
by VulDB Data Team • 08/04/2024
The vulnerability identified as CVE-2020-9015 affects Arista network switches including models DCS-7050QX-32S-R, DCS-7050CX3-32S-R, and DCS-7280SRAM-48C6-R running specific software versions. This security flaw resides in the TACACS+ authentication and authorization implementation within these network devices, creating a significant bypass opportunity for malicious actors seeking to escalate privileges and gain unauthorized access to network infrastructure. The vulnerability specifically relates to how these devices handle shell command restrictions when users authenticate via TACACS+ protocol.
The technical flaw manifests through the improper handling of the pipe character | within TACACS+ shell command restrictions. When authorized users attempt to execute commands containing this character, the system fails to properly validate or restrict the command execution, allowing attackers to bypass intended security controls. This occurs because the TACACS+ authorization mechanism does not adequately sanitize or filter command inputs that contain the pipe character, which is commonly used in shell contexts to chain commands or redirect output. The vulnerability essentially creates a path where legitimate TACACS+ authenticated users can execute arbitrary commands beyond their intended authorization scope, effectively undermining the security controls designed to limit administrative access.
The operational impact of this vulnerability is severe for network infrastructure security. Attackers who can exploit this weakness can potentially escalate privileges from standard user access to administrative control of network switches, enabling them to modify configurations, monitor traffic, or redirect network flows. This represents a critical compromise of network security posture, as these switches serve as fundamental components in network architecture where unauthorized access could lead to widespread disruption or data breaches. The vulnerability affects devices that are commonly deployed in enterprise and data center environments where network switches are critical to infrastructure operations and security.
Organizations should immediately implement mitigations including updating to patched firmware versions provided by Arista, which address the TACACS+ command validation issue. Network administrators should also review and tighten TACACS+ authorization policies to minimize the scope of commands that can be executed by users with elevated privileges. The vulnerability aligns with CWE-20 Improper Input Validation, which specifically addresses the failure to properly validate input data that can lead to command injection and privilege escalation. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and command execution, potentially enabling adversaries to establish persistent access to network infrastructure through the exploitation of authentication bypass mechanisms.
Security teams should conduct comprehensive audits of TACACS+ configurations across all affected devices, ensuring that command restrictions are properly enforced and that no unnecessary administrative privileges are granted. The mitigation approach should include implementing proper input sanitization for all shell command execution contexts and monitoring for anomalous command patterns that might indicate exploitation attempts. Regular security assessments should verify that TACACS+ authorization rules are functioning correctly and that no bypass paths exist through special characters or command chaining mechanisms. This vulnerability demonstrates the critical importance of proper input validation in network security systems and the potential for seemingly minor implementation flaws to create major security risks in enterprise infrastructure.