CVE-2017-15108 in spice-vdagent
Summary
by MITRE
spice-vdagent up to and including 0.17.0 does not properly escape save directory before passing to shell, allowing local attacker with access to the session the agent runs in to inject arbitrary commands to be executed.
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Analysis
by VulDB Data Team • 02/02/2023
The vulnerability identified as CVE-2017-15108 affects the spice-vdagent component version 0.17.0 and earlier, representing a critical command injection flaw that undermines the security of virtual desktop environments. This vulnerability specifically targets the virtual delivery agent used in spice virtualization platforms, where the agent operates within user sessions to facilitate clipboard sharing, file transfers, and other desktop functionalities. The flaw manifests when the agent processes save directory paths without proper sanitization, creating an avenue for malicious command execution.
The technical implementation of this vulnerability stems from insufficient input validation and improper shell command construction within the spice-vdagent binary. When users attempt to save files through the virtual desktop environment, the agent receives directory paths that should be treated as data inputs rather than executable commands. However, the agent fails to properly escape or sanitize these paths before incorporating them into shell commands, leading to potential code injection scenarios. This design flaw aligns with CWE-78, which specifically addresses improper neutralization of special elements used in OS commands, and CWE-88, concerning improper neutralization of argument delimiters in a command.
The operational impact of CVE-2017-15108 is significant for organizations utilizing spice virtualization environments, as it allows local attackers with session access to execute arbitrary commands with the privileges of the spice-vdagent process. This represents a privilege escalation vector that can potentially lead to complete system compromise, especially when the agent runs with elevated permissions. Attackers could leverage this vulnerability to install backdoors, exfiltrate data, or establish persistent access within virtual desktop environments. The vulnerability is particularly dangerous in enterprise settings where virtual desktop infrastructure (VDI) is deployed, as it could enable attackers to move laterally within the network or target specific virtual machines.
From an adversarial perspective, this vulnerability maps directly to several ATT&CK techniques including privilege escalation through command injection and execution through valid accounts. The attack chain typically begins with an attacker gaining access to a legitimate user session within the virtual desktop environment, followed by exploitation of the command injection vulnerability to execute malicious payloads. Organizations should consider this vulnerability in their threat modeling exercises, particularly when evaluating risks associated with remote desktop and virtual desktop infrastructure deployments. The vulnerability also highlights the importance of secure coding practices in agent-based systems and proper input validation mechanisms.
Mitigation strategies for CVE-2017-15108 should prioritize immediate patching of affected spice-vdagent versions to 0.17.1 or later, where the command injection flaw has been addressed through proper input sanitization and shell escaping mechanisms. Network segmentation and access controls should be implemented to limit user access to virtual desktop sessions, reducing the attack surface available to potential adversaries. Additionally, organizations should conduct regular security assessments of their virtualization environments, focusing on agent security and input validation practices. System administrators should monitor for unusual command execution patterns and implement proper logging and alerting mechanisms to detect potential exploitation attempts. The vulnerability underscores the necessity of applying security patches promptly and maintaining up-to-date virtualization infrastructure to prevent exploitation of known vulnerabilities in critical system components.