CVE-2017-5328 in Terminal Services Agent
Summary
by MITRE
Palo Alto Networks Terminal Services Agent before 7.0.7 allows attackers to spoof arbitrary users via unspecified vectors.
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Analysis
by VulDB Data Team • 05/16/2026
The vulnerability identified as CVE-2017-5328 affects Palo Alto Networks Terminal Services Agent versions prior to 7.0.7, presenting a critical security flaw that enables unauthorized user spoofing. This vulnerability resides within the authentication and authorization mechanisms of the terminal services component, which is integral to network access control and user management. The unspecified vectors suggest that attackers can exploit multiple pathways to achieve user impersonation, making the vulnerability particularly concerning for organizations relying on these security controls for network segmentation and access management.
The technical flaw manifests in the improper handling of authentication tokens or session identifiers within the Terminal Services Agent implementation. This weakness allows malicious actors to craft forged authentication requests that bypass normal user verification processes, effectively enabling them to assume the identity of any valid user within the system. The vulnerability's impact extends beyond simple unauthorized access, as successful exploitation can lead to privilege escalation and lateral movement within the network infrastructure. According to CWE classification, this vulnerability aligns with CWE-287 which addresses improper authentication issues, and potentially CWE-305 which covers authentication bypass through use of weak authentication mechanisms.
Operationally, this vulnerability poses significant risks to organizations utilizing Palo Alto Networks firewalls and security appliances that depend on Terminal Services Agent for remote access management. Attackers could leverage this flaw to gain unauthorized access to network resources, potentially compromising sensitive data and system integrity. The spoofing capability enables persistent access to systems, as attackers can maintain their impersonated identities without detection. This vulnerability particularly affects environments where terminal services are used for administrative access, remote desktop connections, or VPN services, creating attack vectors for advanced persistent threats and insider threat scenarios. The exploitation of this vulnerability can result in complete compromise of network access controls, undermining the fundamental security posture of organizations relying on these devices.
Organizations should immediately implement mitigations including upgrading to Palo Alto Networks Terminal Services Agent version 7.0.7 or later, which contains the necessary patches to address the authentication spoofing vulnerability. Network segmentation and additional authentication controls should be implemented as defensive measures, including multi-factor authentication for terminal services access and monitoring for suspicious authentication patterns. Security teams should conduct comprehensive vulnerability assessments to identify systems running affected versions and establish network monitoring procedures to detect potential exploitation attempts. According to ATT&CK framework, this vulnerability maps to T1078 which covers valid accounts and T1566 which covers credential harvesting, highlighting the need for both preventive and detective security controls to protect against exploitation attempts.