CVE-2019-18375 in ProxySG
Summary
by MITRE
The ASG and ProxySG management consoles are susceptible to a session hijacking vulnerability. A remote attacker, with access to the appliance management interface, can hijack the session of a currently logged-in user and access the management console.
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Analysis
by VulDB Data Team • 04/10/2020
The vulnerability identified as CVE-2019-18375 affects the Application Security Gateway (ASG) and ProxySG management consoles, representing a critical session hijacking flaw that compromises the integrity of administrative access controls. This vulnerability resides within the authentication and session management mechanisms of the Palo Alto Networks security appliances, specifically targeting the web-based management interfaces that administrators use to configure and monitor these critical security devices. The flaw allows remote attackers who have already gained access to the appliance management interface to exploit session tokens and impersonate legitimate users, effectively bypassing normal authentication procedures and gaining unauthorized administrative privileges.
The technical implementation of this vulnerability stems from inadequate session management practices within the web application framework of the management consoles. When users authenticate to the ASG or ProxySG interfaces, the system generates session tokens that should remain unique and secure throughout the user's administrative session. However, the vulnerability allows an attacker with access to the management interface to extract or manipulate these session identifiers, enabling them to establish a new session with the privileges of the target user. This weakness aligns with CWE-384, which addresses session management vulnerabilities where applications fail to properly handle session identifiers, and represents a significant deviation from secure coding practices that should ensure session tokens remain unpredictable and time-bound.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it can lead to complete compromise of the security appliance and potentially the entire network infrastructure it protects. An attacker who successfully hijacks an administrative session gains full control over the appliance configuration, including the ability to modify firewall rules, alter security policies, disable logging, and redirect traffic. This vulnerability is particularly dangerous because it operates at the management layer, meaning that even if the appliance's core security functions remain intact, the attacker can effectively neutralize the device's protective capabilities. The attack vector requires only access to the management interface, which may be exposed to the internet or accessible through compromised internal network access, making the exploitation relatively straightforward for determined attackers. According to ATT&CK framework, this vulnerability maps to T1566.002 for initial access through credential manipulation and T1078.004 for legitimate credentials, as the hijacking process leverages existing authenticated sessions rather than brute force attacks.
Mitigation strategies for CVE-2019-18375 should focus on strengthening session management practices and implementing additional access controls around the management interfaces. Organizations must ensure that management interfaces are not exposed to untrusted networks and should be restricted to specific IP addresses or network segments. Implementing robust session timeout mechanisms, generating cryptographically secure session tokens, and enforcing proper session invalidation after logout are essential defensive measures. Network segmentation should separate management traffic from production traffic, and multi-factor authentication should be implemented for all administrative access points. Additionally, regular monitoring of session activity and implementation of intrusion detection systems that can identify suspicious session behavior will help detect potential exploitation attempts. The vulnerability also underscores the importance of keeping security appliances updated with the latest patches and following the principle of least privilege when configuring management access, as this flaw can be exploited by attackers who have already gained some level of access to the system.