CVE-2017-7945 in PAN-OS
Summary
by MITRE
The GlobalProtect external interface in Palo Alto Networks PAN-OS before 6.1.17, 7.x before 7.0.15, 7.1.x before 7.1.9, and 8.x before 8.0.2 provides different error messages for failed login attempts depending on whether the username exists, which allows remote attackers to enumerate account names and conduct brute-force attacks via a series of requests, aka PAN-SA-2017-0014 and PAN-72769.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/22/2020
The vulnerability identified as CVE-2017-7945 represents a critical information disclosure flaw in Palo Alto Networks PAN-OS firewall software affecting multiple version ranges including pre-6.1.17, pre-7.0.15, pre-7.1.9, and pre-8.0.2 releases. This vulnerability specifically impacts the GlobalProtect external interface which serves as the remote access gateway for secure network connections. The flaw stems from inconsistent error messaging mechanisms that reveal whether a username exists within the system during authentication attempts, creating a significant security risk for organizations relying on these network security appliances.
The technical implementation of this vulnerability exploits the difference in error responses between valid and invalid authentication attempts. When an attacker submits a login request, the system provides distinct error messages depending on whether the username exists in the directory or not. This behavior enables attackers to perform account enumeration by systematically testing usernames and observing the different error responses. The vulnerability operates at the authentication layer where proper security practices dictate that authentication systems should provide uniform error responses regardless of whether the username or password is incorrect, thereby preventing information leakage about system internals.
This flaw directly maps to CWE-200, which describes information exposure through error messages, and also aligns with ATT&CK technique T1110.001 for credential access through password guessing. The operational impact of this vulnerability extends beyond simple account enumeration as it enables attackers to conduct systematic brute-force attacks against the GlobalProtect interface. The ability to identify valid usernames significantly reduces the complexity of subsequent authentication attacks, making credential compromise more likely and faster to achieve. Organizations with exposed GlobalProtect interfaces become vulnerable to automated attack tools that can quickly identify valid accounts and then attempt password guessing or credential stuffing attacks.
The security implications of this vulnerability are particularly severe in environments where the GlobalProtect interface is exposed to external networks or where organizations maintain large user directories. Attackers can leverage this information to focus their efforts on specific targets, reducing the overall attack surface and increasing the probability of successful compromise. The vulnerability affects not only the immediate authentication process but also undermines the fundamental security principle of least information disclosure, where systems should reveal minimal information about their internal state to prevent attackers from gaining intelligence about valid accounts and system configuration.
Organizations should implement immediate mitigations including applying the relevant PAN-OS patches and updates released by Palo Alto Networks to address this vulnerability. Network segmentation and access controls should be enforced to limit exposure of the GlobalProtect interface to trusted networks only. Additionally, organizations should implement rate limiting and account lockout mechanisms to prevent automated brute-force attacks even if account enumeration becomes possible. The remediation process should include thorough testing of the updated systems to ensure that the error messaging behavior has been corrected and that all authentication responses provide consistent feedback to prevent future enumeration attacks.