CVE-2017-17091 in WordPress
Summary
by MITRE
wp-admin/user-new.php in WordPress before 4.9.1 sets the newbloguser key to a string that can be directly derived from the user ID, which allows remote attackers to bypass intended access restrictions by entering this string.
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Analysis
by VulDB Data Team • 01/16/2023
The vulnerability identified as CVE-2017-17091 affects WordPress versions prior to 4.9.1 and specifically targets the wp-admin/user-new.php file. This issue represents a critical access control flaw that undermines the security mechanisms designed to protect user account creation and management within the WordPress administrative interface. The vulnerability stems from the predictable nature of the newbloguser key generation process, which creates a direct mathematical relationship between user identifiers and the generated keys.
The technical flaw lies in the implementation of the newbloguser key generation algorithm where the system uses a string that can be directly computed from the user ID without proper cryptographic randomness or entropy. This predictable key generation mechanism allows unauthorized attackers to bypass intended access restrictions by simply calculating the appropriate key value based on the target user ID. The vulnerability essentially provides a backdoor mechanism where attackers can manipulate the user creation process and potentially gain unauthorized access to administrative functions.
From an operational impact perspective, this vulnerability enables remote attackers to perform unauthorized user account manipulations and access control bypasses without requiring valid authentication credentials. The flaw can be exploited to create or modify user accounts with elevated privileges, potentially leading to complete administrative compromise of the WordPress installation. Security researchers have classified this as a privilege escalation vulnerability that can be leveraged to gain unauthorized access to sensitive administrative functions, making it particularly dangerous for organizations relying on WordPress for their web presence.
The vulnerability aligns with CWE-330 weakness category, which focuses on the use of insufficiently random values, and represents a specific instance of weak cryptographic key generation. It also maps to ATT&CK technique T1078.004, which covers valid accounts with compromised credentials, as attackers can exploit this weakness to gain access to legitimate administrative accounts through predictable key manipulation. Organizations should immediately update to WordPress version 4.9.1 or later to address this vulnerability, as the patch implements proper cryptographic randomization for the newbloguser key generation process, eliminating the predictable pattern that made exploitation possible. Additionally, implementing proper access controls, monitoring user account creation activities, and maintaining up-to-date security practices remain essential defensive measures against similar vulnerabilities.