CVE-2019-19984 in Email Subscribers
Summary
by MITRE
The WordPress plugin, Email Subscribers & Newsletters, before 4.2.3 had a flaw that allowed users with edit_post capabilities to manage plugin settings and email campaigns.
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Analysis
by VulDB Data Team • 03/17/2024
The vulnerability identified as CVE-2019-19984 affects the Email Subscribers & Newsletters WordPress plugin, which is widely used for managing email marketing campaigns and subscriber lists. This plugin serves as a critical component for website administrators who rely on automated email communications to engage with their audience. The flaw exists in versions prior to 4.2.3 and represents a significant security weakness that undermines the integrity of WordPress site configurations. The vulnerability specifically targets the plugin's permission system, creating an unauthorized access vector that allows malicious actors with relatively low-level privileges to escalate their privileges within the email marketing system. This issue directly impacts the principle of least privilege that should govern access to administrative functions within WordPress ecosystems.
The technical flaw manifests through inadequate access control mechanisms within the plugin's settings management interface. Users who possess only edit_post capabilities, which is a standard permission level for content editors and contributors, can exploit this vulnerability to gain unauthorized access to plugin configuration settings and email campaign management functions. This represents a classic privilege escalation vulnerability where lower-privilege users can perform actions typically restricted to administrators or users with higher permission levels. The vulnerability stems from improper validation of user permissions when accessing plugin administrative endpoints, allowing unauthorized users to bypass standard access controls that should prevent non-administrative users from modifying core plugin functionality. This weakness aligns with CWE-284, which addresses improper access control, and demonstrates how insufficient authorization checks can lead to serious security implications.
The operational impact of this vulnerability extends beyond simple unauthorized access to potentially compromise entire email marketing campaigns and subscriber data. Attackers who exploit this vulnerability can manipulate email templates, modify subscriber lists, alter campaign scheduling, and potentially exfiltrate sensitive user information from the plugin's database. The ability to manage email campaigns with edit_post capabilities means that malicious users could send spam emails, modify existing campaigns to include malicious links, or completely disrupt email marketing operations. This vulnerability particularly affects websites that rely heavily on email automation for customer engagement, newsletter distribution, and automated marketing workflows. The risk is amplified because the affected users typically have legitimate access to the WordPress site, making the exploitation less detectable and more dangerous than attacks requiring external compromise. This scenario represents a significant concern for organizations that depend on WordPress for business-critical communications.
Mitigation strategies for CVE-2019-19984 require immediate action to update the Email Subscribers & Newsletters plugin to version 4.2.3 or later, which contains the necessary access control fixes. System administrators should conduct thorough security audits of their WordPress installations to identify all instances of the vulnerable plugin and ensure proper patching across all environments. The remediation process should include verifying that user roles and capabilities are properly configured to prevent unauthorized access to plugin administrative functions. Organizations should implement regular security monitoring to detect potential exploitation attempts and establish automated patch management processes to prevent similar vulnerabilities from affecting other plugins. Security teams should also review WordPress user permissions and ensure that only trusted administrators have access to plugin management interfaces. This vulnerability highlights the importance of maintaining up-to-date plugins and following security best practices such as implementing role-based access control and regularly auditing user permissions. The fix implemented in version 4.2.3 addresses the core access control issue by properly validating user capabilities before allowing access to administrative plugin functions, aligning with ATT&CK technique T1078 for legitimate credentials and privilege escalation.