CVE-2021-24924 in Email Log Plugin
Summary
by MITRE • 12/06/2021
The Email Log WordPress plugin before 2.4.8 does not escape the d parameter before outputting it back in an attribute in the Log page, leading to a Reflected Cross-Site Scripting issue
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Analysis
by VulDB Data Team • 12/09/2021
The vulnerability identified as CVE-2021-24924 affects the Email Log WordPress plugin version 2.4.7 and earlier, representing a critical reflected cross-site scripting flaw that compromises user security. This issue stems from improper input sanitization within the plugin's Log page functionality where the d parameter remains unescaped before being rendered back in an HTML attribute. The vulnerability manifests when malicious actors craft specially crafted URLs containing script payloads in the d parameter, which are then reflected back to users browsing the email log interface.
The technical exploitation of this vulnerability occurs through a classic reflected XSS attack vector where an attacker constructs a malicious URL with encoded script content in the d parameter and delivers it to unsuspecting users via phishing emails, social engineering, or compromised websites. When a victim clicks the malicious link and navigates to the Email Log page, the unescaped d parameter value gets embedded into an HTML attribute, allowing the injected script to execute within the victim's browser context. This creates a persistent threat vector that can be leveraged for session hijacking, credential theft, or redirection to malicious sites.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to manipulate the email logging interface and potentially access sensitive email data. The reflected nature of the vulnerability means that the attack requires user interaction but does not necessitate persistent server-side modifications, making it particularly dangerous in environments where users frequently access administrative interfaces. This vulnerability directly maps to CWE-79, which categorizes cross-site scripting flaws as weaknesses in input validation and output escaping mechanisms.
Security professionals should recognize this vulnerability as a prime example of the ATT&CK technique T1566.001, specifically focusing on the initial access phase through spearphishing attachments or links. The flaw represents a failure in the principle of least privilege and proper input validation, where the plugin should have implemented proper HTML escaping or sanitization of all user-supplied parameters before rendering them in output contexts. Organizations using the Email Log plugin must immediately update to version 2.4.8 or later to mitigate this risk, as the vulnerability allows attackers to execute arbitrary JavaScript code within the context of authenticated users' browsers.
Mitigation strategies should include immediate plugin updates, implementation of web application firewalls to detect and block malicious payloads, and regular security auditing of WordPress plugins for similar input validation issues. The vulnerability underscores the critical importance of proper output escaping in web applications, particularly when dealing with user-controllable parameters that may be rendered in HTML attributes. Security teams should also consider implementing Content Security Policy headers as an additional defensive measure to limit the impact of potential XSS exploitation attempts and establish comprehensive monitoring for suspicious user behavior patterns that may indicate exploitation attempts.