CVE-2023-45756 in ApplyOnline Plugin
Summary
by MITRE • 10/25/2023
Unauth. Reflected Cross-Site Scripting (XSS) vulnerability in Spider Teams ApplyOnline – Application Form Builder and Manager plugin
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Analysis
by VulDB Data Team • 11/16/2023
The CVE-2023-45756 vulnerability represents a critical unauthenticated reflected cross-site scripting flaw discovered in the Spider Teams ApplyOnline plugin, which serves as an Application Form Builder and Manager for WordPress environments. This vulnerability specifically affects the plugin's handling of user input parameters that are reflected back to users without proper sanitization or encoding mechanisms. The issue manifests when malicious actors craft specially formatted URLs containing script payloads that are then executed in the context of a victim's browser session. The vulnerability stems from inadequate input validation and output encoding practices within the plugin's codebase, particularly in how it processes and displays user-supplied parameters in web responses. This type of vulnerability falls under the Common Weakness Enumeration category CWE-79 which specifically addresses cross-site scripting flaws, and aligns with ATT&CK technique T1566.001 related to Spearphishing Attachments and T1566.002 for Spearphishing Links, as attackers can leverage this vulnerability to deliver malicious payloads through crafted web requests.
The technical implementation of this reflected XSS vulnerability occurs when the plugin fails to properly sanitize or encode user input parameters before incorporating them into HTML responses. Attackers can exploit this by constructing malicious URLs containing JavaScript payloads that are reflected back to unsuspecting users who click on the links. The vulnerability is particularly dangerous because it requires no authentication, making it accessible to any attacker with knowledge of the target system. The reflected nature means that the malicious script is not stored on the server but rather injected through the web application's response to a crafted request. This creates a time-sensitive attack vector where the malicious payload must be delivered immediately to the victim's browser for execution to occur successfully. The vulnerability affects WordPress installations running the Spider Teams ApplyOnline plugin version prior to the security patch release, with the exact version ranges requiring patching determined through careful analysis of the plugin's source code modifications.
The operational impact of CVE-2023-45756 extends beyond simple script execution as it provides attackers with a foothold for more sophisticated attacks within the victim's browser environment. Once a victim's browser executes the malicious script, attackers can potentially steal session cookies, perform actions on behalf of the user, redirect to malicious sites, or harvest sensitive information from the user's browsing session. The vulnerability could enable attackers to impersonate legitimate users, access restricted areas of the website, or even escalate privileges within the WordPress environment if the victim holds administrative roles. The unauthenticated nature of this vulnerability makes it particularly attractive to threat actors as it eliminates the need for prior access credentials. Additionally, the reflected nature means that attackers can leverage this vulnerability in phishing campaigns or social engineering attacks where they craft malicious links that appear legitimate to victims, potentially leading to widespread compromise across multiple user sessions.
Mitigation strategies for CVE-2023-45756 should prioritize immediate plugin updates to the latest secure versions that contain proper input sanitization and output encoding mechanisms. Organizations should implement comprehensive web application firewall rules to detect and block malicious script payloads in URL parameters, particularly focusing on common XSS attack patterns and character sequences. Input validation should be strengthened at multiple layers including application-level filtering and output encoding for all parameters that are reflected back to users. Security headers such as Content Security Policy should be implemented to limit script execution capabilities and prevent unauthorized code from running in the browser context. Regular security audits and penetration testing of WordPress installations should be conducted to identify similar vulnerabilities in other plugins or themes. The remediation process should include thorough code review of the plugin's parameter handling, implementation of proper HTML escaping for all dynamic content, and deployment of automated security monitoring to detect suspicious traffic patterns that may indicate exploitation attempts. Organizations should also consider implementing principle of least privilege for WordPress user accounts and regularly rotate administrative credentials to limit potential damage from successful exploitation attempts.