CVE-2018-5376 in DiscuzX
Summary
by MITRE
Discuz! DiscuzX X3.4 has XSS via the include\spacecp\spacecp_upload.php op parameter.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 12/23/2019
The vulnerability identified as CVE-2018-5376 affects Discuz! DiscuzX version X3.4 and represents a cross-site scripting flaw that arises from improper input validation within the upload control panel component. This security weakness specifically manifests through the op parameter in the include\spacecp\spacecp_upload.php file, creating an avenue for malicious actors to inject arbitrary JavaScript code into the application's response. The vulnerability falls under the category of CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a fundamental web application security issue that enables attackers to execute malicious scripts in the context of the victim's browser.
The technical implementation of this vulnerability occurs when the application processes the op parameter without adequate sanitization or encoding of user-supplied input. When a user submits a request containing malicious code within the op parameter, the Discuz! application fails to properly escape or validate this input before incorporating it into dynamically generated web pages. This allows an attacker to craft a malicious payload that, when executed in a victim's browser, can perform actions such as stealing session cookies, redirecting users to malicious sites, or executing unauthorized commands on behalf of the authenticated user. The flaw specifically impacts the space control panel functionality, which is commonly used by registered users to manage their personal content and media uploads.
The operational impact of CVE-2018-5376 extends beyond simple script execution as it can enable a wide range of malicious activities within the context of the compromised user's session. An attacker could leverage this vulnerability to hijack user sessions, access private content, modify user profiles, or even escalate privileges within the application's permission structure. The attack vector requires minimal user interaction beyond visiting a maliciously crafted link, making it particularly dangerous in social engineering scenarios. This vulnerability aligns with ATT&CK technique T1566.001 - Phishing: Spearphishing Attachment, as it can be exploited through malicious file uploads or crafted web links that trigger the XSS payload. The impact is particularly severe in environments where Discuz! forums serve as platforms for community interaction and content sharing, as the vulnerability could be exploited to compromise entire user bases.
Mitigation strategies for CVE-2018-5376 should focus on immediate input validation and output encoding measures. The primary fix involves implementing proper sanitization of the op parameter within the spacecp_upload.php file, ensuring that all user-supplied input is properly escaped before being rendered in web responses. This approach aligns with security best practices outlined in OWASP Top 10 2017 - A03:2017 - Injection, which emphasizes the importance of parameter validation and input sanitization. Organizations should also implement Content Security Policy headers to limit the execution of unauthorized scripts, and consider implementing web application firewalls to detect and block malicious payloads. Regular security auditing of input handling mechanisms and timely application of vendor security patches remain critical defensive measures against similar vulnerabilities in the Discuz! platform ecosystem.