CVE-2018-5331 in DiscuzX
Summary
by MITRE
Discuz! DiscuzX X3.4 has XSS via the view parameter to include/space/space_poll.php, as demonstrated by a mod=space do=poll request to home.php.
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Analysis
by VulDB Data Team • 12/21/2019
The vulnerability CVE-2018-5331 represents a cross-site scripting flaw discovered in Discuz! DiscuzX version 3.4, specifically within the space_poll.php component. This issue arises from insufficient input validation and sanitization mechanisms that fail to properly handle user-supplied data in the view parameter. The vulnerability manifests when processing requests containing mod=space and do=poll parameters directed to the home.php endpoint, creating a pathway for malicious actors to inject and execute arbitrary JavaScript code within the context of affected user sessions.
The technical exploitation of this vulnerability stems from the application's failure to adequately sanitize or escape user input before incorporating it into dynamic web page content. When the view parameter is processed through the include/space/space_poll.php script, the system does not implement proper output encoding or validation controls that would prevent malicious payloads from being executed. This weakness directly maps to CWE-79, which defines cross-site scripting vulnerabilities as the failure to properly escape output data, and aligns with ATT&CK technique T1190, which covers exploitation of vulnerabilities in web applications through injection attacks.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking, as it enables attackers to perform a wide range of malicious activities including but not limited to cookie theft, redirection to malicious sites, defacement of user profiles, and potential privilege escalation within the forum environment. The vulnerability affects all users of the affected Discuz! version, making it particularly dangerous as it can be exploited by anyone with access to the forum's polling functionality. Successful exploitation could lead to unauthorized access to user accounts, data corruption, and compromise of the entire forum infrastructure.
Mitigation strategies for CVE-2018-5331 should include immediate application of the vendor-provided security patch, which typically involves implementing proper input validation and output encoding mechanisms. Organizations should also consider implementing web application firewalls to detect and block malicious payloads, establishing robust content security policies to prevent script execution, and conducting regular security assessments of web applications. Additionally, developers should follow secure coding practices such as implementing proper parameter validation, using context-specific output encoding, and maintaining up-to-date security libraries to prevent similar vulnerabilities from occurring in future versions. The vulnerability underscores the critical importance of input sanitization and output encoding in preventing injection-based attacks, aligning with industry best practices outlined in OWASP Top Ten and other security frameworks.