CVE-2011-1129 in SMF
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the EditNews function in ManageNews.php in Simple Machines Forum (SMF) before 1.1.13, and 2.x before 2.0 RC5, might allow remote authenticated users to inject arbitrary web script or HTML via a save_items action.
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Analysis
by VulDB Data Team • 02/09/2019
The vulnerability CVE-2011-1129 represents a critical cross-site scripting flaw discovered in Simple Machines Forum software versions prior to 1.1.13 and 2.x before 2.0 RC5. This vulnerability specifically targets the EditNews function within the ManageNews.php file, creating a pathway for malicious actors to execute arbitrary web scripts or HTML code within the context of affected user sessions. The flaw operates as a remote authenticated vulnerability, meaning that attackers must first establish valid credentials to exploit the weakness, though this requirement does not significantly diminish the potential impact given the prevalence of compromised accounts in forum environments. The vulnerability stems from insufficient input validation and output encoding mechanisms within the news management functionality, allowing malicious payloads to be stored and subsequently executed when legitimate users view the affected content.
The technical exploitation of this vulnerability occurs through the save_items action parameter within the EditNews function, where user-supplied data fails to undergo proper sanitization before being rendered in web pages. This oversight creates a persistent XSS vector that can be leveraged to steal session cookies, redirect users to malicious sites, or perform unauthorized actions on behalf of authenticated users. The vulnerability aligns with CWE-79, which specifically addresses Cross-site Scripting flaws in software applications, and demonstrates how inadequate data validation can compromise web application security. Attackers can craft malicious scripts that execute in the context of other users' browsers, potentially leading to account takeover, data exfiltration, or further exploitation of the compromised forum environment. The flaw particularly affects forum administrators and moderators who have elevated privileges, as their sessions are more valuable targets for attackers seeking persistent access to sensitive administrative functions.
The operational impact of CVE-2011-1129 extends beyond simple script injection, as it can facilitate more sophisticated attacks within the forum ecosystem. When exploited, this vulnerability enables attackers to manipulate forum content, inject malicious advertisements, or redirect users to phishing sites that can harvest additional credentials. The persistent nature of stored XSS means that victims do not need to actively engage with malicious content for the attack to succeed, as the injected scripts execute automatically when the compromised page is loaded. This characteristic makes the vulnerability particularly dangerous in community-driven platforms where users frequently visit and interact with forum content. Organizations using affected SMF versions face significant risks including potential data breaches, reputational damage, and the compromise of user privacy, as attackers can exploit the vulnerability to access sensitive user information or manipulate forum content to spread malware or conduct social engineering campaigns.
Organizations should implement immediate mitigation strategies including upgrading to patched versions of Simple Machines Forum software, specifically versions 1.1.13 and 2.0 RC5 or later, which contain proper input validation and output encoding fixes for the vulnerability. Additionally, administrators should enforce strict input validation on all user-contributed content, implement Content Security Policy headers to limit script execution, and conduct regular security audits of forum functionality. The vulnerability demonstrates the importance of proper input sanitization and output encoding practices, as outlined in the OWASP Top Ten security framework and aligned with ATT&CK technique T1059 for command and scripting interpreter. Security teams should also consider implementing web application firewalls to detect and block malicious payloads attempting to exploit similar vulnerabilities, while establishing monitoring procedures to identify potential exploitation attempts through anomalous user behavior patterns or unexpected content modifications in forum environments.