CVE-2017-8897 in IPS
Summary
by MITRE
Invision Power Services (IPS) Community Suite 4.1.19.2 and earlier has pre-auth reflected XSS in the IPS UTF8 Converter v1.1.18: admin/convertutf8/index.php?controller= is the attack vector. This UTF8 Converter vulnerability can easily be used to make a malicious announcement affecting any Invision Power Board user who views the announcement.
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Analysis
by VulDB Data Team • 09/25/2020
The vulnerability identified as CVE-2017-8897 affects Invision Power Services (IPS) Community Suite versions 4.1.19.2 and earlier, specifically targeting the UTF8 Converter component known as v1.1.18. This security flaw represents a pre-authentication reflected cross-site scripting vulnerability that allows attackers to inject malicious scripts into web pages viewed by users. The attack vector is particularly concerning as it leverages the administrative conversion utility located at admin/convertutf8/index.php?controller= which can be accessed without prior authentication, making the exploit surface more accessible to potential attackers. The vulnerability resides within the application's handling of user-supplied input during the UTF8 conversion process, where insufficient input validation and output encoding allow malicious payloads to be reflected back to users browsing the affected pages.
The technical implementation of this vulnerability follows the typical reflected XSS pattern where user-controllable parameters are directly included in the web response without proper sanitization or encoding. When an attacker crafts a malicious URL containing script payloads and tricks users into accessing it, the application processes the input through the vulnerable UTF8 converter and reflects the malicious content back to the victim's browser. This creates a persistent threat vector that can be exploited across the entire community suite, as the vulnerability affects the core conversion utility that handles text encoding operations. The impact extends beyond simple script execution to include potential session hijacking, credential theft, and redirection to malicious sites, particularly since the vulnerability affects the administrative interface where sensitive operations occur.
The operational impact of CVE-2017-8897 is significant for organizations using Invision Power Board community platforms, as it enables attackers to execute arbitrary code in the context of a victim's browser session. The vulnerability's pre-authentication nature means that no user credentials are required to exploit the flaw, making it particularly dangerous for community platforms where users frequently interact with announcements and forum posts. When combined with the administrative access point, this vulnerability could allow attackers to escalate privileges or manipulate system functionality through malicious announcements that appear legitimate to users. The reflected nature of the vulnerability means that the attack payload is immediately executed upon page load, providing attackers with real-time exploitation capabilities and reducing the complexity of successful attacks. This vulnerability directly maps to CWE-79 which defines Cross-Site Scripting as a weakness where untrusted data is sent to a web browser without proper validation or encoding, and aligns with ATT&CK technique T1059.007 for Scripting through the execution of malicious scripts within user browsers.
Mitigation strategies for CVE-2017-8897 should focus on immediate patching of the Invision Power Board software to version 4.1.20 or later, which contains the necessary fixes for the reflected XSS vulnerability. Organizations should also implement input validation and output encoding measures at the application level to prevent malicious payloads from being processed through the UTF8 conversion utility. Network-level protections such as web application firewalls can provide additional defense-in-depth by filtering suspicious input patterns and preventing exploitation attempts. Security monitoring should be enhanced to detect unusual access patterns to the vulnerable admin/convertutf8/index.php endpoint, while user education regarding suspicious links and announcements should be reinforced. Regular security assessments of community platform components are essential to identify similar vulnerabilities in other administrative utilities, and implementing proper access controls to restrict unnecessary administrative functionality can further reduce the attack surface. The vulnerability underscores the importance of maintaining up-to-date software versions and implementing robust input validation mechanisms to prevent reflected XSS attacks that can compromise entire user communities.