CVE-2016-8999 in InfoSphere Information Server
Summary
by MITRE
IBM InfoSphere Information Server contains a Path-relative stylesheet import vulnerability that allows attackers to render a page in qirks mode thereby facilitating an attacker to inject malicious CSS.
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Analysis
by VulDB Data Team • 11/11/2022
The vulnerability identified as CVE-2016-8999 affects IBM InfoSphere Information Server, a data integration and governance platform widely used in enterprise environments. This security flaw resides in the application's handling of stylesheet imports, specifically when processing path-relative references within web content. The vulnerability manifests when the application fails to properly sanitize or validate stylesheet import paths, creating an opportunity for malicious actors to manipulate the rendering behavior of web pages through crafted CSS references.
This particular weakness represents a path-relative stylesheet import vulnerability that enables attackers to influence how web browsers interpret and render content. When an attacker can control or manipulate stylesheet import paths, they gain the ability to force browsers into quirks mode, a legacy rendering behavior that bypasses modern web standards and security controls. The transition to quirks mode occurs when the browser encounters malformed or improperly structured CSS references that cause it to abandon standards-compliant rendering in favor of older, less secure behaviors. This fundamental change in browser behavior creates a window of opportunity for attackers to inject malicious CSS code that would otherwise be blocked or filtered under normal rendering conditions.
The operational impact of this vulnerability extends beyond simple aesthetic manipulation, as it provides attackers with a potential foothold for more sophisticated attacks. By forcing pages into quirks mode, malicious actors can bypass certain security mechanisms that rely on standard browser rendering behaviors, potentially enabling cross-site scripting attacks, content injection, or other forms of malicious code execution. The vulnerability is particularly concerning in enterprise environments where InfoSphere Information Server handles sensitive data and complex web applications, as it could allow attackers to manipulate user interfaces or inject content that might be trusted by users or applications.
From a security framework perspective, this vulnerability aligns with CWE-20, which describes improper input validation, and CWE-116, which addresses improper encoding or escaping of output. The issue also maps to attack techniques described in the MITRE ATT&CK framework under T1059 for command and scripting interpreter and T1566 for credential harvesting through social engineering. Organizations using IBM InfoSphere Information Server should consider implementing comprehensive input validation controls, proper content security policy enforcement, and regular security assessments to address this vulnerability. The recommended mitigations include updating to patched versions of the software, implementing strict validation of all stylesheet import paths, and deploying web application firewalls that can detect and block suspicious stylesheet references. Additionally, security teams should monitor for anomalous behavior in web applications that might indicate exploitation attempts, as the vulnerability's impact is most severe when combined with other attack vectors that can leverage the quirks mode rendering behavior for more extensive compromise.