CVE-2015-6515 in Splunk
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Splunk Web in Splunk Enterprise 6.2.x before 6.2.4, 6.1.x before 6.1.8, 6.0.x before 6.0.9, and 5.0.x before 5.0.13 and Splunk Light 6.2.x before 6.2.4 allows remote attackers to inject arbitrary web script or HTML via a header.
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Analysis
by VulDB Data Team • 06/12/2022
The CVE-2015-6515 vulnerability represents a critical cross-site scripting flaw in Splunk Web that affected multiple versions of Splunk Enterprise and Splunk Light products. This vulnerability resides in the web interface component of Splunk, which serves as the primary user interaction point for managing and analyzing data within the Splunk platform. The flaw specifically manifests in how the web interface processes HTTP headers, creating an avenue for remote attackers to inject malicious scripts or HTML code into the application's response. The vulnerability impacts versions ranging from 5.0.0 through 5.0.12, 6.0.0 through 6.0.8, 6.1.0 through 6.1.7, and 6.2.0 through 6.2.3, making it a widespread issue affecting a significant portion of Splunk's user base during that time period.
The technical exploitation of this vulnerability occurs through manipulation of HTTP headers that are processed by Splunk Web's input validation mechanisms. When an attacker crafts malicious headers containing script tags or other HTML content, the vulnerable Splunk Web interface fails to properly sanitize these inputs before rendering them in the browser context. This failure to implement proper input validation and output encoding creates a persistent XSS vector that allows attackers to execute arbitrary JavaScript code within the context of a victim's browser session. The vulnerability is classified as a classic reflected XSS issue where attacker-controlled data flows from HTTP headers through the application's processing pipeline and back to the user's browser without adequate sanitization. This flaw aligns with CWE-79, which defines the weakness of Cross-site Scripting, and specifically relates to CWE-74, which addresses injection flaws in web applications.
The operational impact of CVE-2015-6515 extends beyond simple script injection, as it provides attackers with the capability to perform session hijacking, steal sensitive data, and potentially escalate privileges within the Splunk environment. An attacker could leverage this vulnerability to establish persistent access to Splunk Web interfaces, particularly when users with elevated privileges interact with maliciously crafted headers. The implications are particularly severe for organizations relying on Splunk for security monitoring, as compromised Splunk interfaces could provide attackers with access to sensitive log data, system configurations, and monitoring dashboards. The vulnerability also enables attackers to perform phishing attacks against other Splunk users, potentially leading to credential theft and broader compromise of the organization's security infrastructure. This attack vector is particularly concerning given that Splunk is often used for security event monitoring and log analysis, making compromised Splunk interfaces potential gateways for advanced persistent threats.
Organizations affected by this vulnerability should prioritize immediate remediation through official Splunk security patches, specifically upgrading to versions 5.0.13, 6.0.9, 6.1.8, and 6.2.4 or later. The mitigation strategy should include implementing proper header sanitization at the network level through reverse proxies or web application firewalls to filter out potentially malicious header content. Security teams should also conduct comprehensive audits of Splunk configurations to identify any custom applications or dashboards that might be vulnerable to similar header-based injection attacks. Additionally, organizations should implement robust monitoring for suspicious header patterns and establish incident response procedures specifically addressing XSS vulnerabilities in web applications. The vulnerability's presence in Splunk Web aligns with ATT&CK technique T1059.007, which covers Scripting through web application interfaces, and demonstrates the importance of input validation and output encoding in preventing client-side code injection attacks. Organizations should also consider implementing Content Security Policy headers to add an additional layer of protection against XSS attacks, though this mitigation is secondary to the primary patching requirement for addressing the root cause vulnerability.