CVE-2016-4857 in Splunk
Summary
by MITRE
Open redirect vulnerability in Splunk Enterprise 6.4.x prior to 6.4.2, Splunk Enterprise 6.3.x prior to 6.3.6, Splunk Enterprise 6.2.x prior to 6.2.11 and Splunk Light prior to 6.4.2 allows to redirect users to arbitrary web sites and conduct phishing attacks via unspecified vectors.
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Analysis
by VulDB Data Team • 09/25/2020
The CVE-2016-4857 vulnerability represents a critical open redirect flaw in Splunk Enterprise and Splunk Light products that significantly impacts web application security. This vulnerability exists in multiple versions of Splunk Enterprise including 6.4.x prior to 6.4.2, 6.3.x prior to 6.3.6, and 6.2.x prior to 6.2.11, as well as Splunk Light prior to 6.4.2. The flaw allows malicious actors to manipulate web redirects within the Splunk interface, potentially routing users to attacker-controlled domains without proper validation. This vulnerability falls under the CWE-601 Open Redirect weakness category, which is classified as a security misconfiguration that enables attackers to redirect users to malicious websites. The vulnerability's classification aligns with ATT&CK technique T1566.001, which covers phishing through spearphishing attachments, as the open redirect can be leveraged to deliver phishing attacks by redirecting users to malicious sites that appear legitimate. The unspecified vectors in the vulnerability description suggest that the flaw could be exploited through various input parameters within Splunk's web interface, potentially including URL parameters, authentication redirects, or navigation elements.
The technical implementation of this vulnerability stems from insufficient validation of redirect URLs within Splunk's web application framework. When users interact with Splunk's web interface, particularly during authentication flows or navigation operations, the application fails to properly validate or sanitize the target URLs for redirects. This allows an attacker to craft malicious URLs that contain encoded redirect parameters pointing to external domains. The vulnerability's impact is particularly severe because Splunk is commonly used for security monitoring and log analysis, making it a prime target for attackers seeking to compromise security operations. Attackers can exploit this vulnerability by crafting phishing emails or malicious links that, when clicked by unsuspecting users, redirect them to attacker-controlled domains designed to harvest credentials or deploy malware. The open redirect mechanism can be particularly dangerous in enterprise environments where Splunk administrators and security analysts frequently access the platform, as these users are often targets for sophisticated social engineering attacks.
The operational impact of CVE-2016-4857 extends beyond simple phishing attacks, creating broader security risks within Splunk environments. Organizations using affected Splunk versions face increased risk of credential theft, malware distribution, and advanced persistent threat campaigns. The vulnerability can be exploited in conjunction with other attack vectors, such as cross-site scripting or credential brute force attacks, to create more sophisticated attack chains. Security teams that rely on Splunk for monitoring and alerting may find their systems compromised through this vulnerability, potentially leading to undetected breaches or compromised security analytics. The vulnerability's exploitation can result in unauthorized access to sensitive security data, disruption of security monitoring capabilities, and potential lateral movement within network environments. Additionally, the presence of this vulnerability can undermine user trust in the Splunk platform and may require immediate patching across all affected systems, creating operational disruption during the remediation process.
Organizations should prioritize immediate remediation of CVE-2016-4857 by upgrading to patched versions of Splunk Enterprise and Splunk Light, specifically versions 6.4.2, 6.3.6, and 6.2.11 respectively. The patch addresses the core validation flaw in redirect handling by implementing proper URL sanitization and validation mechanisms that prevent external domain redirects. Network administrators should also consider implementing additional security controls such as web application firewalls, URL filtering, and monitoring for suspicious redirect patterns within Splunk logs. Security teams should conduct comprehensive vulnerability assessments to identify any potential exploitation attempts and monitor for unusual redirect behavior in Splunk's web access logs. Organizations should also review their Splunk configurations to ensure that unnecessary redirect functionality is disabled and that proper access controls are in place to limit exposure to this vulnerability. The mitigation strategy should include user education about phishing risks and the importance of verifying URLs before clicking on links, particularly in security-sensitive environments where Splunk is used for critical monitoring functions.