CVE-2016-4859 in Splunk
Summary
by MITRE
Open redirect vulnerability in Splunk Enterprise 6.4.x prior to 6.4.3, Splunk Enterprise 6.3.x prior to 6.3.6, Splunk Enterprise 6.2.x prior to 6.2.10, Splunk Enterprise 6.1.x prior to 6.1.11, Splunk Enterprise 6.0.x prior to 6.0.12, Splunk Enterprise 5.0.x prior to 5.0.16 and Splunk Light prior to 6.4.3 allows to redirect users to arbitrary web sites and conduct phishing attacks via unspecified vectors.
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Analysis
by VulDB Data Team • 12/23/2020
The CVE-2016-4859 vulnerability represents a critical open redirect flaw affecting multiple versions of Splunk Enterprise and Splunk Light products. This vulnerability falls under the category of CWE-601 Open Redirect, which is classified as a security weakness where applications redirect users to external websites without proper validation of the destination URL. The vulnerability specifically impacts Splunk Enterprise versions 6.4.x prior to 6.4.3, 6.3.x prior to 6.3.6, 6.2.x prior to 6.2.10, 6.1.x prior to 6.1.11, 6.0.x prior to 6.0.12, and 5.0.x prior to 5.0.16, along with Splunk Light prior to 6.4.3. The flaw enables attackers to manipulate the application's redirect functionality to direct users to malicious websites.
The technical implementation of this vulnerability stems from insufficient validation of redirect URLs within Splunk's authentication and navigation mechanisms. When users attempt to access certain Splunk resources, the application processes redirect parameters without adequately verifying whether the target URL belongs to the trusted domain. This allows attackers to craft malicious URLs that appear legitimate but actually redirect users to phishing sites or malicious content. The unspecified vectors mentioned in the description suggest that the vulnerability could be exploited through various entry points including login pages, dashboard navigation, or API endpoints that utilize redirect functionality. The vulnerability creates a pathway for social engineering attacks where users might be tricked into believing they are accessing legitimate Splunk resources while actually being redirected to attacker-controlled domains.
From an operational perspective, this vulnerability poses significant risks to organizations using affected Splunk versions. The open redirect flaw enables sophisticated phishing campaigns where attackers can create convincing fake login pages or malicious sites that appear to be legitimate Splunk interfaces. This capability allows for credential theft, data exfiltration, and potential lateral movement within the network. The impact extends beyond simple phishing as attackers can use the vulnerability to deliver malware, conduct man-in-the-middle attacks, or establish persistent access points. Organizations with Splunk deployments are particularly vulnerable because Splunk often serves as a central monitoring and analytics platform, making it an attractive target for attackers seeking to gain access to sensitive operational data. The vulnerability also affects the trust model of the application, as users may unknowingly navigate to malicious sites while believing they are performing legitimate administrative tasks.
Mitigation strategies for CVE-2016-4859 should focus on immediate patching of affected versions to the recommended secure releases. Organizations must upgrade all affected Splunk Enterprise and Splunk Light installations to versions 6.4.3 or later for their respective major versions. Network administrators should implement URL filtering and monitoring to detect suspicious redirect patterns, while security teams should review and audit existing redirect functionality within the Splunk environment. The implementation of proper input validation and URL sanitization should be enforced to prevent unauthorized redirections. Additionally, organizations should consider implementing web application firewalls to block malicious redirect attempts and conduct regular security assessments to identify similar vulnerabilities in other applications. From an ATT&CK framework perspective, this vulnerability aligns with techniques such as T1566 Phishing and T1071.1001 Application Layer Protocol: Web Protocols, as it enables attackers to exploit web application redirect functionality for malicious purposes. The vulnerability also relates to T1083 File and Directory Discovery and T1046 Network Service Scanning, as attackers may use the redirect capability to gather information about the network environment or target other systems. Security teams should also implement user awareness training to educate personnel about recognizing phishing attempts that may exploit this vulnerability.