CVE-2015-5531 in Elasticsearch
Summary
by MITRE
Directory traversal vulnerability in Elasticsearch before 1.6.1 allows remote attackers to read arbitrary files via unspecified vectors related to snapshot API calls.
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Analysis
by VulDB Data Team • 11/29/2024
The vulnerability identified as CVE-2015-5531 represents a critical directory traversal flaw within Elasticsearch versions prior to 1.6.1, specifically impacting the snapshot API functionality. This vulnerability enables remote attackers to access arbitrary files on the system by exploiting unspecified vectors related to how the snapshot API processes file paths and references. The issue stems from inadequate input validation and path sanitization mechanisms within the Elasticsearch snapshot implementation, allowing malicious actors to craft requests that traverse directory structures beyond intended boundaries.
The technical exploitation of this vulnerability occurs through the snapshot API which is designed to create and manage backups of Elasticsearch indices. Attackers can manipulate API requests to include directory traversal sequences such as ../ or ..\ that bypass normal file access controls. This flaw falls under CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The vulnerability allows unauthorized access to sensitive system files, configuration data, and potentially user information stored on the same system hosting the Elasticsearch instance.
From an operational impact perspective, this vulnerability poses significant risks to organizations utilizing Elasticsearch for data storage and retrieval. Remote attackers can exploit this weakness to access critical system files, including but not limited to configuration files that may contain database credentials, encryption keys, or other sensitive authentication information. The potential for data exfiltration increases substantially as attackers can navigate through the file system to locate and retrieve valuable information. Additionally, this vulnerability can serve as a stepping stone for further attacks within the network infrastructure, as compromised Elasticsearch instances often contain data that may be used to escalate privileges or move laterally across systems.
The attack surface for this vulnerability extends beyond simple file reading capabilities, as it can be combined with other exploitation techniques to achieve more severe outcomes. According to ATT&CK framework, this vulnerability aligns with techniques such as T1083 (File and Directory Discovery) and T1566 (Phishing with Malicious Attachment), as attackers can use the directory traversal to discover system files and potentially deliver additional malicious payloads. Organizations running vulnerable Elasticsearch versions face the risk of complete system compromise, particularly when the Elasticsearch service runs with elevated privileges or when sensitive data is stored within the same file system hierarchy. The vulnerability also impacts compliance requirements, as unauthorized access to system files may violate data protection regulations and industry standards such as GDPR, HIPAA, or PCI DSS.
Mitigation strategies for CVE-2015-5531 primarily involve upgrading to Elasticsearch version 1.6.1 or later, which includes proper input validation and path sanitization measures. Organizations should also implement network segmentation to limit access to Elasticsearch instances, particularly restricting direct internet exposure. Additional protective measures include configuring proper access controls, implementing monitoring for unusual API activity, and conducting regular security assessments of Elasticsearch deployments. The vulnerability demonstrates the importance of maintaining up-to-date software versions and implementing robust input validation practices across all system components to prevent similar directory traversal attacks from compromising system integrity.