CVE-2015-5377 in Elasticsearch
Summary
by MITRE
** DISPUTED ** Elasticsearch before 1.6.1 allows remote attackers to execute arbitrary code via unspecified vectors involving the transport protocol. NOTE: ZDI appears to claim that CVE-2015-3253 and CVE-2015-5377 are the same vulnerability.
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Analysis
by VulDB Data Team • 11/23/2024
The vulnerability identified as CVE-2015-5377 represents a critical remote code execution flaw in Elasticsearch versions prior to 1.6.1, specifically within the transport protocol implementation. This vulnerability exists in the way Elasticsearch handles incoming network connections and data processing through its transport layer, which is designed to facilitate communication between Elasticsearch nodes in a cluster. The transport protocol operates on TCP port 9300 by default and is responsible for node discovery, cluster coordination, and data replication across distributed Elasticsearch instances. Attackers exploiting this vulnerability could potentially execute arbitrary code on affected systems, making it a severe threat to Elasticsearch deployments in production environments.
The technical nature of this vulnerability stems from insufficient input validation and sanitization within the transport protocol handler. When Elasticsearch receives network traffic through its transport layer, it processes incoming data packets containing serialized objects and commands that are typically used for node communication and cluster management. The flaw occurs during the deserialization process where untrusted data is interpreted without proper security checks, allowing malicious actors to craft specially crafted packets that trigger unintended code execution. This type of vulnerability falls under the CWE-502 category of "Deserialization of Untrusted Data," which is a well-documented weakness in software systems that handle serialized object data from external sources. The vulnerability's impact is amplified because the transport protocol is designed to be accessible to other nodes in a cluster, meaning attackers could potentially exploit it from external networks without requiring authentication.
The operational impact of CVE-2015-5377 extends beyond simple remote code execution, as it can enable attackers to gain complete control over affected Elasticsearch instances and potentially compromise entire cluster deployments. An attacker who successfully exploits this vulnerability could access sensitive data stored in Elasticsearch, modify or delete information, install backdoors, or use the compromised node as a pivot point to attack other systems within the network. The distributed nature of Elasticsearch clusters means that a single compromised node could provide attackers with access to data across multiple systems. This vulnerability particularly affects organizations that expose their Elasticsearch instances to untrusted networks or have poorly configured firewall rules, as the transport protocol typically operates on a dedicated port that may not be properly protected. The ATT&CK framework categorizes this type of vulnerability under T1059.007 for "Command and Scripting Interpreter: PowerShell" and T1068 for "Exploitation for Privilege Escalation," highlighting the potential for attackers to leverage such vulnerabilities for broader system compromise.
Organizations should prioritize immediate remediation of CVE-2015-5377 by upgrading to Elasticsearch version 1.6.1 or later, which includes patches addressing the transport protocol deserialization issues. Network segmentation and firewall configuration should be implemented to restrict access to the transport protocol port 9300, limiting exposure to trusted networks only. Additional mitigations include implementing network intrusion detection systems to monitor for suspicious traffic patterns on the transport port, enabling authentication and encryption for cluster communications, and regularly reviewing and updating Elasticsearch configurations to follow security best practices. The vulnerability also underscores the importance of following the principle of least privilege in distributed systems, ensuring that only necessary components have access to cluster communication ports. Organizations should also consider implementing application-level firewalls or reverse proxies to add an additional layer of protection for Elasticsearch transport communications. Given that this vulnerability was reportedly disputed by ZDI and may overlap with CVE-2015-3253, security teams should verify their systems against both CVE identifiers and ensure comprehensive patch management across all Elasticsearch installations.