CVE-2015-4152 in Logstash
Summary
by MITRE
Directory traversal vulnerability in the file output plugin in Elasticsearch Logstash before 1.4.3 allows remote attackers to write to arbitrary files via vectors related to dynamic field references in the path option.
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Analysis
by VulDB Data Team • 05/21/2022
The directory traversal vulnerability identified as CVE-2015-4152 affects Elasticsearch Logstash versions prior to 1.4.3, representing a critical security flaw in the file output plugin component. This vulnerability stems from insufficient validation of dynamic field references within the path option, creating an avenue for remote attackers to manipulate file system operations. The flaw enables adversaries to write data to arbitrary locations on the system, potentially compromising the integrity and confidentiality of sensitive information stored within the log processing environment. The vulnerability exists because the system fails to properly sanitize user-supplied input that gets processed through dynamic field references, allowing malicious actors to craft payloads that bypass normal file access controls.
The technical implementation of this vulnerability occurs within the file output plugin where dynamic field references are processed without adequate validation mechanisms. When Logstash processes configuration files containing dynamic path references, the system does not properly validate whether the specified paths fall within the intended directory boundaries. Attackers can exploit this by crafting malicious configurations that include directory traversal sequences such as ../ or ..\ in the path option, which then get interpreted by the file system without proper sanitization. This weakness directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. The vulnerability demonstrates a classic case of insufficient input validation where user-controllable data is directly used in file system operations without proper escaping or normalization.
The operational impact of CVE-2015-4152 extends beyond simple unauthorized file access, potentially enabling complete system compromise through various attack vectors. Remote attackers can leverage this vulnerability to overwrite critical system files, inject malicious code into log processing workflows, or establish persistence mechanisms by creating backdoor files in strategic locations. The vulnerability particularly affects environments where Logstash is configured with dynamic output paths that incorporate user input or external data sources, making it especially dangerous in multi-tenant or shared hosting scenarios. Organizations using vulnerable versions of Logstash face significant risk of data breaches, system corruption, and potential lateral movement within their network infrastructure. The attack surface is further expanded when considering that Logstash often processes sensitive log data from various sources, making the compromise of file output functionality potentially devastating for security monitoring and incident response capabilities.
Mitigation strategies for CVE-2015-4152 primarily focus on immediate version upgrades to Logstash 1.4.3 or later, which includes proper input validation and sanitization for dynamic field references. Organizations should implement strict configuration management policies that prevent the use of dynamic path references with untrusted input sources, and establish comprehensive monitoring for suspicious file system activities. Security teams should conduct thorough audits of all Logstash configurations to identify and remediate instances where dynamic path options might be vulnerable to manipulation. Additionally, network segmentation and access controls should be implemented to limit the potential impact of successful exploitation, while regular security assessments should verify that no other components within the log processing pipeline contain similar vulnerabilities. The ATT&CK framework categorizes this vulnerability under T1059 Command and Scripting Interpreter and T1078 Valid Accounts, as exploitation typically involves leveraging legitimate system access to manipulate file system operations and potentially establish persistent access through crafted file writes.