CVE-2016-9177 in Spark
Summary
by MITRE
Directory traversal vulnerability in Spark 2.5 allows remote attackers to read arbitrary files via a .. (dot dot) in the URI.
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Analysis
by VulDB Data Team • 09/29/2022
The CVE-2016-9177 vulnerability represents a critical directory traversal flaw within Apache Spark 2.5 that exposes systems to unauthorized file access. This vulnerability specifically affects the web interface component of Spark, where improper input validation allows malicious actors to manipulate URI paths through the use of .. (dot dot) sequences. The flaw exists in the way Spark processes file paths when serving web content, creating an opportunity for remote attackers to navigate beyond the intended directory boundaries and access arbitrary files on the underlying file system.
The technical implementation of this vulnerability stems from insufficient sanitization of user-supplied URI parameters within Spark's web server component. When a user submits a request containing directory traversal sequences, the application fails to properly validate or normalize the path before processing, allowing the attacker to craft malicious requests that can traverse directories and access files outside the intended scope. This type of vulnerability falls under the CWE-22 category for Improper Limitation of a Pathname to a Restricted Directory, which is a well-established weakness in software security design. The vulnerability enables attackers to potentially access sensitive configuration files, log files, or even system files that should remain protected from unauthorized access.
The operational impact of this vulnerability extends beyond simple file disclosure, as it can provide attackers with access to potentially sensitive data stored within the Spark environment. In a typical Spark deployment, this could expose cluster configurations, user credentials, or other confidential information that might be stored in accessible locations. The remote nature of the attack means that an attacker does not require local system access or authentication to exploit the vulnerability, making it particularly dangerous in environments where Spark is exposed to untrusted networks. This vulnerability aligns with ATT&CK technique T1083 (File and Directory Discovery) and T1566 (Phishing with Malicious Attachments) as attackers can use this weakness to gather intelligence about the system and potentially escalate privileges.
Organizations running affected versions of Spark should implement immediate mitigations including upgrading to patched versions of the software, implementing proper input validation at the web server level, and restricting access to Spark web interfaces through network segmentation and authentication mechanisms. The vulnerability demonstrates the importance of proper path validation and the principle of least privilege in web application security. Additionally, implementing web application firewalls and monitoring for suspicious URI patterns can help detect and prevent exploitation attempts. Security teams should also conduct thorough audits of their Spark deployments to ensure that no other components are vulnerable to similar directory traversal attacks. The incident highlights the necessity of comprehensive security testing including penetration testing and code reviews to identify such path traversal vulnerabilities before they can be exploited by malicious actors.