CVE-2017-5662 in Utilities Network Management System
Summary
by MITRE
In Apache Batik before 1.9, files lying on the filesystem of the server which uses batik can be revealed to arbitrary users who send maliciously formed SVG files. The file types that can be shown depend on the user context in which the exploitable application is running. If the user is root a full compromise of the server - including confidential or sensitive files - would be possible. XXE can also be used to attack the availability of the server via denial of service as the references within a xml document can trivially trigger an amplification attack.
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Analysis
by VulDB Data Team • 04/18/2023
Apache Batik version 1.9 and earlier contains a critical information disclosure vulnerability that allows remote attackers to access arbitrary files on the server filesystem through maliciously crafted SVG files. This vulnerability stems from insufficient input validation and improper handling of external entity references within the SVG processing pipeline. The flaw exists because Batik fails to adequately sanitize file paths and external entity declarations when parsing SVG documents, creating an attack surface where malicious actors can exploit XML external entity (XXE) processing to traverse the filesystem and retrieve sensitive data. The vulnerability is particularly dangerous because it can be exploited by any user who can submit SVG content to a vulnerable application, making it a significant risk for web applications that process user-uploaded SVG files.
The technical implementation of this vulnerability leverages XML external entity processing mechanisms that are inherently present in the Batik library's SVG parser. When an SVG file contains malicious external entity declarations or file references, the parser attempts to resolve these references against the local filesystem rather than properly validating or restricting access to system resources. This behavior creates a direct path for attackers to access files that should normally be protected, depending on the privileges of the process running the Batik application. The severity escalates significantly when the vulnerable application runs with elevated privileges such as root access, as attackers can then access system configuration files, user credentials, database connection details, and other sensitive information that would normally be restricted. The vulnerability is classified under CWE-20, which addresses improper input validation, and aligns with ATT&CK technique T1059.007 for XML External Entity Processing.
The operational impact of this vulnerability extends beyond simple information disclosure to include potential system compromise and availability disruption. Attackers can leverage the XXE functionality not only to read arbitrary files but also to perform denial of service attacks through resource exhaustion. The amplification effect occurs when malicious XML references trigger multiple file access operations or recursive entity expansions that consume significant server resources. This dual nature makes the vulnerability particularly dangerous in production environments where the application may be processing untrusted SVG content from multiple users. The vulnerability affects any system that processes SVG files using the affected Batik versions, including web applications, content management systems, and document processing services that utilize the library for SVG rendering or conversion.
Mitigation strategies for this vulnerability require immediate patching of the Batik library to version 1.9 or later, where the XXE processing has been properly addressed. Organizations should implement strict input validation for all SVG content, particularly when processing user-uploaded files, and disable external entity processing entirely within the Batik configuration. Network-level controls such as firewalls and web application firewalls can help limit access to SVG processing endpoints, while monitoring systems should be deployed to detect unusual file access patterns or resource consumption spikes that might indicate exploitation attempts. Additionally, system administrators should ensure that applications using Batik run with the minimum required privileges to limit the potential damage from successful exploitation attempts. The vulnerability highlights the importance of proper XML security configuration and demonstrates why external entity processing should be disabled in applications that do not explicitly require it for functionality.