CVE-2018-20593 in Mini-XML
Summary
by MITRE
In Mini-XML (aka mxml) v2.12, there is stack-based buffer overflow in the scan_file function in mxmldoc.c.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 06/22/2023
The vulnerability CVE-2018-20593 represents a critical stack-based buffer overflow in the Mini-XML library version 2.12, specifically within the scan_file function located in the mxmldoc.c source file. This flaw exists in the documentation generation component of the library, which is commonly used for processing XML files in embedded systems and applications requiring lightweight XML parsing capabilities. The issue arises when the library processes malformed or specially crafted XML input during the documentation generation phase, creating a dangerous condition that can be exploited by attackers to execute arbitrary code.
The technical root cause of this vulnerability stems from inadequate bounds checking within the scan_file function, which processes XML documents to generate documentation output. When the function encounters certain input patterns, it fails to properly validate the size of data being copied to stack-allocated buffers, leading to a classic stack overflow condition. This vulnerability is categorized under CWE-121 Stack-based Buffer Overflow, which occurs when data is copied into a buffer on the stack without proper size validation, allowing the overflow to overwrite adjacent stack memory including return addresses and function parameters. The flaw demonstrates poor input validation practices that violate fundamental security principles for memory safety.
The operational impact of CVE-2018-20593 extends beyond simple code execution, as it can be leveraged to achieve remote code execution in applications that utilize Mini-XML for processing untrusted XML input. Attackers can craft malicious XML documents that trigger the buffer overflow when the library processes them during documentation generation, potentially allowing arbitrary code execution with the privileges of the affected application. This vulnerability particularly affects embedded systems, IoT devices, and applications that rely on Mini-XML for XML processing, as these environments often have limited security controls and may process XML content from untrusted sources. The vulnerability is also relevant to applications using the library for XML validation or parsing tasks, as the same overflow condition could be triggered during normal XML processing operations.
Mitigation strategies for this vulnerability include immediate patching of the Mini-XML library to version 2.13 or later, which contains the necessary fixes for the buffer overflow condition. System administrators should also implement input validation measures to filter or sanitize XML content before processing, particularly when dealing with untrusted input sources. The vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: Python, as the overflow can be exploited to execute malicious code, and T1203 for Exploitation for Client Execution, since the vulnerability affects client-side applications that process XML files. Organizations should also consider implementing runtime protections such as stack canaries, address space layout randomization, and non-executable stack protections to reduce the exploitability of such buffer overflow conditions. Additionally, security monitoring should be enhanced to detect anomalous XML processing patterns that could indicate exploitation attempts.