CVE-2017-9408 in Poppler
Summary
by MITRE
In Poppler 0.54.0, a memory leak vulnerability was found in the function Object::initArray in Object.cc, which allows attackers to cause a denial of service via a crafted file.
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Analysis
by VulDB Data Team • 05/25/2020
The memory leak vulnerability identified as CVE-2017-9408 resides within the Poppler PDF rendering library version 0.54.0, specifically within the Object::initArray function located in the Object.cc source file. This flaw represents a critical security issue that manifests when the library processes maliciously crafted PDF documents, creating a condition where allocated memory is not properly released during the object initialization process. The vulnerability is categorized under CWE-401 as a failure to release memory resources, which directly impacts the library's memory management integrity. Poppler, being a widely-used PDF rendering engine employed by numerous applications including web browsers, desktop viewers, and document processing systems, makes this vulnerability particularly concerning for system administrators and security professionals.
The technical exploitation of this memory leak occurs when an attacker constructs a specially formatted PDF file that triggers the Object::initArray function with malformed array data structures. During the initialization process, the function fails to properly handle memory allocation for array objects, leading to memory fragments that remain allocated even after the object initialization should complete. This improper memory management creates a gradual accumulation of unreleased memory blocks that progressively consume system resources. The vulnerability is particularly dangerous because it can be triggered through normal PDF file processing operations, meaning that any application relying on Poppler for PDF handling could be vulnerable to denial of service attacks. The memory leak compounds over time, potentially leading to complete system resource exhaustion and application crashes, as the operating system's memory management becomes increasingly fragmented and constrained.
The operational impact of CVE-2017-9408 extends far beyond simple resource consumption, as it creates a vector for persistent denial of service attacks that can affect any system processing PDF documents through vulnerable Poppler implementations. Applications that incorporate Poppler for PDF rendering, including web browsers like Firefox and Chrome when using Poppler as a backend, desktop PDF viewers, document conversion tools, and server-side applications handling PDF uploads, all represent potential attack surfaces. The vulnerability aligns with ATT&CK technique T1499.004 for resource exhaustion, where adversaries leverage memory leaks to degrade system performance. In enterprise environments, this vulnerability could enable attackers to disrupt document processing workflows, cause application instability, or even facilitate more sophisticated attacks by exhausting system resources and creating opportunities for additional exploits. The vulnerability is particularly dangerous in automated environments where PDF processing occurs continuously, as the memory leak can accumulate unnoticed until system performance degrades significantly.
Mitigation strategies for CVE-2017-9408 should prioritize immediate patching of affected Poppler installations to version 0.56.0 or later, where the memory leak has been corrected through proper memory management in the Object::initArray function. System administrators should conduct comprehensive vulnerability assessments to identify all applications and services utilizing vulnerable Poppler versions, implementing monitoring solutions to detect anomalous memory usage patterns that might indicate exploitation attempts. Network segmentation and application whitelisting can help limit the potential impact by restricting access to PDF processing capabilities. Additionally, implementing sandboxing mechanisms for PDF processing and deploying intrusion detection systems that monitor for PDF file processing anomalies can provide layered defense against exploitation attempts. The vulnerability serves as a reminder of the importance of regular security updates and proper memory management practices in open source libraries, particularly those handling untrusted input data. Organizations should also consider implementing automated patch management processes and vulnerability scanning tools to proactively identify and remediate similar memory-related issues in their software dependencies.