CVE-2017-7511 in Poppler
Summary
by MITRE
poppler since version 0.17.3 has been vulnerable to NULL pointer dereference in pdfunite triggered by specially crafted documents.
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Analysis
by VulDB Data Team • 12/07/2022
The vulnerability identified as CVE-2017-7511 represents a critical NULL pointer dereference flaw within the poppler PDF library version 0.17.3 and later. This issue specifically affects the pdfunite utility, which is part of the poppler suite designed for manipulating and converting PDF documents. The flaw arises from insufficient input validation and error handling within the pdfunite component, creating a scenario where maliciously crafted PDF files can trigger a segmentation fault when processed by the utility.
The technical implementation of this vulnerability stems from the pdfunite utility's failure to properly validate and sanitize input PDF documents before processing them. When encountering specially crafted PDF files containing malformed or unexpected data structures, the utility attempts to dereference a NULL pointer, leading to a crash that can potentially be exploited for denial-of-service attacks or, in more sophisticated scenarios, arbitrary code execution. This type of vulnerability falls under the Common Weakness Enumeration category CWE-476, which specifically addresses NULL pointer dereference conditions that can lead to application instability and potential security breaches.
The operational impact of CVE-2017-7511 extends beyond simple service disruption, as it can be leveraged in various attack vectors within the ATT&CK framework. The vulnerability particularly affects systems that rely on poppler for PDF processing, including web applications, document management systems, and automated PDF handling services. Attackers can exploit this flaw by uploading malicious PDF files to systems that utilize pdfunite for document manipulation, potentially causing system crashes, service unavailability, and resource exhaustion. The vulnerability is especially concerning in environments where automated PDF processing occurs, such as email servers, content management systems, and web applications that accept PDF uploads.
Mitigation strategies for this vulnerability should focus on immediate patching of affected poppler versions, with all systems running pdfunite or other poppler utilities requiring updates to versions that address the NULL pointer dereference issue. Organizations should implement input validation and sanitization measures for all PDF processing workflows, including the deployment of PDF analysis tools that can detect and quarantine suspicious documents before they reach the pdfunite utility. Additionally, system administrators should consider implementing sandboxing techniques and privilege separation when processing PDF documents, as recommended in the ATT&CK framework for preventing successful exploitation of similar vulnerabilities. The vulnerability also underscores the importance of regular security assessments and maintaining up-to-date software libraries to prevent exploitation of known weaknesses in document processing utilities.