CVE-2019-10873 in Poppler
Summary
by MITRE
An issue was discovered in Poppler 0.74.0. There is a NULL pointer dereference in the function SplashClip::clipAALine at splash/SplashClip.cc.
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Analysis
by VulDB Data Team • 08/27/2023
The vulnerability identified as CVE-2019-10873 represents a critical NULL pointer dereference flaw within the Poppler PDF rendering library version 0.74.0. This issue manifests specifically within the SplashClip::clipAALine function located in the splash/SplashClip.cc source file, where the software fails to properly validate pointer references before attempting to access memory locations. The vulnerability arises from insufficient input validation and error handling mechanisms that allow maliciously crafted PDF documents to trigger unexpected program behavior. Attackers can exploit this weakness by constructing specially formatted PDF files that, when processed by vulnerable Poppler implementations, cause the application to attempt dereferencing a null pointer during anti-aliased line clipping operations. This particular flaw falls under the CWE-476 category of NULL Pointer Dereference, which is a well-documented vulnerability pattern that has been consistently identified as a high-risk issue in software security assessments.
The technical exploitation of this vulnerability occurs when a PDF document contains malformed graphics data that triggers the SplashClip::clipAALine function with uninitialized or invalid pointer values. During the execution of anti-aliased line clipping operations, the software attempts to access memory through a null pointer reference, resulting in an application crash or potential memory corruption. This type of vulnerability can lead to denial of service conditions where legitimate users cannot process PDF documents, or in more severe cases, could potentially be leveraged for remote code execution depending on the broader context of the application using Poppler. The vulnerability demonstrates characteristics consistent with the ATT&CK technique T1203, where adversaries may leverage application flaws to cause system instability or crash services, though the specific exploitation vector would require additional attack surface considerations.
The operational impact of CVE-2019-10873 extends beyond simple application crashes to potentially compromise the availability and stability of systems that rely on Poppler for PDF processing. This includes web applications, document management systems, and any software platforms that utilize Poppler as a PDF rendering engine for converting or displaying PDF content. The vulnerability affects not only desktop applications but also server-side implementations that process untrusted PDF files from users or external sources, creating a significant risk for organizations operating web services or document processing pipelines. Organizations using vulnerable versions of Poppler may experience unexpected service interruptions, user experience degradation, and potential security exposure if attackers can craft payloads that exploit this flaw to cause system instability or gain unauthorized access to system resources. The vulnerability's impact is particularly concerning in environments where PDF processing is automated or occurs without proper input sanitization, as the exploitation can be fully automated and does not require user interaction beyond viewing the malicious document.
Mitigation strategies for CVE-2019-10873 primarily focus on immediate software updates to versions that contain the patched implementation of the SplashClip::clipAALine function. System administrators should prioritize upgrading Poppler to versions 0.75.0 or later, where the NULL pointer dereference has been addressed through proper pointer validation and initialization checks. Additionally, implementing input validation measures at the application level can provide defense-in-depth protection, including sanitizing PDF inputs, implementing proper error handling for rendering operations, and monitoring for unusual memory access patterns that may indicate exploitation attempts. Organizations should also consider deploying network-based intrusion detection systems that can identify malicious PDF content patterns and implementing sandboxing techniques to isolate PDF processing operations from critical system components. The fix typically involves adding null pointer checks before accessing pointer variables within the clipping function and ensuring proper initialization of all memory references during anti-aliased line processing operations, which aligns with standard secure coding practices recommended by both CWE guidelines and industry security frameworks.