CVE-2019-5042 in Aspose.PDF
Summary
by MITRE
An exploitable Use-After-Free vulnerability exists in the way FunctionType 0 PDF elements are processed in Aspose.PDF 19.2 for C++. A specially crafted PDF can cause a dangling heap pointer, resulting in a use-after-free. An attacker can send a malicious PDF to trigger this vulnerability.
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Analysis
by VulDB Data Team • 12/26/2023
The vulnerability CVE-2019-5042 represents a critical use-after-free flaw in Aspose.PDF 19.2 for C++ that specifically targets the processing of FunctionType 0 PDF elements. This type of vulnerability occurs when a program continues to reference memory locations after they have been freed, creating opportunities for malicious exploitation. The issue manifests during the parsing of PDF documents where FunctionType 0 elements are handled, which are typically used for defining mathematical functions in PDF content streams. The flaw allows attackers to craft malicious PDF files that, when processed by the vulnerable library, can trigger memory corruption.
The technical implementation of this vulnerability involves improper memory management within the PDF parsing engine of Aspose.PDF. When FunctionType 0 elements are encountered in a PDF document, the library allocates memory for these elements and subsequently frees it during the processing cycle. However, the code fails to properly invalidate references to this freed memory, creating dangling pointers that can be exploited. The use-after-free condition occurs because the application continues to access the memory location even after it has been deallocated, potentially allowing an attacker to manipulate the freed memory region before it gets overwritten.
From an operational standpoint, this vulnerability poses significant risks to organizations that rely on Aspose.PDF for document processing, particularly in environments where PDF files are received from untrusted sources. The exploitation scenario involves an attacker crafting a malicious PDF file containing specially constructed FunctionType 0 elements that, when opened or processed by applications using the vulnerable library, trigger the use-after-free condition. This can lead to arbitrary code execution, application crashes, or potential information disclosure, depending on the specific implementation details and the target system's memory layout. The vulnerability is particularly dangerous in server environments where PDF processing is automated or in applications that handle user-uploaded documents without proper validation.
The impact of this vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software implementations. This weakness is classified as a memory safety issue that can be exploited through various attack vectors including heap spraying techniques and controlled memory manipulation. The ATT&CK framework categorizes this as a memory corruption vulnerability that can be leveraged for privilege escalation or code execution in the target environment. Organizations should prioritize immediate patching of this vulnerability through the vendor's official updates, as the use-after-free nature makes it particularly attractive to threat actors seeking persistent access to affected systems. Additionally, implementing proper input validation and sandboxing mechanisms for PDF processing can help mitigate the risk while waiting for official security patches to be deployed across affected environments.