CVE-2019-5048 in NitroPDF
Summary
by MITRE
A specifically crafted PDF file can lead to a heap corruption when opened in NitroPDF 12.12.1.522. With careful memory manipulation, this can lead to arbitrary code execution. In order to trigger this vulnerability, the victim would need to open the malicious file.
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Analysis
by VulDB Data Team • 01/07/2024
The vulnerability identified as CVE-2019-5048 represents a critical heap corruption issue affecting NitroPDF version 12.12.1.522, demonstrating a classic buffer overflow condition that can be exploited through maliciously crafted PDF documents. This flaw resides within the PDF parsing and rendering engine of the software, where improper memory management during the processing of specially constructed PDF files creates opportunities for attackers to manipulate heap memory structures. The vulnerability is particularly concerning as it operates at the memory management level, allowing for potential arbitrary code execution when victims open the malicious documents, making it a prime target for social engineering campaigns and targeted attacks.
The technical implementation of this vulnerability stems from inadequate input validation and memory handling within NitroPDF's PDF parser, which fails to properly sanitize or bound-check data structures when processing complex PDF elements. When the application encounters a crafted PDF file containing malformed or oversized data within its internal memory allocation routines, it executes code that corrupts heap memory regions, potentially overwriting critical program structures or return addresses. This heap corruption behavior aligns with CWE-122, which describes improper restriction of operations within the bounds of a memory buffer, and represents a common class of vulnerabilities found in document processing applications that handle untrusted input data. The flaw operates through the standard PDF rendering pipeline where the application attempts to allocate memory for various PDF objects, including graphics, text, and embedded content, without sufficient validation of the input data structure sizes.
The operational impact of CVE-2019-5048 extends beyond simple denial of service or data corruption, as it enables full arbitrary code execution capabilities that can be leveraged for privilege escalation, system compromise, or data exfiltration. Attackers can craft PDF files that, when opened by unsuspecting victims, trigger the heap corruption sequence and subsequently execute malicious payloads within the context of the NitroPDF application. This vulnerability is particularly dangerous in enterprise environments where users frequently open PDF documents from external sources, making it a prime candidate for phishing attacks, supply chain compromises, or targeted campaigns against high-value targets. The attack vector requires user interaction through document opening, which means the vulnerability can be effectively exploited through social engineering techniques, making it particularly difficult to defend against without comprehensive user education and application hardening measures.
Mitigation strategies for this vulnerability should encompass multiple defensive layers including immediate patch deployment from the vendor, application whitelisting of trusted PDF sources, network-based filtering of suspicious PDF content, and user awareness training programs to recognize potentially malicious documents. Organizations should implement the principle of least privilege for PDF viewing applications, ensuring that NitroPDF runs with minimal system privileges and that memory protection mechanisms such as address space layout randomization and data execution prevention are enabled. The vulnerability's exploitation pattern aligns with ATT&CK technique T1204.002, which describes legitimate user execution through social engineering, emphasizing the need for comprehensive endpoint protection solutions that can detect and block malicious PDF file execution. Additionally, regular security assessments of document processing applications and implementation of sandboxing mechanisms can significantly reduce the attack surface and prevent exploitation of similar heap corruption vulnerabilities in the future.