CVE-2021-38568 in PhantomPDF
Summary
by MITRE • 08/12/2021
An issue was discovered in Foxit Reader and PhantomPDF before 10.1.4. It allows memory corruption during conversion of a PDF document to a different document format.
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Analysis
by VulDB Data Team • 08/16/2021
The vulnerability identified as CVE-2021-38568 represents a critical memory corruption flaw affecting Foxit Reader and PhantomPDF software versions prior to 10.1.4. This issue manifests during the document conversion process when PDF files are transformed into alternative formats, creating a pathway for potential exploitation that could compromise system integrity and user data confidentiality. The flaw exists within the software's handling of PDF document parsing and transformation logic, specifically when processing certain malformed or crafted input files that trigger unexpected memory behavior.
Technical analysis reveals that this vulnerability stems from inadequate input validation and memory management practices within the PDF conversion engine. When the software encounters specific PDF structures or malformed elements during format conversion, the application fails to properly allocate or manage memory resources, resulting in buffer overflows or memory corruption conditions. This type of vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which addresses buffer overflow vulnerabilities in heap-based memory structures. The flaw demonstrates characteristics of memory safety issues that commonly provide attackers with opportunities to execute arbitrary code or cause denial of service conditions.
The operational impact of CVE-2021-38568 extends beyond simple application instability, as it creates potential attack vectors for malicious actors seeking to compromise systems through targeted exploitation. Attackers could craft malicious PDF documents designed to trigger the memory corruption during conversion, potentially leading to remote code execution on vulnerable systems. This vulnerability particularly affects environments where users frequently process PDF documents from untrusted sources, such as email attachments or web downloads, making it a significant concern for enterprise security. The attack surface is further expanded by the widespread use of Foxit Reader and PhantomPDF in both corporate and government sectors, where sensitive document handling occurs regularly.
Mitigation strategies for this vulnerability require immediate patch management to upgrade affected software to version 10.1.4 or later, which contains the necessary fixes for the memory corruption issue. Organizations should implement strict document validation policies, including sandboxing PDF processing operations and employing automated scanning tools to detect potentially malicious PDF files before conversion. Security teams should also consider network-level controls such as web application firewalls and content filtering systems to prevent the delivery of suspicious PDF content to end-user systems. The vulnerability demonstrates the importance of maintaining up-to-date software versions and implementing defense-in-depth strategies, as outlined in the mitre attack framework where such memory corruption vulnerabilities often map to techniques involving code injection and privilege escalation. Additionally, regular security assessments and penetration testing should be conducted to identify similar weaknesses in document processing pipelines and other software components that handle untrusted input data.