CVE-2019-9543 in Poppler
Summary
by MITRE
An issue was discovered in Poppler 0.74.0. A recursive function call, in JBIG2Stream::readGenericBitmap() located in JBIG2Stream.cc, can be triggered by sending a crafted pdf file to (for example) the pdfseparate binary. It allows an attacker to cause Denial of Service (Segmentation fault) or possibly have unspecified other impact. This is related to JArithmeticDecoder::decodeBit.
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Analysis
by VulDB Data Team • 07/26/2023
The vulnerability identified as CVE-2019-9543 represents a critical security flaw within the Poppler PDF rendering library version 0.74.0, specifically affecting the JBIG2 image decoding functionality. This issue manifests through a recursive function call pattern that occurs within the JBIG2Stream::readGenericBitmap() method, which is implemented in the JBIG2Stream.cc source file. The vulnerability is particularly concerning because it can be triggered through the manipulation of specially crafted pdf files, making it exploitable in real-world scenarios where users process untrusted PDF documents. The attack vector is particularly dangerous as it can be executed against common Poppler utilities such as the pdfseparate binary, which is frequently used for splitting PDF files into individual pages.
The technical root cause of this vulnerability stems from inadequate input validation within the JBIG2 arithmetic decoding process, specifically within the JArithmeticDecoder::decodeBit function that serves as a foundational component for JBIG2 image decompression. When a maliciously crafted PDF file is processed, the recursive call pattern in JBIG2Stream::readGenericBitmap() can lead to excessive stack consumption, ultimately resulting in a segmentation fault that crashes the application. This recursive behavior creates an exploitable condition where an attacker can craft a PDF document that, when processed by Poppler, triggers an infinite recursion or stack overflow scenario. The vulnerability is categorized under CWE-674, which deals with Uncontrolled Recursion, and represents a classic example of how improper handling of recursive algorithms can lead to denial of service conditions in security-critical software components.
The operational impact of CVE-2019-9543 extends beyond simple denial of service, as the vulnerability can potentially lead to more severe consequences depending on the execution environment and how the affected software is utilized. In web applications or services that process PDF documents from untrusted sources, this vulnerability could allow attackers to disrupt service availability, leading to significant operational downtime and potential financial losses. The attack is particularly dangerous in automated processing environments where PDF files are automatically handled without user intervention, as the vulnerability could be exploited to cause cascading failures across multiple systems. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers network denial of service attacks, and T1059.007, representing script-based command execution through vulnerable software components. The vulnerability affects a wide range of systems that rely on Poppler for PDF processing, including web browsers, document management systems, and security scanning tools.
Mitigation strategies for CVE-2019-9543 should focus on immediate patching of affected Poppler versions, as the vulnerability was resolved in subsequent releases through proper input validation and recursion depth limiting mechanisms. Organizations should implement comprehensive input validation for PDF files, particularly those processed through automated workflows, and deploy sandboxing techniques to isolate PDF processing activities. Network segmentation and access controls should be enforced to limit exposure of vulnerable systems, while regular security assessments should include vulnerability scanning for outdated Poppler installations. The fix typically involves implementing proper recursion depth limiting within the JBIG2 decoding process and adding robust bounds checking to prevent excessive memory consumption. Additionally, organizations should consider implementing automated monitoring and alerting for unusual processing patterns that might indicate exploitation attempts, and maintain updated threat intelligence feeds to stay informed about similar vulnerabilities in related software components.