CVE-2017-9776 in Poppler
Summary
by MITRE
Integer overflow leading to Heap buffer overflow in JBIG2Stream.cc in pdftocairo in Poppler before 0.56 allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a crafted PDF document.
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Analysis
by VulDB Data Team • 12/08/2022
The vulnerability identified as CVE-2017-9776 represents a critical integer overflow condition that manifests as a heap buffer overflow within the JBIG2Stream.cc component of Poppler's pdftocairo utility. This flaw exists in Poppler versions prior to 0.56 and enables remote attackers to manipulate the application through carefully crafted PDF documents. The vulnerability stems from insufficient input validation and arithmetic overflow handling during the processing of JBIG2 compressed image data within PDF files.
The technical implementation of this vulnerability occurs when the Poppler library processes JBIG2 streams contained within PDF documents. During the decompression and rendering process, the application fails to properly validate integer values used for memory allocation calculations. When an attacker crafts a PDF document containing malicious JBIG2 data with oversized dimensions or malformed parameters, the integer overflow causes the system to allocate insufficient memory for buffer operations. This results in memory corruption that manifests as heap buffer overflow conditions, where adjacent memory regions become overwritten or accessed beyond their allocated boundaries.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable more sophisticated attacks. Remote attackers can exploit this vulnerability to cause application crashes and system instability, effectively creating a denial of service condition that disrupts legitimate PDF processing operations. In some cases, the heap corruption may allow for arbitrary code execution or privilege escalation depending on the execution environment and memory layout. The vulnerability affects any system that utilizes Poppler's pdftocairo utility for PDF to image conversion, including web applications, document processing servers, and desktop applications that rely on this library for PDF rendering capabilities.
The root cause of this vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions in software systems. The flaw demonstrates poor input validation practices and inadequate bounds checking during memory allocation operations. From an attack perspective, this vulnerability maps to multiple ATT&CK techniques including TA0005 (Defense Evasion) through application crash exploitation and potentially TA0004 (Privilege Escalation) if memory corruption leads to code execution. The vulnerability's remote exploitability means that attackers can leverage it through web browsers, email clients, or any PDF viewer that utilizes Poppler as a backend library, making it particularly dangerous in enterprise environments where PDF processing is common.
Mitigation strategies for CVE-2017-9776 primarily focus on immediate version updates to Poppler 0.56 or later, which contain the necessary patches to address the integer overflow conditions. Organizations should implement comprehensive patch management procedures to ensure all systems utilizing Poppler libraries receive the security updates promptly. Additionally, input validation measures should be enhanced at the application level, including implementing strict bounds checking for image dimensions and memory allocation calculations. Network segmentation and application whitelisting can provide additional defense-in-depth measures to limit potential exploitation paths. Regular security assessments and vulnerability scanning should be conducted to identify systems running vulnerable versions of Poppler and ensure proper remediation. System administrators should also consider implementing sandboxing techniques for PDF processing applications to contain potential exploitation attempts and limit the impact of successful attacks.