CVE-2020-28969 in PDF ShapingUp
Summary
by MITRE • 10/23/2021
Aplioxio PDF ShapingUp 5.0.0.139 contains a buffer overflow which allows attackers to cause a denial of service (DoS) via a crafted PDF file.
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Analysis
by VulDB Data Team • 10/29/2021
The vulnerability identified as CVE-2020-28969 affects Aplioxio PDF ShapingUp version 5.0.0.139 and represents a critical buffer overflow condition that can be exploited to trigger a denial of service scenario. This flaw resides within the PDF processing functionality of the software, specifically when handling malformed or crafted PDF files that contain oversized data structures or malformed memory allocations. The buffer overflow occurs during the parsing and rendering of PDF content where insufficient bounds checking is performed on user-supplied input data, allowing an attacker to manipulate memory layout and potentially disrupt normal application operation.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the PDF parser component of ShapingUp. When the application encounters a specially crafted PDF file containing oversized or malformed data elements, the memory allocation routines fail to properly validate the size of incoming buffers before copying data into them. This condition creates a scenario where attacker-controlled data can overwrite adjacent memory locations, leading to application instability and eventual crash. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which occurs when data is copied into a buffer without proper size validation, and under CWE-122 as heap-based buffer overflow when heap memory is improperly managed. The attack surface is particularly concerning as PDF files are commonly encountered in enterprise environments and can be delivered through various attack vectors including email attachments, web downloads, and document sharing platforms.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable more sophisticated attack scenarios. While the primary effect manifests as a denial of service condition that prevents legitimate users from accessing PDF processing functionality, the underlying memory corruption could theoretically be exploited to execute arbitrary code or escalate privileges depending on the execution environment. The vulnerability affects organizations that rely on Aplioxio PDF ShapingUp for document processing, particularly those in industries handling sensitive documents such as financial services, legal firms, healthcare organizations, and government agencies. The attack complexity is relatively low as it requires only the ability to deliver a malicious PDF file to the target system, making it an attractive vector for both automated attacks and targeted campaigns.
Mitigation strategies for CVE-2020-28969 should prioritize immediate software updates from Aplioxio to address the buffer overflow vulnerability through proper bounds checking and memory management practices. Organizations should implement defensive measures including PDF file validation at network perimeters, sandboxing of PDF processing operations, and network segmentation to limit potential attack impact. The implementation of web application firewalls and content inspection systems can help detect and block malicious PDF files before they reach vulnerable systems. Additionally, security teams should establish monitoring procedures to detect unusual application behavior that might indicate exploitation attempts. According to ATT&CK framework, this vulnerability maps to technique T1203 (Exploitation for Client Execution) and T1499 (Endpoint Denial of Service), with potential lateral movement implications if the attack successfully compromises system integrity. Regular vulnerability assessments and penetration testing should be conducted to identify similar memory corruption vulnerabilities in other PDF processing libraries and document management systems within the organization's infrastructure.