CVE-2019-12360 in Xpdf
Summary
by MITRE
A stack-based buffer over-read exists in FoFiTrueType::dumpString in fofi/FoFiTrueType.cc in Xpdf 4.01.01. It can, for example, be triggered by sending crafted TrueType data in a PDF document to the pdftops tool. It might allow an attacker to cause Denial of Service or leak memory data into dump content.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 09/24/2023
The vulnerability CVE-2019-12360 represents a stack-based buffer over-read in the Xpdf library's TrueType font handling component, specifically within the FoFiTrueType::dumpString function located in fofi/FoFiTrueType.cc. This flaw exists in Xpdf version 4.01.01 and demonstrates a classic memory safety issue that can be exploited through crafted input data. The vulnerability occurs when the pdftops tool processes PDF documents containing maliciously constructed TrueType font data, creating a scenario where the application attempts to read beyond the bounds of allocated memory buffers.
The technical implementation of this vulnerability stems from inadequate input validation and boundary checking within the font parsing routine. When Xpdf encounters a TrueType font structure within a PDF document, the FoFiTrueType::dumpString function processes font data without sufficient verification of array bounds or data length parameters. This allows an attacker to construct a malicious PDF document with specially crafted TrueType font data that causes the application to access memory locations beyond the intended buffer boundaries. The over-read condition can manifest as either a denial of service attack that crashes the application or as a memory disclosure vulnerability that leaks sensitive information from adjacent memory regions.
From an operational perspective, this vulnerability presents significant risks to systems that process untrusted PDF documents, particularly in environments where automated PDF conversion tools are deployed. The attack vector is relatively straightforward since it only requires the delivery of a malicious PDF document to trigger the vulnerability, making it accessible to attackers with minimal technical expertise. The potential impact includes service disruption through application crashes, which can be exploited in denial of service scenarios, or information disclosure that could reveal sensitive data from memory, potentially including cryptographic keys, user credentials, or other confidential information. The vulnerability affects the pdftops tool specifically, which is commonly used in server environments for PDF to PostScript conversion, making it a critical concern for enterprise security.
Mitigation strategies for CVE-2019-12360 should focus on immediate patching of the Xpdf library to version 4.01.02 or later, which contains the necessary fixes for the buffer over-read condition. Organizations should also implement input validation controls at the network level, particularly for PDF processing systems, by employing sandboxing techniques and strict file format validation. Security monitoring should be enhanced to detect unusual patterns in PDF processing activities that might indicate exploitation attempts. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and can be categorized under ATT&CK technique T1203, which covers exploitation of vulnerabilities in document processing software. Additionally, implementing network segmentation and access controls for PDF processing systems can limit the potential impact of successful exploitation attempts. Organizations should also consider deploying intrusion detection systems capable of identifying malicious PDF content patterns that could trigger this specific vulnerability.