CVE-2018-5308 in PoDoFo
Summary
by MITRE
PoDoFo 0.9.5 does not properly validate memcpy arguments in the PdfMemoryOutputStream::Write function (base/PdfOutputStream.cpp). Remote attackers could leverage this vulnerability to cause a denial-of-service or possibly unspecified other impact via a crafted pdf file.
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Analysis
by VulDB Data Team • 05/26/2020
The vulnerability identified as CVE-2018-5308 resides within the PoDoFo library version 0.9.5, specifically within the PdfMemoryOutputStream::Write function located in base/PdfOutputStream.cpp. This flaw represents a classic buffer over-read condition that occurs when the library fails to properly validate the arguments passed to the memcpy function during memory operations. The issue manifests when processing maliciously crafted pdf files that contain malformed data structures designed to exploit the insufficient input validation mechanisms.
The technical implementation of this vulnerability stems from improper bounds checking within the memory copy operation where the PdfMemoryOutputStream::Write function does not adequately verify the size parameters before executing memcpy calls. When a remote attacker submits a specially crafted pdf file, the library processes the input data without sufficient validation, leading to a situation where memcpy attempts to copy more data than allocated buffer space allows. This condition creates a potential for memory corruption that can be exploited to trigger system instability or potentially enable more severe attack vectors.
From an operational perspective, this vulnerability presents significant risks to systems that rely on PoDoFo for pdf processing and manipulation. The denial-of-service impact means that legitimate pdf processing workflows can be disrupted by malicious files, potentially affecting business operations and user productivity. The unspecified other impacts suggest that beyond simple service disruption, attackers might be able to leverage this vulnerability for more sophisticated attacks including arbitrary code execution or information disclosure, depending on the specific memory layout and system configuration. The remote attack vector amplifies the threat surface since attackers can exploit this vulnerability without requiring local access to the target system.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a variant of memory safety issues that have been extensively documented in the cybersecurity community. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for command and scripting interpreter, as attackers might use this flaw to execute malicious code within the context of pdf processing applications. The impact is particularly concerning for organizations that process untrusted pdf documents, such as email servers, document management systems, or web applications that handle pdf uploads from external users.
Mitigation strategies should focus on immediate patching of the PoDoFo library to version 0.9.6 or later, which contains the necessary fixes for the memory validation issues. Organizations should also implement defensive measures such as input sanitization, pdf file validation, and sandboxing techniques to limit the potential impact of exploitation attempts. Network-based security controls including intrusion detection systems and web application firewalls should be configured to monitor for suspicious pdf file patterns that might indicate exploitation attempts. Additionally, regular security assessments and vulnerability scanning should be conducted to identify any other potential memory safety issues within the pdf processing pipeline and ensure that all dependencies are kept up to date with security patches.