CVE-2019-6765 in PhantomPDF
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit PhantomPDF 9.4.1.16828. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the conversion of HTML files to PDF. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated object. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-8170.
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Analysis
by VulDB Data Team • 09/26/2023
The vulnerability identified as CVE-2019-6765 represents a critical security flaw in Foxit PhantomPDF version 9.4.1.16828 that enables remote code execution through improper input validation during HTML to PDF conversion processes. This vulnerability operates under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions where an application accesses memory beyond the bounds of a allocated buffer. The flaw manifests when the software processes user-supplied HTML content that undergoes conversion to PDF format, creating a pathway for malicious actors to exploit the system through carefully crafted input data.
The technical implementation of this vulnerability stems from insufficient validation mechanisms within the PDF conversion engine that handles HTML file processing. When a user visits a malicious webpage or opens a specially crafted HTML file, the application's handling of the input data fails to properly bounds-check memory allocations, leading to a read past the end of an allocated object. This memory access violation occurs during the transformation process where HTML elements are converted into PDF structures, allowing an attacker to manipulate memory contents and potentially execute arbitrary code within the context of the current process. The vulnerability specifically aligns with ATT&CK technique T1203, which involves exploiting software vulnerabilities to gain code execution privileges.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the ability to operate within the privileges of the PhantomPDF application, potentially compromising the entire system if the application runs with elevated permissions. This flaw requires user interaction to be exploited, making it particularly dangerous in social engineering campaigns where victims might be诱导 to visit malicious websites or open infected files. The vulnerability's classification as a remote code execution flaw means that attackers can potentially compromise systems without requiring physical access or local network presence, making it particularly attractive for widespread exploitation campaigns. Organizations using this version of Foxit PhantomPDF face significant risk, as the vulnerability could be leveraged to establish persistent access, escalate privileges, or deploy additional malicious payloads.
Mitigation strategies for CVE-2019-6765 should prioritize immediate patching of affected systems with the vendor-provided security updates. Organizations should implement network segmentation and web filtering controls to prevent access to known malicious domains that might host exploit payloads. Additionally, user education programs should emphasize the importance of avoiding suspicious websites and untrusted file attachments, particularly when dealing with PDF documents. The vulnerability highlights the importance of proper input validation and bounds checking in software development practices, aligning with security standards such as those outlined in the OWASP Top Ten and NIST cybersecurity guidelines. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other software components, while implementing application whitelisting policies can provide additional defense-in-depth measures against exploitation attempts.