CVE-2017-13056 in PDF-XChange
Summary
by MITRE
The launchURL function in PDF-XChange Viewer 2.5 (Build 314.0) might allow remote attackers to execute arbitrary code via a crafted PDF file.
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Analysis
by VulDB Data Team • 01/19/2023
The vulnerability identified as CVE-2017-13056 represents a critical remote code execution flaw within PDF-XChange Viewer version 2.5 build 314.0. This security defect resides in the launchURL function which is designed to handle URL launching operations within the PDF viewer application. The vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly process maliciously crafted PDF files containing specially constructed URL parameters. Attackers can exploit this weakness by crafting malicious PDF documents that contain embedded URLs with malicious payloads, which when processed by the vulnerable viewer application can trigger arbitrary code execution on the target system.
The technical implementation of this vulnerability aligns with common software security flaws categorized under CWE-78 and CWE-79, which respectively address command injection and cross-site scripting vulnerabilities. The flaw manifests when the launchURL function processes user-supplied input without proper validation, allowing attackers to inject malicious commands that bypass normal execution boundaries. The PDF-XChange Viewer application fails to properly sanitize URL parameters extracted from PDF documents, creating an attack surface where malicious code can be executed with the privileges of the user running the viewer. This represents a classic buffer overflow or injection vulnerability that leverages the application's trust in user-provided data without sufficient verification mechanisms.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with a potential foothold for more sophisticated attacks within the target environment. An attacker who successfully exploits this vulnerability can execute arbitrary commands on the victim's system, potentially leading to complete system compromise, data exfiltration, or lateral movement within a network. The attack vector requires only that a user opens a maliciously crafted PDF file with the vulnerable PDF-XChange Viewer application, making this vulnerability particularly dangerous in phishing campaigns or targeted attacks. The vulnerability affects any system running the specific version of PDF-XChange Viewer mentioned in the CVE, with no additional privileges required for exploitation beyond the ability to present a malicious PDF file to an unsuspecting user.
Mitigation strategies for this vulnerability should focus on immediate remediation through software updates and patches provided by the vendor. Organizations should prioritize updating to the latest version of PDF-XChange Viewer that addresses this specific flaw, as the vendor has likely released a patched version that properly validates and sanitizes URL parameters. Network-based mitigations include implementing strict PDF file validation policies and blocking suspicious PDF content at network boundaries, though these approaches provide only partial protection since the vulnerability exists within the application itself. Additional protective measures include user education to avoid opening untrusted PDF files, implementing application whitelisting policies, and ensuring that the vulnerable application is not automatically executed when PDF files are opened. Security professionals should also consider monitoring for suspicious URL patterns and command execution activities that might indicate exploitation attempts, as this vulnerability can be leveraged for persistent access and data theft operations. The ATT&CK framework categorizes this vulnerability under T1203 - Exploitation for Client Execution, highlighting the importance of protecting endpoint applications from malicious file execution and ensuring proper input validation mechanisms are in place to prevent such exploitation scenarios.