CVE-2021-38572 in Foxit
Summary
by MITRE • 08/12/2021
An issue was discovered in Foxit Reader and PhantomPDF before 10.1.4. It allows writing to arbitrary files because the extractPages pathname is not validated.
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Analysis
by VulDB Data Team • 08/16/2021
The vulnerability identified as CVE-2021-38572 represents a critical file system manipulation flaw affecting Foxit Reader and PhantomPDF software versions prior to 10.1.4. This security weakness stems from inadequate input validation within the extractPages functionality, creating a pathway for malicious actors to exploit the application's file handling mechanisms. The issue manifests when the software processes pathname inputs during page extraction operations, failing to properly validate or sanitize user-supplied file paths that could potentially be manipulated to write data to unintended locations on the target system. This vulnerability falls under the category of improper input validation as classified by CWE-20, which specifically addresses weaknesses in input validation that can lead to various security exploits including arbitrary file operations.
The technical exploitation of this vulnerability enables attackers to perform unauthorized file system operations by crafting malicious input that bypasses normal file path validation checks. When the extractPages function processes a pathname parameter without proper validation, it allows attackers to specify absolute or relative paths that may point to sensitive system locations, user directories, or critical application files. This flaw essentially grants remote attackers the ability to write arbitrary files to locations determined by the attacker, potentially leading to privilege escalation, data corruption, or system compromise. The vulnerability's impact is particularly severe because it operates at the file system level, allowing for direct manipulation of stored data without requiring elevated privileges beyond those normally associated with PDF processing operations.
From an operational perspective, this vulnerability creates significant risks for organizations relying on Foxit Reader or PhantomPDF for document management and processing. Attackers could leverage this flaw to overwrite critical system files, inject malicious code into PDF documents, or manipulate existing files to disrupt normal business operations. The attack surface extends beyond simple file writing to include potential privilege escalation scenarios where attackers might target configuration files, system executables, or user data repositories. The vulnerability's presence in widely-used PDF processing software means that any system running affected versions could be compromised, making it a prime target for automated exploitation campaigns targeting enterprise networks where these applications are commonly deployed.
Security mitigations for CVE-2021-38572 primarily focus on immediate software updates and patches provided by Foxit Corporation to address the specific input validation flaw in the extractPages functionality. Organizations should prioritize upgrading to Foxit Reader and PhantomPDF version 10.1.4 or later, which contains the necessary fixes to validate pathname inputs properly. Additional defensive measures include implementing strict file system access controls, monitoring for unusual file system operations, and deploying application whitelisting solutions to restrict execution of unauthorized file operations. Network segmentation and privilege separation can help limit the potential impact of exploitation, while regular security audits of document processing workflows should be conducted to identify any remaining vulnerabilities. The ATT&CK framework categorizes this type of vulnerability under T1059 Command and Scripting Interpreter and T1074 Data Staged, as it enables attackers to manipulate system resources through legitimate application interfaces while potentially staging malicious payloads for execution.