CVE-2011-1908 in Foxit
Summary
by MITRE
Integer overflow in the Type 1 font decoder in the FreeType engine in Foxit Reader before 4.0.0.0619 allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a crafted font in a PDF document.
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Analysis
by VulDB Data Team • 01/13/2025
The vulnerability identified as CVE-2011-1908 represents a critical integer overflow condition within the FreeType font engine implementation used by Foxit Reader version 4.0.0.0619 and earlier. This flaw exists specifically within the Type 1 font decoder component that processes PostScript-based font formats commonly embedded in PDF documents. The vulnerability arises from inadequate input validation and overflow handling when processing malformed font data structures that contain excessively large integer values. When the decoder attempts to allocate memory or perform arithmetic operations with these oversized integers, the result exceeds the maximum representable value for the data type, causing unpredictable behavior in the application's memory management systems.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a malicious PDF document containing a specially designed Type 1 font with integer values that trigger the overflow condition. The integer overflow manifests during font processing operations where the application calculates buffer sizes or memory allocation requirements based on malformed font parameters. This overflow can result in heap corruption, where adjacent memory locations become overwritten with unexpected values, potentially allowing attackers to manipulate program execution flow. The vulnerability maps to CWE-190, which specifically addresses integer overflow conditions, and aligns with ATT&CK technique T1059.007 for execution through remote code injection. The flaw demonstrates a classic buffer overflow pattern where insufficient bounds checking enables attackers to manipulate memory layout and potentially execute arbitrary code.
The operational impact of this vulnerability extends beyond simple application crashes to encompass full system compromise in certain scenarios. When successfully exploited, the integer overflow can cause Foxit Reader to crash or become unstable, resulting in denial of service for legitimate users. However, the more severe implications arise from potential code execution capabilities that could allow attackers to gain unauthorized access to systems where the vulnerable software is installed. The vulnerability affects users who open PDF documents from untrusted sources, making it particularly dangerous in enterprise environments where PDF documents are frequently shared. The exploitation requires minimal user interaction beyond opening the malicious document, making it a significant threat vector for social engineering campaigns.
Mitigation strategies for this vulnerability involve immediate software updates to Foxit Reader version 4.0.0.0619 or later, which contain patched implementations of the FreeType engine with proper integer overflow protections. Organizations should implement comprehensive patch management procedures to ensure all instances of the vulnerable software are updated promptly. Network-level defenses can include PDF content filtering and sandboxing mechanisms that isolate document processing from critical system resources. Additional protective measures involve restricting user permissions when opening PDF documents and implementing application whitelisting policies that limit execution of potentially malicious code. Security monitoring should focus on detecting unusual memory allocation patterns and process behavior that might indicate exploitation attempts. The vulnerability highlights the importance of robust input validation in font processing libraries and demonstrates how seemingly benign document elements can serve as attack vectors in modern software applications.