CVE-2018-9947 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.0.29935. 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 parsing of BMP images. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length, heap-based buffer. An attacker can leverage this vulnerability to execute code under the context of the current process. Was ZDI-CAN-5472.
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Analysis
by VulDB Data Team • 07/14/2024
CVE-2018-9947 represents a critical buffer overflow vulnerability affecting Foxit Reader version 9.0.0.29935 that enables remote code execution through malicious BMP image files. This vulnerability resides in the image parsing functionality where the software fails to properly validate the length of user-supplied data before copying it into a fixed-length heap-based buffer. The flaw operates under CWE-121, which classifies buffer overflow conditions where data is copied into a buffer without adequate bounds checking, leading to memory corruption that can be exploited by attackers.
The exploitation mechanism requires user interaction through either visiting a malicious webpage or opening a crafted BMP file, making this a typical client-side attack vector. When Foxit Reader processes a malformed BMP image, the insufficient input validation causes a buffer overflow condition that allows attackers to overwrite adjacent memory locations. This memory corruption can be manipulated to redirect program execution flow, enabling arbitrary code execution under the privileges of the currently running Foxit Reader process. The vulnerability demonstrates characteristics consistent with ATT&CK technique T1203, which involves the use of malicious files to gain code execution in legitimate software applications.
The operational impact of this vulnerability extends beyond simple code execution as it provides attackers with a persistent foothold within the victim's system. Since Foxit Reader is commonly used for document viewing and PDF processing, the attack surface is broad, particularly in enterprise environments where document handling is frequent. The heap-based buffer overflow creates opportunities for attackers to escalate privileges or inject malicious payloads that can persist across system sessions. The vulnerability's exploitation requires minimal user interaction beyond normal document opening behavior, making it particularly dangerous in targeted attack scenarios where social engineering can be employed to deliver malicious BMP files.
Mitigation strategies should focus on immediate software updates to patched versions of Foxit Reader, as well as network-level defenses such as content filtering and sandboxing of document attachments. Organizations should implement strict file type validation and restrict the execution of potentially malicious image files through security policies. The vulnerability highlights the importance of proper input validation and bounds checking in multimedia processing libraries, as demonstrated by the ZDI-CAN-5472 reference indicating this issue was recognized and tracked by the Zero Day Initiative. Security teams should also consider implementing monitoring for unusual document processing activities and network traffic patterns that might indicate exploitation attempts.