CVE-2017-9924 in SWFTools
Summary
by MITRE
In SWFTools 2013-04-09-1007 on Windows, png2swf allows remote attackers to execute arbitrary code or cause a denial of service via a crafted file, related to a "User Mode Write AV starting at image00000000_00400000+0x000000000001b72a."
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Analysis
by VulDB Data Team • 10/23/2019
The vulnerability identified as CVE-2017-9924 affects SWFTools version 2013-04-09-1007 on Windows systems, specifically targeting the png2swf utility within this software suite. This represents a critical security flaw that could enable remote attackers to gain unauthorized execution capabilities or disrupt system availability. The vulnerability manifests through a specially crafted png file that, when processed by the png2swf tool, triggers unexpected behavior in the underlying memory management system. The technical details indicate that the flaw occurs during the handling of image data where a user mode write access violation takes place, suggesting a memory corruption issue that can be exploited to execute malicious code or cause system instability.
The core technical flaw involves a heap-based buffer overflow or memory corruption vulnerability that occurs during the conversion process from png to swf format. When the png2swf utility processes a maliciously crafted png file, it fails to properly validate or sanitize the input data, leading to memory access violations at a specific memory address pattern. The memory access violation occurs at image00000000_00400000+0x000000000001b72a, indicating that the attack exploits a predictable memory layout that allows for code execution in the user mode context. This type of vulnerability falls under the CWE-121 heap-based buffer overflow category, which is a common vector for remote code execution attacks in multimedia processing applications. The vulnerability's classification aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary commands on the affected system.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides attackers with potential remote code execution capabilities that could lead to complete system compromise. An attacker could craft a malicious png file that, when opened or processed by a vulnerable system, would trigger the memory corruption and potentially allow for arbitrary code execution with the privileges of the user running the png2swf utility. This vulnerability affects organizations that rely on SWFTools for multimedia processing, particularly those that process untrusted png files from external sources or web applications. The exploitability of this vulnerability is heightened in environments where users might unknowingly process malicious files, making it particularly dangerous in enterprise settings where users may encounter such files through email attachments, web browsing, or file sharing platforms. The vulnerability also represents a significant concern for web applications that utilize SWFTools for image conversion services, as these systems could become attack vectors for broader network compromise.
Organizations should implement immediate mitigations including updating to the latest version of SWFTools where this vulnerability has been addressed, or applying patches specifically designed to fix the memory handling issues in the png2swf utility. System administrators should consider implementing strict input validation and sanitization for all image processing workflows, particularly when handling files from untrusted sources. Network-level protections such as web application firewalls and content filtering solutions can help prevent the delivery of malicious png files to vulnerable systems. Additionally, users should be educated about the risks of processing untrusted image files and organizations should implement principle of least privilege access controls for systems running SWFTools. The vulnerability also highlights the importance of regular security assessments and vulnerability scanning to identify similar issues in legacy software systems that may not receive ongoing security updates. Organizations should also consider implementing application whitelisting policies to restrict execution of potentially vulnerable utilities and ensure that only trusted software can run on critical systems.