CVE-2015-7801 in OptiPNG
Summary
by MITRE
Use-after-free vulnerability in OptiPNG 0.6.4 allows remote attackers to execute arbitrary code via a crafted PNG file.
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Analysis
by VulDB Data Team • 07/26/2022
The CVE-2015-7801 vulnerability represents a critical use-after-free flaw in OptiPNG version 0.6.4 that exposes systems to remote code execution attacks through maliciously crafted png image files. This vulnerability falls under the broader category of memory safety issues and specifically aligns with CWE-416 which defines use-after-free conditions where program code attempts to access memory after it has been freed. The flaw occurs within the image processing pipeline of OptiPNG when handling malformed png files, creating a scenario where freed memory blocks are accessed during subsequent operations, potentially allowing attackers to manipulate program execution flow.
The technical exploitation of this vulnerability involves crafting a specially designed png file that triggers the use-after-free condition during OptiPNG's decompression and processing routines. When the vulnerable software attempts to free memory associated with certain png metadata structures and subsequently accesses this freed memory during image reconstruction, an attacker can manipulate the memory contents to redirect program execution. This type of vulnerability is particularly dangerous because it can be triggered remotely through web applications or file processing systems that utilize OptiPNG for image optimization, making it a prime target for automated exploitation campaigns.
The operational impact of CVE-2015-7801 extends beyond simple code execution as it can lead to complete system compromise when attackers leverage this vulnerability in conjunction with other attack vectors. Systems running vulnerable versions of OptiPNG, particularly web servers, content management systems, or automated image processing pipelines, become susceptible to remote code execution without requiring user interaction. The vulnerability demonstrates the importance of proper memory management practices and the need for comprehensive input validation in image processing libraries. Attackers can potentially use this flaw to install backdoors, escalate privileges, or perform data exfiltration from compromised systems.
Mitigation strategies for CVE-2015-7801 require immediate patching of OptiPNG to version 0.7.0 or later, which contains the necessary memory management fixes to prevent the use-after-free condition. Organizations should also implement defensive measures such as restricting file upload capabilities, employing sandboxed environments for image processing, and deploying intrusion detection systems that can identify malicious png file patterns. Network segmentation and access controls can help limit the potential impact of successful exploitation attempts, while regular security audits of image processing workflows can identify other vulnerable components. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date software libraries and implementing proper security controls in image processing environments. This flaw also aligns with ATT&CK technique T1059 which covers command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary commands on affected systems. Organizations should also consider implementing application whitelisting policies to prevent execution of vulnerable versions of OptiPNG and related image processing tools.