CVE-2017-12955 in Exiv2
Summary
by MITRE
There is a heap-based buffer overflow in basicio.cpp of Exiv2 0.26. The vulnerability causes an out-of-bounds write in Exiv2::Image::printIFDStructure(), which may lead to remote denial of service or possibly unspecified other impact.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 11/08/2019
The heap-based buffer overflow vulnerability identified as CVE-2017-12955 resides within the Exiv2 library version 0.26, specifically in the basicio.cpp file. This flaw manifests during the execution of the Exiv2::Image::printIFDStructure() function, where improper input validation allows maliciously crafted data to trigger an out-of-bounds write operation. The vulnerability represents a critical security weakness that can be exploited through improper handling of image metadata structures, particularly when processing image files that contain malformed or crafted IFD (Image File Directory) data. The flaw stems from insufficient bounds checking mechanisms that fail to validate the size and structure of data being written to heap memory locations, creating opportunities for arbitrary code execution or system instability.
The technical implementation of this vulnerability involves the manipulation of image file structures that Exiv2 processes to extract and display metadata information. When the library encounters malformed IFD entries within image files, the printIFDStructure() function attempts to write data beyond the allocated heap buffer boundaries. This occurs because the code does not properly validate the length of IFD entries or the number of directory entries before attempting to process them, resulting in memory corruption that can be exploited by attackers. The heap-based nature of the vulnerability means that the overflow affects dynamically allocated memory segments, potentially allowing attackers to overwrite adjacent memory regions and corrupt program execution flow. This type of vulnerability is classified under CWE-121 as heap-based buffer overflow, which is a well-documented weakness in memory management practices that has been consistently identified in image processing libraries and multimedia applications.
The operational impact of CVE-2017-12955 extends beyond simple denial of service scenarios to encompass potential remote code execution and system compromise. Attackers can leverage this vulnerability by crafting malicious image files that contain specially constructed IFD structures designed to trigger the buffer overflow during normal library operations. When an application using Exiv2 processes such malicious files, the out-of-bounds write can result in arbitrary code execution, allowing remote attackers to gain control over the affected system. The vulnerability is particularly concerning because Exiv2 is widely used across numerous applications including photo viewers, content management systems, and digital asset management platforms, making the potential attack surface extensive. Additionally, the vulnerability can be exploited in web applications that process user-uploaded images, creating a significant risk for online services that rely on Exiv2 for metadata extraction and processing.
Mitigation strategies for CVE-2017-12955 should prioritize immediate patching of Exiv2 library versions prior to 0.27, as the vulnerability was addressed in subsequent releases through enhanced bounds checking and input validation mechanisms. Organizations should implement comprehensive application security measures including input sanitization, memory protection features, and regular security updates to prevent exploitation attempts. The vulnerability demonstrates the importance of proper memory management practices and input validation in multimedia processing libraries, aligning with ATT&CK technique T1068 which covers the exploitation of system privileges and memory corruption vulnerabilities. Security teams should also consider implementing network segmentation and application whitelisting to limit the potential impact of successful exploitation attempts, while monitoring for suspicious file processing activities that may indicate attempted exploitation of this vulnerability. The remediation process must include thorough testing of patched applications to ensure that the vulnerability has been effectively addressed without introducing regressions in functionality.