CVE-2017-7544 in libexif
Summary
by MITRE
libexif through 0.6.21 is vulnerable to out-of-bounds heap read vulnerability in exif_data_save_data_entry function in libexif/exif-data.c caused by improper length computation of the allocated data of an ExifMnote entry which can cause denial-of-service or possibly information disclosure.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 12/30/2022
The vulnerability identified as CVE-2017-7544 represents a critical out-of-bounds heap read flaw within the libexif library version 0.6.21 and earlier. This issue resides in the exif_data_save_data_entry function located in the libexif/exif-data.c source file, making it a fundamental component of the digital image metadata processing pipeline. The flaw stems from improper length computation when allocating memory for ExifMnote entries, creating a scenario where the application processes memory regions beyond their intended boundaries.
The technical execution of this vulnerability occurs when libexif attempts to process Exif metadata within image files, particularly those containing malformed or crafted ExifMnote data structures. When the library calculates the memory allocation size for these entries, it fails to properly validate the input data length, leading to a situation where heap memory reads extend beyond allocated boundaries. This improper memory handling creates a condition where the application may access uninitialized memory regions or memory belonging to other data structures within the process heap.
The operational impact of CVE-2017-7544 manifests primarily as denial-of-service conditions, where applications relying on libexif for image metadata processing may crash or become unresponsive when encountering specially crafted Exif data. However, the vulnerability presents additional security implications beyond simple service disruption, as the out-of-bounds heap read may expose sensitive information from adjacent memory locations, potentially leading to information disclosure attacks. This characteristic places the vulnerability in the category of information exposure risks that can compromise system security and data confidentiality.
From a cybersecurity perspective, this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions in software systems, and demonstrates how improper memory management can create exploitable conditions. The flaw operates within the ATT&CK framework under the technique T1059.007 for command and scripting interpreter, as it affects applications that process image metadata, and potentially under T1557 for dynamic resolution, as it can be leveraged to extract memory contents. The vulnerability affects numerous applications that depend on libexif for image processing, including web servers, image viewers, and content management systems.
Mitigation strategies for CVE-2017-7544 require immediate patching of libexif to version 0.6.22 or later, which contains the necessary memory allocation corrections. System administrators should prioritize updating all applications that utilize libexif, particularly those handling untrusted image files from user uploads or external sources. Additionally, implementing input validation controls and sandboxing mechanisms around image processing functions can provide defense-in-depth measures. Organizations should also consider deploying intrusion detection systems that monitor for abnormal memory access patterns and implement proper memory safety controls such as address space layout randomization and stack canaries to reduce the exploitability of similar vulnerabilities.