CVE-2020-19499 in libheif
Summary
by MITRE • 07/22/2021
An issue was discovered in heif::Box_iref::get_references in libheif 1.4.0, allows attackers to cause a Denial of Service or possibly other unspecified impact due to an invalid memory read.
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Analysis
by VulDB Data Team • 07/26/2021
The vulnerability identified as CVE-2020-19499 represents a critical memory safety issue within the libheif library version 1.4.0, specifically affecting the heif::Box_iref::get_references function. This flaw manifests as an invalid memory read condition that can be exploited by malicious actors to disrupt system operations or potentially execute arbitrary code. The issue stems from inadequate input validation within the reference handling mechanism of the HEIF (High Efficiency Image Format) container specification implementation, where the library fails to properly sanitize or verify the structure of reference data before attempting to access memory locations.
The technical exploitation of this vulnerability occurs when an attacker crafts a malformed HEIF file containing crafted reference data within the iref (item reference) box structure. The heif::Box_iref::get_references function processes these references without sufficient bounds checking or memory validation, leading to an invalid memory read operation. This type of flaw falls under the CWE-125 vulnerability category, which specifically addresses out-of-bounds read conditions in software implementations. The vulnerability is particularly concerning because it can be triggered through normal file processing operations, making it accessible to attackers who simply need to present a specially crafted HEIF file to an application utilizing the vulnerable libheif library.
From an operational perspective, this vulnerability presents significant risk to systems that process HEIF image files, including web applications, mobile devices, and image processing software. The potential impact extends beyond simple denial of service to include information disclosure or privilege escalation depending on the execution environment. Attackers could leverage this weakness to cause applications to crash repeatedly, consume excessive system resources, or potentially extract sensitive memory contents through the invalid read operation. The vulnerability's exploitation aligns with ATT&CK technique T1203, which describes the use of execution through system binaries, and T1059, covering command and scripting interpreter usage, as attackers might attempt to trigger the vulnerability in various system contexts.
The mitigation strategy for CVE-2020-19499 requires immediate action to update the libheif library to version 1.4.1 or later, where the invalid memory read issue has been addressed through proper input validation and bounds checking mechanisms. System administrators should prioritize patching affected applications and services that utilize the vulnerable library, particularly those handling user-uploaded image content or processing external HEIF files. Additionally, implementing proper input sanitization at application level and deploying robust file validation routines can provide defense-in-depth measures against similar vulnerabilities. Organizations should also consider implementing network segmentation and access controls to limit exposure of systems that process HEIF files, while monitoring for unusual resource consumption patterns that might indicate exploitation attempts. The fix implemented in the patched version demonstrates proper memory management practices and adheres to secure coding guidelines that prevent unauthorized memory access patterns.