CVE-2018-18498 in Firefox
Summary
by MITRE
A potential vulnerability leading to an integer overflow can occur during buffer size calculations for images when a raw value is used instead of the checked value. This leads to a possible out-of-bounds write. This vulnerability affects Thunderbird < 60.4, Firefox ESR < 60.4, and Firefox < 64.
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Analysis
by VulDB Data Team • 05/13/2020
The vulnerability identified as CVE-2018-18498 represents a critical integer overflow condition that manifests during image buffer size calculations within Mozilla's web browser and email client implementations. This flaw resides in the handling of raw numerical values during memory allocation processes, where unchecked integer values are used instead of properly validated and bounded calculations. The issue stems from inadequate input validation mechanisms that fail to properly constrain buffer size parameters, creating a scenario where maliciously crafted image data can trigger unexpected memory behavior.
The technical execution of this vulnerability occurs when the application processes image files and calculates buffer sizes for memory allocation. When raw values are directly used in these calculations without proper overflow checking, an attacker can manipulate image data to cause integer overflow conditions. This overflow results in incorrect buffer size calculations that can lead to out-of-bounds memory writes, potentially allowing arbitrary code execution or system instability. The vulnerability specifically affects the image processing libraries within Mozilla's rendering engines, where buffer allocation routines do not properly validate input parameters against maximum allowable values.
The operational impact of CVE-2018-18498 extends across multiple affected software versions including Thunderbird versions prior to 60.4, Firefox Extended Support Release versions prior to 60.4, and standard Firefox versions prior to 64. This widespread vulnerability affects users who process image content through these applications, making it particularly dangerous in environments where users may encounter maliciously crafted image files. The vulnerability can be exploited through various attack vectors including web browsing, email attachments, and image processing workflows, potentially enabling remote code execution or privilege escalation depending on the target system configuration.
Security implications of this vulnerability align with CWE-190, which specifically addresses integer overflow conditions that can lead to memory corruption, and maps to ATT&CK technique T1059 for remote code execution through application exploitation. The vulnerability demonstrates poor input validation practices and inadequate memory safety mechanisms that are commonly exploited in browser-based attacks. Mitigation strategies include immediate deployment of patched versions from Mozilla, implementation of strict input validation controls, and application of security hardening measures such as address space layout randomization and stack canaries to reduce exploitability. Organizations should prioritize patch management for affected versions and consider network segmentation to limit exposure while awaiting full deployment of security updates.