CVE-2018-12366 in Firefox
Summary
by MITRE
An invalid grid size during QCMS (color profile) transformations can result in the out-of-bounds read interpreted as a float value. This could leak private data into the output. This vulnerability affects Thunderbird < 60, Thunderbird < 52.9, Firefox ESR < 60.1, Firefox ESR < 52.9, and Firefox < 61.
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Analysis
by VulDB Data Team • 03/29/2023
The vulnerability identified as CVE-2018-12366 represents a critical memory safety issue within the color management system of Mozilla applications including Firefox and Thunderbird. This flaw exists in the Quality Color Management System (QCMS) component responsible for handling color profile transformations. The vulnerability manifests when processing malformed color profiles that contain invalid grid sizes during the transformation process. The technical implementation fails to properly validate input parameters before performing mathematical operations on color data, creating a condition where memory access occurs beyond the bounds of allocated buffers.
The core technical flaw stems from inadequate bounds checking within the QCMS color transformation algorithms. When the system encounters a color profile with an invalid grid size parameter, it proceeds to interpret this malformed data as a valid floating-point value for memory calculations. This improper handling creates an out-of-bounds read condition that can access adjacent memory locations containing sensitive information such as stack contents, heap data, or other application memory segments. The vulnerability is classified under CWE-129 as an insufficient input validation, specifically manifesting as an improper input validation issue that allows for memory access violations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially expose sensitive data from the application's memory space. Attackers could craft malicious color profiles designed to trigger this condition and extract private data including cryptographic keys, session tokens, or other confidential information stored in memory. The vulnerability affects multiple versions of Mozilla's browser and email client applications, making it particularly dangerous in environments where users might encounter untrusted color profiles through web content or email attachments. The issue impacts both regular Firefox releases and the Extended Support Release (ESR) versions, indicating a widespread exposure across different deployment scenarios.
Security researchers have mapped this vulnerability to ATT&CK technique T1059.007 which involves the use of scripting languages for exploitation, as the malicious color profiles could be delivered through web pages or email attachments containing embedded scripting elements. The vulnerability's exploitation requires minimal user interaction beyond viewing or processing the malicious content, making it particularly dangerous in phishing campaigns or web-based attacks. Mitigation strategies include updating to patched versions of Firefox and Thunderbird, implementing strict content filtering for color profile processing, and deploying network-based intrusion detection systems that can identify and block malicious color profile content. Organizations should prioritize patch management for affected versions and consider implementing additional security controls such as sandboxing mechanisms to limit the potential impact of exploitation attempts. The vulnerability highlights the importance of robust input validation in multimedia processing components and serves as a reminder of the security risks associated with complex color management systems in modern web browsers and email clients.