CVE-2017-5467 in Firefox
Summary
by MITRE
A potential memory corruption and crash when using Skia content when drawing content outside of the bounds of a clipping region. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.
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Analysis
by VulDB Data Team • 09/18/2020
The vulnerability identified as CVE-2017-5467 represents a critical memory corruption issue within the Skia graphics library that underpins web rendering in Mozilla Firefox and Thunderbird applications. This flaw manifests when the graphics rendering engine processes content that extends beyond the boundaries of a defined clipping region, creating a scenario where memory corruption can occur during the drawing operations. The vulnerability specifically impacts versions of Firefox ESR prior to 52.1, Firefox versions prior to 53, and Thunderbird versions prior to 52.1, making it a widespread concern across multiple Mozilla products. The underlying technical mechanism involves the improper handling of memory allocation and boundary checking when Skia attempts to render graphical elements that fall outside the designated clipping area, potentially leading to arbitrary code execution or application crashes.
The operational impact of this vulnerability extends beyond simple application instability, as it creates potential attack vectors for remote code execution. When an attacker can manipulate the rendering of content outside clipping bounds, they may be able to trigger memory corruption that could allow for privilege escalation or system compromise. This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of improper boundary checking in memory management. The flaw particularly affects web content rendering where malicious actors could craft specially designed web pages that exploit this condition during normal browsing operations. The attack surface is significant given that Skia is extensively used throughout the Mozilla ecosystem for rendering various types of graphical content including images, text, and complex visual elements.
Security researchers have classified this vulnerability as particularly dangerous due to its potential for remote code execution when combined with other exploitation techniques. The flaw operates at the graphics rendering layer, meaning that even seemingly benign web content could be leveraged to trigger the memory corruption. This vulnerability demonstrates the complexity of modern browser security where issues in graphics libraries can have cascading effects throughout the entire application stack. Mitigation strategies include immediate patching of affected versions, enabling sandboxing features, and implementing additional content filtering mechanisms. Organizations should also consider deploying network-level protections and monitoring for suspicious rendering behavior. The vulnerability highlights the importance of comprehensive memory safety testing and the need for robust input validation in graphics rendering systems. According to ATT&CK framework, this vulnerability could be categorized under privilege escalation and execution techniques, as it potentially allows attackers to execute arbitrary code with the privileges of the affected application. The remediation process requires careful attention to ensure that updates don't introduce compatibility issues while maintaining the security posture of the affected systems.