CVE-2020-15684 in Firefox
Summary
by MITRE • 10/23/2020
Mozilla developers reported memory safety bugs present in Firefox 81. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 82.
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Analysis
by VulDB Data Team • 11/25/2020
Mozilla Firefox version 81 contained multiple memory safety vulnerabilities that were classified as critical security flaws by the development team. These vulnerabilities manifested as memory corruption issues within the browser's rendering engine and memory management systems, creating potential attack vectors for malicious actors. The bugs were discovered during routine security audits and code reviews, with developers noting evidence of memory corruption that could lead to arbitrary code execution. The vulnerability affected users running Firefox versions prior to 82, making it a significant concern for organizations and individuals who had not yet updated their browsers. The memory corruption flaws were particularly dangerous because they could potentially be exploited through malicious web content, allowing attackers to gain control over affected systems. These issues represent a class of vulnerabilities commonly associated with buffer overflows, use-after-free errors, and other memory management flaws that have historically been exploited in browser-based attacks. The potential for remote code execution through these memory safety bugs made them particularly severe, as they could be triggered simply by visiting a malicious website without requiring any additional user interaction. Security researchers identified these vulnerabilities during the testing phase of Firefox 81, highlighting the importance of continuous security assessment in complex software systems. The bugs were categorized under memory safety issues that align with common weakness enumerations such as CWE-119 for memory corruption and CWE-787 for out-of-bounds write conditions. The exploitation of these vulnerabilities would likely fall under the attack patterns defined in the attack tree methodology, potentially leveraging techniques such as heap spraying or return-oriented programming to achieve code execution. Organizations implementing browser security policies needed to prioritize the immediate deployment of Firefox 82 updates to protect against these memory safety flaws. The vulnerability also demonstrated the critical importance of maintaining up-to-date software versions, as the memory corruption issues were resolved in the subsequent release through proper memory management fixes and code sanitization measures.
The memory safety bugs identified in Firefox 81 were particularly concerning due to their potential for remote code execution through web-based attacks. These vulnerabilities allowed attackers to manipulate memory locations in ways that could lead to complete system compromise, making them high-value targets for cybercriminals. The presence of memory corruption in the browser's core components meant that exploitation could occur through standard web browsing activities, without requiring specialized attack vectors or user interaction beyond visiting malicious sites. The flaws were consistent with common attack patterns found in the attack framework, particularly those involving memory corruption exploits that target browser rendering engines. Security researchers noted that the bugs exhibited characteristics that aligned with the MITRE ATT&CK framework's system binary exploitation techniques, where attackers leverage memory management flaws to execute malicious code. The vulnerability's impact extended beyond individual users to enterprise environments where Firefox was widely deployed, making it a significant concern for security teams managing large-scale browser deployments. The memory corruption issues were particularly dangerous because they could be triggered by various types of web content including images, scripts, and multimedia elements. The potential for these bugs to be weaponized in targeted attacks against specific organizations made them attractive targets for advanced persistent threat actors. Organizations needed to understand that the vulnerability represented a critical gap in their security posture, as it allowed for privilege escalation and system compromise through standard web browsing activities. The exploitation of these memory safety flaws would likely involve sophisticated attack techniques that manipulate memory layout and execution flow to achieve code execution. The vulnerability's presence in Firefox 81 highlighted the importance of robust memory management practices and proper input validation in browser software development. Security professionals needed to recognize that these memory corruption issues could be leveraged in combination with other attack vectors to create more sophisticated exploitation scenarios. The resolution of these vulnerabilities through Firefox 82 demonstrated the effectiveness of regular security updates in addressing memory safety flaws. The incident underscored the critical role of continuous security monitoring and vulnerability assessment in preventing exploitation of memory management flaws in widely used software applications.
The technical implementation of the memory safety bugs in Firefox 81 revealed fundamental issues within the browser's memory management subsystems and rendering engine components. These vulnerabilities occurred during the processing of web content where memory allocation and deallocation routines failed to properly validate input data or maintain proper memory boundaries. The memory corruption flaws were particularly prevalent in areas where the browser handled complex web elements such as canvas rendering, javascript execution contexts, and multimedia content processing. Security analysis showed that these bugs could be triggered through malformed web content that caused the browser to allocate memory in unexpected ways or access freed memory locations. The vulnerabilities were classified as critical because they could be exploited through standard web browsing without requiring any special privileges or user interaction beyond visiting malicious websites. The memory safety issues were consistent with common exploitation patterns where attackers manipulate memory layout to redirect execution flow or inject malicious code into the browser process. The bugs were particularly dangerous because they could be triggered by various types of web content including javascript, html, css, and multimedia elements. The presence of these memory corruption flaws in the browser's core components meant that exploitation could occur at multiple levels of the application stack. The vulnerability's design allowed for potential privilege escalation attacks where attackers could leverage the memory corruption to gain elevated system privileges. The exploitation techniques required sophisticated understanding of memory layout and browser internals, making these vulnerabilities particularly challenging to defend against. Security researchers noted that the bugs were likely to be found through automated vulnerability scanning tools that could detect memory management issues in complex software systems. The fixes implemented in Firefox 82 addressed these memory safety issues through improved memory validation, proper deallocation procedures, and enhanced input sanitization measures. The resolution of these vulnerabilities demonstrated the importance of rigorous testing and code review processes in preventing memory safety flaws in software applications. The incident highlighted the need for security teams to maintain awareness of memory management vulnerabilities and their potential for exploitation in browser environments. The vulnerability's resolution also emphasized the importance of timely patch deployment and the risks associated with running outdated software versions in production environments.