CVE-2017-7774 in Firefox
Summary
by MITRE
Out-of-bounds read in Graphite2 Library in Firefox before 54 in graphite2::Silf::readGraphite function.
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Analysis
by VulDB Data Team • 05/29/2020
The vulnerability CVE-2017-7774 represents a critical out-of-bounds read flaw within the graphite2 library that is integrated into Mozilla Firefox browsers. This issue specifically affects versions prior to Firefox 54 and occurs within the graphite2::Silf::readGraphite function, which handles font rendering operations for complex text layouts. The graphite2 library serves as a core component for processing advanced typography and international text rendering, making this vulnerability particularly dangerous as it can be triggered during normal browsing activities when encountering specially crafted text content.
The technical implementation of this vulnerability stems from improper bounds checking within the font processing pipeline. When Firefox processes text that utilizes the graphite2 library for rendering, the readGraphite function fails to validate input parameters adequately before accessing memory locations. This allows an attacker to craft malicious text content that, when rendered by the browser, causes the function to read memory beyond its allocated bounds. The flaw manifests as a classic buffer over-read condition that can potentially lead to information disclosure, application crashes, or in more severe scenarios, arbitrary code execution depending on memory layout and exploitation conditions.
The operational impact of this vulnerability extends beyond simple browser instability as it represents a significant security risk for end users. Attackers can exploit this weakness by delivering malicious web content that triggers the vulnerable code path when users browse to compromised websites. The vulnerability can be particularly insidious because it operates within the rendering engine where normal user interactions with text content can inadvertently trigger the exploit. This makes it difficult to defend against through traditional network-based security measures and requires immediate remediation through browser updates. The flaw affects the core rendering capabilities of Firefox, potentially compromising the entire browsing session and exposing user data to unauthorized access.
Mitigation strategies for CVE-2017-7774 primarily focus on immediate browser updates to versions 54 or later where the vulnerability has been patched. Organizations should implement comprehensive patch management procedures to ensure all Firefox installations are updated promptly. Additionally, security teams should monitor for exploitation attempts through web application firewalls and network intrusion detection systems that can identify suspicious text rendering patterns. The vulnerability aligns with CWE-129, which covers improper validation of array index, and can be mapped to ATT&CK technique T1059.007 for application layer attacks. Regular security assessments of browser configurations and user education about avoiding untrusted web content can further reduce the attack surface. System administrators should also consider implementing sandboxing measures and restricting browser capabilities in enterprise environments to limit potential exploitation impact.